ORCID Profile
0000-0002-2576-7457
Current Organisations
Griffith University
,
University of Queensland
,
University of Sydney
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Medical Biochemistry: Proteins And Peptides | Medicinal and Biomolecular Chemistry | Biomolecular Modelling and Design | Biochemistry and Cell Biology | Biological And Medical Chemistry | Biologically Active Molecules | Enzymes | Biochemistry and Cell Biology not elsewhere classified |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Diagnostics | Treatments (e.g. chemicals, antibiotics) | Biological sciences
Related Links
Publications
Retinoic acid-dependent upregulation of mouse folate receptor-alpha expression in embryonic stem cells, and conservation of alternative splicing patterns.
Publisher: Elsevier BV
Date: 04-1999
Variability in the Generation of Induced Pluripotent Stem Cells: Importance for Disease Modeling
Publisher: Oxford University Press (OUP)
Date: 09-2012
Abstract: In the field of disease modeling, induced pluripotent stem cells (iPSCs) have become an appealing choice, especially for diseases that do not have an animal model. They can be generated from patients with known clinical features and compared with cells from healthy controls to identify the biological bases of disease. This study was undertaken to determine the variability in iPSC lines derived from different in iduals, with the aim of determining criteria for selecting iPSC lines for disease models. We generated and characterized 18 iPSC lines from eight donors and considered variability at three levels: (a) variability in the criteria that define iPSC lines as pluripotent cells, (b) variability in cell lines from different donors, and (c) variability in cell lines from the same donor. We found that variability in transgene expression and pluripotency marker levels did not prevent iPSCs from fulfilling all other criteria for pluripotency, including teratoma formation. We found low interin idual and interclonal variability in iPSCs that fulfilled the most stringent criteria for pluripotency, with very high correlation in their gene expression profiles. Interestingly, some cell lines exhibited reprogramming instability, spontaneously regressing from a fully to a partially reprogrammed state. This was associated with a low percentage of cells expressing the pluripotency marker stage-specific embryonic antigen-4. Our study shows that it is possible to define a similar “ground state” for each cell line as the basis for making patient versus control comparisons, an essential step in order to identify disease-associated variability above in idual and cell line variability.
A Grand Challenge. 3. Unbiased Phenotypic Function of Metabolites from Australia Plants Gloriosa superba and Alangium villosum against Parkinson's Disease
Publisher: American Chemical Society (ACS)
Date: 06-05-2020
The Ras target AF-6 is a substrate of the fam deubiquitinating enzyme.
Publisher: Rockefeller University Press
Date: 24-08-1998
Abstract: The Ras target AF-6 has been shown to serve as one of the peripheral components of cell–cell adhesions, and is thought to participate in cell–cell adhesion regulation downstream of Ras. We here purified an AF-6-interacting protein with a molecular mass of ∼220 kD (p220) to investigate the function of AF-6 at cell–cell adhesions. The peptide sequences of p220 were identical to the amino acid sequences of mouse Fam. Fam is homologous to a deubiquitinating enzyme in Drosophila, the product of the fat facets gene. Recent genetic analyses indicate that the deubiquitinating activity of the fat facets product plays a critical role in controlling the cell fate. We found that Fam accumulated at the cell–cell contact sites of MDCKII cells, but not at free ends of plasma membranes. Fam was partially colocalized with AF-6 and interacted with AF-6 in vivo and in vitro. We also showed that AF-6 was ubiquitinated in intact cells, and that Fam prevented the ubiquitination of AF-6.
STEM CELL MODELS FOR BIOMARKER DISCOVERY IN BRAIN DISEASE
Publisher: Elsevier
Date: 2011
Nitric oxide prevents aortic valve calcification by S-nitrosylation of USP9X to activate NOTCH signaling
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-02-2021
Abstract: The protective role of nitric oxide in calcific aortic valve disease is mediated by S-nitrosylation of proteins.
The Ubiquitin Ligase Itch Is Auto-ubiquitylated in Vivo and in Vitro but Is Protected from Degradation by Interacting with the Deubiquitylating Enzyme FAM/USP9X
Publisher: Elsevier BV
Date: 12-2006
Missense variant contribution to USP9X-female syndrome
Publisher: Springer Science and Business Media LLC
Date: 09-12-2020
DOI: 10.1038/S41525-020-00162-9
Abstract: USP9X is an X-chromosome gene that escapes X-inactivation. Loss or compromised function of USP9X leads to neurodevelopmental disorders in males and females. While males are impacted primarily by hemizygous partial loss-of-function missense variants, in females de novo heterozygous complete loss-of-function mutations predominate, and give rise to the clinically recognisable USP9X -female syndrome. Here we provide evidence of the contribution of USP9X missense and small in-frame deletion variants in USP9X -female syndrome also. We scrutinise the pathogenicity of eleven such variants, ten of which were novel. Combined application of variant prediction algorithms, protein structure modelling, and assessment under clinically relevant guidelines universally support their pathogenicity. The core phenotype of this cohort overlapped with previous descriptions of USP9X -female syndrome, but exposed heightened variability. Aggregate phenotypic information of 35 currently known females with predicted pathogenic variation in USP9X reaffirms the clinically recognisable USP9X -female syndrome, and highlights major differences when compared to USP9X -male associated neurodevelopmental disorders.
Grb2-Mediated Recruitment of USP9X to LAT Enhances Themis Stability following Thymic Selection
Publisher: The American Association of Immunologists
Date: 15-10-2017
Abstract: Themis is a new component of the TCR signaling machinery that plays a critical role during T cell development. The positive selection of immature CD4+CD8+ double-positive thymocytes and their commitment to the CD4+CD8− single-positive stage are impaired in Themis−/− mice, suggesting that Themis might be important to sustain TCR signals during these key developmental processes. However, the analysis of Themis mRNA levels revealed that Themis gene expression is rapidly extinguished during positive selection. We show in this article that Themis protein expression is increased in double-positive thymocytes undergoing positive selection and is sustained in immature single-positive thymocytes, despite the strong decrease in Themis mRNA levels in these subsets. We found that Themis stability is controlled by the ubiquitin-specific protease USP9X, which removes ubiquitin K48-linked chains on Themis following TCR engagement. Biochemical analyses indicate that USP9X binds directly to the N-terminal CABIT domain of Themis and indirectly to the adaptor protein Grb2, with the latter interaction enabling recruitment of Themis/USP9X complexes to LAT, thereby sustaining Themis expression following positive selection. Together, these data suggest that TCR-mediated signals enhance Themis stability upon T cell development and identify USP9X as a key regulator of Themis protein turnover.
Cloning and expression analysis of a novel mouse gene with sequence similarity to the Drosophila fat facets gene.
Publisher: Elsevier BV
Date: 04-1997
USP9X deubiquitylating enzyme maintains RAPTOR protein levels, mTORC1 signalling and proliferation in neural progenitors
Publisher: Springer Science and Business Media LLC
Date: 24-03-2017
DOI: 10.1038/S41598-017-00149-0
Abstract: USP9X, is highly expressed in neural progenitors and, essential for neural development in mice. In humans, mutations in USP9X are associated with neurodevelopmental disorders. To understand USP9X ’ s role in neural progenitors, we studied the effects of altering its expression in both the human neural progenitor cell line, ReNcell VM, as well as neural stem and progenitor cells derived from Nestin- cre conditionally deleted Usp9x mice. Decreasing USP9X resulted in ReNcell VM cells arresting in G0 cell cycle phase, with a concomitant decrease in mTORC1 signalling, a major regulator of G0/G1 cell cycle progression. Decreased mTORC1 signalling was also observed in Usp9x -null neurospheres and embryonic mouse brains. Further analyses revealed, (i) the canonical mTORC1 protein, RAPTOR, physically associates with Usp9x in embryonic brains, (ii) RAPTOR protein level is directly proportional to USP9X, in both loss- and gain-of-function experiments in cultured cells and, (iii) USP9X deubiquitlyating activity opposes the proteasomal degradation of RAPTOR. EdU incorporation assays confirmed Usp9x maintains the proliferation of neural progenitors similar to Raptor-null and rapamycin-treated neurospheres. Interestingly, loss of Usp9x increased the number of sphere-forming cells consistent with enhanced neural stem cell self-renewal. To our knowledge, USP9X is the first deubiquitylating enzyme shown to stabilize RAPTOR.
Deubiquitinating Enzyme USP9X Suppresses Tumor Growth via LATS Kinase and Core Components of the Hippo Pathway
Publisher: American Association for Cancer Research (AACR)
Date: 14-09-2017
DOI: 10.1158/0008-5472.CAN-16-3413
Abstract: The core LATS kinases of the Hippo tumor suppressor pathway phosphorylate and inhibit the downstream transcriptional co-activators YAP and TAZ, which are implicated in various cancers. Recent studies have identified various E3 ubiquitin ligases that negatively regulate the Hippo pathway via ubiquitination, yet few deubiquitinating enzymes (DUB) have been implicated. In this study, we report the DUB USP9X is an important regulator of the core kinases of this pathway. USP9X interacted strongly with LATS kinase and to a lesser extent with WW45, KIBRA, and Angiomotin, and LATS co-migrated exclusively with USP9X during gel filtration chromatography analysis. Knockdown of USP9X significantly downregulated and destabilized LATS and resulted in enhanced nuclear translocation of YAP and TAZ, accompanied with activation of their target genes. In the absence of USP9X, cells exhibited an epithelial-to-mesenchymal transition phenotype, acquired anchorage-independent growth in soft agar, and led to enlarged, disorganized, three-dimensional acini. YAP/TAZ target gene activation in response to USP9X knockdown was suppressed by knockdown of YAP, TAZ, and TEAD2. Deletion of USP9X in mouse embryonic fibroblasts resulted in significant downregulation of LATS. Furthermore, USP9X protein expression correlated positively with LATS but negatively with YAP/TAZ in pancreatic cancer tissues as well as pancreatic and breast cancer cell lines. Overall, these results strongly indicate that USP9X potentiates LATS kinase to suppress tumor growth. Cancer Res 77(18) 4921–33. ©2017 AACR.
On the conservation of function of the Drosophila Fat facets deubiquitinating enzyme and Fam, its mouse homolog
Publisher: Springer Science and Business Media LLC
Date: 21-11-2000
Abstract: Fat facets is a Drosophila deubiquitinating enzyme required for eye development and early embryogenesis. Genetic evidence suggests that Fat facets deubiquitinates and thereby prevents the proteasomal degradation of specific substrates. The Drosophila Liquid facets protein is implicated as the critical substrate of Fat facets in the eye. A mouse homolog of Fat facets, called Fam, has been identified. The results of biochemical experiments implicate two different proteins, Af-6 and beta-catenin, as substrates for Fam. Here, the functional relationship between Fat facets and Fam is explored. We show that Fam can substitute for Fat facets in all of its essential functions in Drosophila. In addition, we tested the hypothesis that Canoe and Armadillo, the Drosophila homologs of Af-6 and beta-catenin, respectively, are important substrates for Fat facets in the Drosophila eye. We found no genetic evidence to support a role for either Canoe or Armadillo in the essential Fat facets pathways in Drosophila eye development. The significance of these results is discussed in light of the biochemical experiments that suggest that Af-6 and beta-catenin are substrates of Fam.
Spermatogonial deubiquitinase USP9X is essential for proper spermatogenesis in mice
Publisher: Bioscientifica
Date: 08-2017
DOI: 10.1530/REP-17-0184
Abstract: USP9X (ubiquitin-specific peptidase 9, X chromosome) is the mammalian orthologue of Drosophila deubiquitinase fat facets that was previously shown to regulate the maintenance of the germ cell lineage partially through stabilizing Vasa, one of the widely conserved factors crucial for gametogenesis. Here, we demonstrate that USP9X is expressed in the gonocytes and spermatogonia in mouse testes from newborn to adult stages. By using Vasa-Cre mice, germ cell-specific conditional deletion of Usp9x from the embryonic stage showed no abnormality in the developing testes by 1 week and no appreciable defects in the undifferentiated and differentiating spermatogonia at postnatal and adult stages. Interestingly, after 2 weeks, Usp9x -null spermatogenic cells underwent apoptotic cell death at the early spermatocyte stage, and then, caused subsequent aberrant spermiogenesis, which resulted in a complete infertility of Usp9x conditional knockout male mice. These data provide the first evidence of the crucial role of the spermatogonial USP9X during transition from the mitotic to meiotic phases and/or maintenance of early meiotic phase in Usp9x conditional knockout testes.
Comprehensive assessment of genetic sequence variants in the antioxidant 'master regulator' Nrf2 in idiopathic parkinson's disease
Publisher: Public Library of Science (PLoS)
Date: 26-05-2015
Novel Use of Cell Profiling Technology to Visualize Mitochondrial Responses of Humpback Whale Fibroblasts to Chemical Exposure
Publisher: American Chemical Society (ACS)
Date: 05-06-2023
The Ubiquitin E3 Ligase MARCH7 is Differentially Regulated by the Deubiquitylating Enzymes USP7 and USP9X
Publisher: Wiley
Date: 28-06-2008
Simple and efficient production of embryonic stem cell-embryo chimeras by coculture.
Publisher: Proceedings of the National Academy of Sciences
Date: 15-05-1993
Abstract: A method for the production of embryonic stem (ES) cell-embryo chimeras was developed that involves the simple coculture of eight-cell embryos on a lawn of ES cells. After coculture, the embryos with ES cells attached are transferred to normal embryo culture medium and allowed to develop to the blastocyst stage before reimplantation into foster mothers. Although the ES cells initially attach to the outside of the embryos, they primarily colonize the inner cell mass and its derivatives. This method results in the efficient production of chimeras with high levels of chimerism including the germ line. As embryos are handled en masse and manipulative steps are minimal, this method should greatly reduce the time and effort required to produce chimeric mice.
Evolutionary and Expression Analysis of the Zebrafish Deubiquitylating Enzyme, Usp9
Publisher: Mary Ann Liebert Inc
Date: 08-2007
Abstract: Mouse Usp9x/Fam (fat facets in mouse) and its Drosophila ortholog faf (fat facets) encode substrate-specific deubiquitylating enzymes and are essential for early embryonic development. The zebrafish (Danio rerio) is a powerful tool for studying embryonic gene expression patterns and function, and to that end, we sought to characterize the zebrafish Usp9 ortholog. Zebrafish usp9 was identified from database searches, and the predicted Usp9 protein is very highly conserved in mouse (90% identical and 94% similar) over its entire length. Phylogenetic analysis indicated that vertebrate Usp9s are highly clustered and separate from the USP9Y and Drosophila forms. We examined the developmental expression of usp9 from fertilization to 2 days postfertilization. usp9 is initially expressed ubiquitously but later restricted to the cephalic central nervous system, the developing lens, distal tips of the pectoral fin bud, and migrating endoderm. The extraordinary level of conservation between the mouse and zebrafish genes, coupled with equivalent expression patterns, makes zebrafish an appropriate complementary system for the study of usp9 in development.
Deubiquitylating enzyme, USP 9X, regulates proliferation of cells of head and neck cancer lines
Publisher: Wiley
Date: 04-07-2016
DOI: 10.1111/CPR.12273
The deubiquitinating enzyme Fam interacts with and stabilizes β-catenin
Publisher: Wiley
Date: 12-1999
DOI: 10.1046/J.1365-2443.1999.00297.X
Abstract: In the ubiquitin-proteasome pathway, the ubiquitinated substrates either undergo degradation by the proteasome or stabilization through the action of the deubiquitinating enzyme. We have previously found that the deubiquitinating enzyme Fam is colocalized with AF-6, one of the effectors of the Ras small GTPase, at cell-cell contact sites in epithelial cells and interacts with AF-6 in vivo and in vitro. Fam has deubiquitinating activity in vitro and prevents the ubiquitination of AF-6 in intact cells. The degradation of beta-catenin, which accumulates at the cell-cell contact sites as a cadherin/catenin complex, is thought to be regulated by the ubiquitin-proteasome pathway. These observations prompted us to examine the possible Fam regulation of the stabilization of beta-catenin. We found that Fam interacted with beta-catenin both in vivo and in vitro. The Fam-binding site of beta-catenin mapped to the region close to the APC or Axin-binding site of beta-catenin. Over-expression of Fam in mouse L cells resulted in an elevation of beta-catenin levels and in an elongation of the half-life of beta-catenin. In these L cells, Fam was colocalized with beta-catenin at the dot-like structures in the cytoplasm. These results indicate that Fam interacts with and stabilizes beta-catenin in vivo, presumably through the deubiquitination of beta-catenin.
Identification of a Deubiquitinating Enzyme as a Novel AGS3-Interacting Protein
Publisher: Public Library of Science (PLoS)
Date: 17-03-2010
Nrf2: a modulator of Parkinson’s disease?
Publisher: Springer Science and Business Media LLC
Date: 04-05-2016
DOI: 10.1007/S00702-016-1563-0
Abstract: Parkinson's disease (PD) is a complex multifactorial disorder that has been associated with the processes of oxidative stress. In the absence of curative therapies, modification of the neurodegenerative process-including the manipulation of endogenous antioxidant pathways-is the focus of intensive research. Recently, genetic and pharmacological accretion of the transcription factor, and phase II antioxidant 'master regulator' Nrf2, has shown to demonstrably mitigate the toxic neuronal effects of parkinsonian agents such as MPP(+), rotenone, and hydrogen peroxide in vitro and in vivo. Furthermore, baseline genetic variability in Nrf2-dependant pathways may promote neuronal susceptibility to exogenous agents and correlate with PD onset within certain populations. While contemporary evidence directly implicating Nrf2 in the pathogenesis of PD is not conclusive and likely contingent upon the evaluation of complex interacting factors-including genetic variation and a history of environmental exposures-it remains a promising target for therapeutic benefit in the modulation of oxidative stress.
Proteomic profiling of idiopathic Parkinson's disease primary patient cells by SWATH-MS
Publisher: Wiley
Date: 07-06-2022
Abstract: Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. It is generally diagnosed clinically after the irreversible loss of dopaminergic neurons and no general biomarkers currently exist. To gain insight into the underlying cellular causes of PD we aimed to quantify the proteomic differences between healthy control and PD patient cells. Sequential Window Acquisition of all THeoretical Mass Spectra was performed on primary cells from healthy controls and PD patients. In total, 1948 proteins were quantified and 228 proteins were significantly differentially expressed in PD patient cells. In PD patient cells, we identified seven significantly increased proteins involved in the unfolded protein response (UPR) and focused on cells with high and low amounts of PDIA6 and HYOU1. We discovered that PD patients with high amounts of PDIA6 and HYOU1 proteins were more sensitive to endoplasmic reticulum stress, in particular to tunicamycin. Data is available via ProteomeXchange with identifier PXD030723. This data from primary patient cells has uncovered a critical role of the UPR in patients with PD and may provide insight to the underlying cellular dysfunctions in these patients.
Seizures Are Regulated by Ubiquitin-specific Peptidase 9 X-linked (USP9X), a De-Ubiquitinase
Publisher: Public Library of Science (PLoS)
Date: 12-03-2015
NRF2 Activation Restores Disease Related Metabolic Deficiencies in Olfactory Neurosphere-Derived Cells from Patients with Sporadic Parkinson's Disease
Publisher: Public Library of Science (PLoS)
Date: 07-2011
De Novo Loss-of-Function Mutations in USP9X Cause a Female-Specific Recognizable Syndrome with Developmental Delay and Congenital Malformations
Publisher: Elsevier BV
Date: 02-2016
USP9X Enhances the Polarity and Self-Renewal of Embryonic Stem Cell-derived Neural Progenitors
Publisher: American Society for Cell Biology (ASCB)
Date: 04-2009
Abstract: The substrate-specific deubiquitylating enzyme USP9X is a putative “stemness” gene expressed in many progenitor cell populations. To test its function in embryonic stem cell-derived neural progenitor/stem cells, we expressed USP9X from a Nestin promoter. Elevated USP9X levels resulted in two phenomena. First, it produced a dramatically altered cellular architecture wherein the majority ( %) of neural progenitors was arranged into radial clusters. These progenitors expressed markers of radial glial cells and were highly polarized with adherens junction proteins (N-cadherin, β-catenin, and AF-6) and apical markers (Prominin1, atypical protein kinase C-ζ) as well as Notch, Numb, and USP9X itself, concentrated at the center. The cluster centers were also devoid of nuclei and so resembled the apical end-feet of radial progenitors in the neural tube. Second, USP9X overexpression caused a fivefold increase in the number of radial progenitors and neurons, in the absence of exogenous growth factors. 5-Bromo-2′-deoxyuridine labeling, as well as the examination of the brain lipid-binding protein:βIII-tubulin ratio, indicated that nestin-USP9X enhanced the self-renewal of radial progenitors but did not block their subsequent differentiation to neurons and astrocytes. nestin-USP9X radial progenitors reformed clusters after passage as single cells, whereas control cells did not, suggesting it aids the establishment of polarity. We propose that USP9X-induced polarization of these neural progenitors results in their radial arrangement, which provides an environment conducive for self-renewal.
Surface coatings of ZnO nanoparticles mitigate differentially a host of transcriptional, protein and signalling responses in primary human olfactory cells
Publisher: Springer Science and Business Media LLC
Date: 2013
Genes and functions: trapping and targeting in embryonic stem cells
Publisher: Elsevier BV
Date: 16-12-1992
DOI: 10.1016/0304-419X(92)90016-R
Abstract: The theoretical consequences of different hypotheses of the mechanism of precipitin reactions have been evaluated by means of computer simulation. It has been found that the formation of compositionally different complexes in different antigen/antibody mixtures provides a valid explanation of the zoning phenomenon, but this concept fails to explain the absence of free antigen and of antigen in soluble complexes at the point of maximum percipitation. It is found that the following hypothesis provides an improved qualitative and quantitative explanation of percipitin reactions. In the first stage of the total reaction a series of compositionally different complexes is formed. As the second stage of the total reaction two kinds of processes are proposed. Inherently insoluble complexes precipitate causing the remaining soluble complexes to participate in mutual rearrangements to re-establish a new state of equilibrium in the supernatant. The inherently insoluble complexes, moreover, create a hydrophobic phase, distinct from the supernatant and cause the remaining otherwise soluble complexes to distribute themselves between the two phases according to a partition coefficient. A mathematical apparatus to study the consequences of this hypothesis is presented, and it is demonstrated that the features of precipitin curves can be explained nearly completely this way.
A close correlation in the expression patterns of Af-6 and Usp9x in Sertoli and granulosa cells of mouse testis and ovary
Publisher: Bioscientifica
Date: 11-2004
DOI: 10.1530/REP.1.00060
Abstract: Usp9x, an X-linked deubiquitylating enzyme, is stage dependently expressed in the supporting cells (i.e. Sertoli cells and granulosa cells) and germ cells during mouse gametogenesis. Af-6, a cell junction protein, has been identified as a substrate of Usp9x, suggesting a possible association between Usp9x and Af-6 in spermatogenesis and oogenesis. In this study, we examined the expression pattern of Af-6 and Usp9x and their intracellular localization in testes and ovaries of mice treated with or without pregnant mare serum gonadotropin (PMSG), an FSH-like hormone. In both testes and ovaries, Af-6 expression was predominantly observed in supporting cells, as well as in steroidogenic cells, but not in any germ cells. In Sertoli cells, Af-6 was continuously expressed throughout postnatal and adult stages, where both Af-6 and Usp9x were enriched at the sites of Sertoli–Sertoli and Sertoli–spermatid junctions especially at stages XI–VI. In the granulosa cells, Af-6, as well as Usp9x, was highly expressed in primordial and primary follicles, but its expression rapidly decreased after the late-secondary follicle stage. Interestingly, in PMSG-treated mice, the expression levels of Af-6 and Usp9x were synchronously enhanced, slightly in Sertoli cells and strongly in granulosa cells of the late-secondary and Graafian follicles. Such closely correlated expression patterns between Af-6 and Usp9x clearly suggest that Af-6 may be deubiquitylated by Usp9x in both Sertoli and granulosa cells. It further suggests that the post-translational regulation of Af-6 by Usp9x may be one potential pathway to control the cell adhesion dynamics in mammalian gametogenesis.
Loss of Usp9x Disrupts Cortical Architecture, Hippocampal Development and TGF beta-Mediated Axonogenesis
Publisher: Public Library of Science (PLoS)
Date: 05-07-2013
NMR Fingerprints of the Drug-like Natural-Product Space Identify Iotrochotazine A: A Chemical Probe to Study Parkinson's Disease
Publisher: Wiley
Date: 15-04-2014
A patient-derived stem cell model of hereditary spastic paraplegia with SPAST mutations
Publisher: The Company of Biologists
Date: 2013
DOI: 10.1242/DMM.010884
Abstract: Hereditary spastic paraplegia (HSP) leads to progressive gait disturbances with lower limb muscle weakness and spasticity. Mutations in SPAST are a major cause of adult-onset, autosomal-dominant HSP. Spastin, the protein encoded by SPAST, is a microtubule-severing protein that is enriched in the distal axon of corticospinal motor neurons which degenerate in HSP patients. Animal and cell models have identified functions of spastin and mutated spastin but these models lack the gene dosage, mutation variability and genetic background that characterize patients with the disease. In this study, this genetic variability is encompassed by comparing neural progenitor cells derived from biopsies of the olfactory mucosa from healthy controls with similar cells from HSP patients with SPAST mutations, in order to identify cell functions altered in HSP. Patient-derived cells were similar to control-derived cells in proliferation and multiple metabolic functions but had major dysregulation of gene expression, with 57% of all mRNA transcripts affected, including many associated with microtubule dynamics. Compared to control cells, patient-derived cells had 50% spastin, 50% acetylated α-tubulin and 150% stathmin, a microtubule-destabilising enzyme. Patient-derived cells were smaller than control cells. They had altered intracellular distributions of peroxisomes and mitochondria and they had slower moving peroxisomes. These results suggest that patient-derived cells might compensate for reduced spastin, but their increased stathmin expression reduced stabilised microtubules and altered organelle trafficking. Sub-nanomolar concentrations of the microtubule-binding drugs, paclitaxel and vinblastine, increased acetylated α-tubulin levels in patient cells to control levels, indicating the utility of this cell model for screening other candidate compounds for drug therapies.
Mutations in USP9X are associated with X-linked intellectual disability and disrupt neuronal cell migration and growth.
Publisher: Elsevier BV
Date: 03-2014
USP9x-mediated deubiquitination of EFA6 regulates de novo tight junction assembly
Publisher: Wiley
Date: 25-03-2010
The Ubiquitin System: a Regulatory Hub for Intellectual Disability and Autism Spectrum Disorder
Publisher: Springer Science and Business Media LLC
Date: 23-01-2020
DOI: 10.1007/S12035-020-01881-X
Abstract: Intellectual disability (ID) and autism spectrum disorder (ASD) are two of the most common neurodevelopmental disorders. Both disorders are extremely heterogenous, and only ~ 40% of reported cases have so far been attributed to genetic mutations. Of the many cellular processes that are affected, the ubiquitin system (UbS) is of particular relevance in that it can rapidly regulate multiple signaling cascades simultaneously. The UbS is a post-translational modification process that revolves around the covalent attachment of a ubiquitin moiety to a substrate, thereby influencing different elements of protein biology, including trafficking, signal transduction, and degradation. Importantly, the UbS has been implicated in regulating multiple pathophysiological pathways related to ASD and ID. This review will discuss how the UbS acts as major signaling hub in the pathogenesis of ASD and ID, raising the prospect of treating broader patient cohorts by targeting the UbS as a common point of convergence of various mutations.
Kororamide B, a brominated alkaloid from the bryozoan Amathia tortuosa and its effects on Parkinson's disease cells
Publisher: Elsevier BV
Date: 10-2015
Identification of Ubiquitin-specific Protease 9X (USP9X) as a Deubiquitinase Acting on Ubiquitin-Peroxin 5 (PEX5) Thioester Conjugate
Publisher: Elsevier BV
Date: 04-2012
Riding the DUBway: regulation of protein trafficking by deubiquitylating enzymes
Publisher: Rockefeller University Press
Date: 15-05-2006
Abstract: Ubiquitylation is a key regulator of protein trafficking, and much about the functions of ubiquitin ligases, which add ubiquitin to substrates in this regulation, has recently come to light. However, a clear understanding of ubiquitin-dependent protein localization cannot be achieved without knowledge of the role of deubiquitylating enzymes (DUBs). DUBs, by definition, function downstream in ubiquitin pathways and, as such, have the potential to be the final editors of protein ubiquitylation status, thus determining substrate fate. This paper assimilates the current evidence concerning the substrates and activities of DUBs that regulate protein trafficking.
DNA methylation in schizophrenia in different patient-derived cell types
Publisher: Springer Science and Business Media LLC
Date: 23-01-2017
DOI: 10.1038/S41537-016-0006-0
Abstract: DNA methylation of gene promoter regions represses transcription and is a mechanism via which environmental risk factors could affect cells during development in in iduals at risk for schizophrenia. We investigated DNA methylation in patient-derived cells that might shed light on early development in schizophrenia. Induced pluripotent stem cells may reflect a “ground state” upon which developmental and environmental influences would be minimal. Olfactory neurosphere-derived cells are an adult-derived neuro-ectodermal stem cell modified by developmental and environmental influences. Fibroblasts provide a non-neural control for life-long developmental and environmental influences. Genome-wide profiling of DNA methylation and gene expression was done in these three cell types from the same in iduals. All cell types had distinct, statistically significant schizophrenia-associated differences in DNA methylation and linked gene expression, with Gene Ontology analysis showing that the differentially affected genes clustered in networks associated with cell growth, proliferation, and movement, functions known to be affected in schizophrenia patient-derived cells. Only five gene loci were differentially methylated in all three cell types. Understanding the role of epigenetics in cell function in the brain in schizophrenia is likely to be complicated by similar cell type differences in intrinsic and environmentally induced epigenetic regulation.
Gene knock-out technology: a methodological overview for the interested novice
Publisher: Elsevier BV
Date: 04-1995
DOI: 10.1016/0022-1759(95)00017-5
Abstract: Gene targeting by homologous recombination is a powerful technique, generating mouse strains with defined mutations in their genome. These genetically modified, 'designer' animals allow us for the first time to ask simple questions about elaborate and complex biological systems. Dissecting the function of in idual components of the immune system is a perfect application of this technology. Although the techniques involved in the generation of gene knock-out mice are increasingly well defined, to many immunologists the language and concepts are confusing. This review presents the essentials of the technology in a form digestible by the non-expert.
Disease-specific, neurosphere-derived cells as models for brain disorders
Publisher: The Company of Biologists
Date: 28-10-2010
DOI: 10.1242/DMM.005447
Abstract: There is a pressing need for patient-derived cell models of brain diseases that are relevant and robust enough to produce the large quantities of cells required for molecular and functional analyses. We describe here a new cell model based on patient-derived cells from the human olfactory mucosa, the organ of smell, which regenerates throughout life from neural stem cells. Olfactory mucosa biopsies were obtained from healthy controls and patients with either schizophrenia, a neurodevelopmental psychiatric disorder, or Parkinson’s disease, a neurodegenerative disease. Biopsies were dissociated and grown as neurospheres in defined medium. Neurosphere-derived cell lines were grown in serum-containing medium as adherent monolayers and stored frozen. By comparing 42 patient and control cell lines we demonstrated significant disease-specific alterations in gene expression, protein expression and cell function, including dysregulated neurodevelopmental pathways in schizophrenia and dysregulated mitochondrial function, oxidative stress and xenobiotic metabolism in Parkinson’s disease. The study has identified new candidate genes and cell pathways for future investigation. Fibroblasts from schizophrenia patients did not show these differences. Olfactory neurosphere-derived cells have many advantages over embryonic stem cells and induced pluripotent stem cells as models for brain diseases. They do not require genetic reprogramming and they can be obtained from adults with complex genetic diseases. They will be useful for understanding disease aetiology, for diagnostics and for drug discovery.
Region-Specific Protein Abundance Changes in the Brain of MPTP-Induced Parkinson’s Disease Mouse Model
Publisher: American Chemical Society (ACS)
Date: 15-02-2010
DOI: 10.1021/PR901024Z
Doublecortin interacts with the ubiquitin protease DFFRX, which associates with microtubules in neuronal processes
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.MCN.2004.09.005
Abstract: Doublecortin (DCX) is a microtubule-associated protein involved in neuronal migration, which causes X-linked lissencephaly and subcortical laminar heterotopia (SCLH) when mutated. Here we show that DCX interacts with the ubiquitin-specific protease Drosophila fat facets related on X chromosome (DFFRX). This interaction was confirmed by targeted mutagenesis, colocalization, and immunoprecipitation studies. DFFRX is thought to deubiquitinate specific substrates including beta-catenin, preventing their degradation by the proteasome. Interestingly, unlike beta-catenin, no ubiquitinated forms of DCX could be detected, and indeed we show that DCX interacts with a novel recognition domain in DFFRX, located outside of its catalytic site. We also show that DFFRX associates with microtubules at specific subcellular compartments, including those enriched in DCX. These results thus suggest that in addition to vesicular trafficking, DCX may play a role in the regulation of cell adhesion via its interaction with DFFRX in migrating and differentiating neurons.
Meeting the Challenge 2: Identification of Potential Chemical Probes for Parkinson’s Disease from Ligusticum chuanxiong Hort Using Cytological Profiling
Publisher: American Chemical Society (ACS)
Date: 26-08-2022
DOI: 10.1021/ACSCHEMNEURO.1C00820
Abstract: Traditional Chinese medicine (TCM) has been around for thousands of years and is increasingly gaining popularity in the Western world to treat various complex disorders including the incurable neurodegenerative condition, Parkinson's Disease (PD). One of the many directions in recent studies of PD is utilizing the phenotypic assay, or cytological profiling, to evaluate the phenotypic changes of PD-implicated cellular components in patient-derived olfactory neuroepithelial (hONS) cells, upon treating the cells with extracts or pure compounds. To obtain small molecules for studies utilizing PD phenotyping assays,
Co-localization of FAM and AF-6, the mammalian homologues of Drosophila faf and canoe, in mouse eye development.
Publisher: Elsevier BV
Date: 03-2000
The Vps35 D620N mutation linked to Parkinson's disease disrupts the cargo sorting function of retromer.
Publisher: Wiley
Date: 14-11-2014
DOI: 10.1111/TRA.12136
Abstract: The retromer is a trimeric cargo-recognition protein complex composed of Vps26, Vps29 and Vps35 associated with protein trafficking within endosomes. Recently, a pathogenic point mutation within the Vps35 subunit (D620N) was linked to the manifestation of Parkinson's disease (PD). Here, we investigated details underlying the molecular mechanism by which the D620N mutation in Vps35 modulates retromer function, including examination of retromer's subcellular localization and its capacity to sort cargo. We show that expression of the PD-linked Vps35 D620N mutant redistributes retromer-positive endosomes to a perinuclear subcellular localization and that these endosomes are enlarged in both model cell lines and fibroblasts isolated from a PD patient. Vps35 D620N is correctly folded and binds Vps29 and Vps26A with the same affinity as wild-type Vps35. While PD-linked point mutant Vps35 D620N interacts with the cation-independent mannose-6-phosphate receptor (CI-M6PR), a known retromer cargo, we find that its expression disrupts the trafficking of cathepsin D, a CI-M6PR ligand and protease responsible for degradation of α-synuclein, a causative agent of PD. In summary, we find that the expression of Vps35 D620N leads to endosomal alterations and trafficking defects that may partly explain its action in PD.
Loss of Usp9x disrupts cell adhesion, and components of the Wnt and Notch signaling pathways in neural progenitors
Publisher: Springer Science and Business Media LLC
Date: 14-08-2017
DOI: 10.1038/S41598-017-05451-5
Abstract: Development of neural progenitors depends upon the coordination of appropriate intrinsic responses to extrinsic signalling pathways. Here we show the deubiquitylating enzyme, Usp9x regulates components of both intrinsic and extrinsic fate determinants. Nestin - cre mediated ablation of Usp9x from embryonic neural progenitors in vivo resulted in a transient disruption of cell adhesion and apical-basal polarity and, an increased number and ectopic localisation of intermediate neural progenitors. In contrast to other adhesion and polarity proteins, levels of β-catenin protein, especially S33/S37/T41 phospho-β-catenin, were markedly increased in Usp9x −/ Y embryonic cortices. Loss of Usp9x altered composition of the β-catenin destruction complex possibly impeding degradation of S33/S37/T41 phospho-β-catenin. Pathway analysis of transcriptomic data identified Wnt signalling as significantly affected in Usp9x −/ Y embryonic brains. Depletion of Usp9x in cultured human neural progenitors resulted in Wnt-reporter activation. Usp9x also regulated components of the Notch signalling pathway. Usp9x co-localized and associated with both Itch and Numb in embryonic neocortices. Loss of Usp9x led to decreased Itch and Numb levels, and a concomitant increase in levels of the Notch intracellular domain as well as, increased expression of the Notch target gene Hes5. Therefore Usp9x modulates and potentially coordinates multiple fate determinants in neural progenitors.
A Grand Challenge. 2. Phenotypic Profiling of a Natural Product Library on Parkinson's Patient-Derived Cells
Publisher: American Chemical Society (ACS)
Date: 22-07-2016
DOI: 10.1021/ACS.JNATPROD.6B00258
Abstract: Harnessing the inherent biological relevance of natural products requires a method for the recognition of biological effects that may subsequently lead to the discovery of particular targets. An unbiased multidimensional profiling method was used to examine the activities of natural products on primary cells derived from a Parkinson's disease patient. The biological signature of 482 natural products was examined using multiparametric analysis to investigate known cellular pathways and organelles implicated in Parkinson's disease such as mitochondria, lysosomes, endosomes, apoptosis, and autophagy. By targeting several cell components simultaneously the chance of finding a phenotype was increased. The phenotypes were then clustered using an uncentered correlation. The multidimensional phenotypic screening showed that all natural products, in our screening set, were biologically relevant compounds as determined by an observed phenotypic effect. Multidimensional phenotypic screening can predict the cellular function and subcellular site of activity of new compounds, while the cluster analysis provides correlation with compounds with known mechanisms of action. This study reinforces the value of natural products as biologically relevant compounds.
The FAM Deubiquitylating Enzyme Localizes to Multiple Points of Protein Trafficking in Epithelia, where It Associates with E-cadherin and β-catenin
Publisher: American Society for Cell Biology (ASCB)
Date: 04-2004
Abstract: Ubiquitylation is a necessary step in the endocytosis and lysosomal trafficking of many plasma membrane proteins and can also influence protein trafficking in the biosynthetic pathway. Although a molecular understanding of ubiquitylation in these processes is beginning to emerge, very little is known about the role deubiquitylation may play. Fat Facets in mouse (FAM) is substrate-specific deubiquitylating enzyme highly expressed in epithelia where it interacts with its substrate, β-catenin. Here we show, in the polarized intestinal epithelial cell line T84, FAM localized to multiple points of protein trafficking. FAM interacted with β-catenin and E-cadherin in T84 cells but only in subconfluent cultures. FAM extensively colocalized with β-catenin in cytoplasmic puncta but not at sites of cell-cell contact as well as immunoprecipitating with β-catenin and E-cadherin from a higher molecular weight complex (∼500 kDa). At confluence FAM neither colocalized with, nor immunoprecipitated, β-catenin or E-cadherin, which were predominantly in a larger molecular weight complex (∼2 MDa) at the cell surface. Overexpression of FAM in MCF-7 epithelial cells resulted in increased β-catenin levels, which localized to the plasma membrane. Expression of E-cadherin in L-cell fibroblasts resulted in the relocalization of FAM from the Golgi to cytoplasmic puncta. These data strongly suggest that FAM associates with E-cadherin and β-catenin during trafficking to the plasma membrane.
Stage- and sex-dependent expressions of Usp9x, an X-linked mouse ortholog of Drosophila Fat facets, during gonadal development and oogenesis in mice
Publisher: Elsevier BV
Date: 12-2002
DOI: 10.1016/S0925-4773(03)00098-4
Abstract: During the Drosophila oogenic processes, Fat facets (Faf), an ubiquitin-specific protease essential for normal development of oocyte and eye, becomes localized at the posterior pole and is incorporated into the pole cells. This is dependent on Oskar, a key factor for pole cell determination, and suggests a role for Faf in germ cell differentiation and development. Here we show that Usp9x, an X-linked ortholog of Faf, is predominantly expressed in both germ cell and supporting cell lineages during mouse gonadal development in stage- and sex-dependent manners. Usp9x was first detected in PGCs at 10.5 days post coitum (dpc), and thereafter its expression both at mRNA and protein levels was enhanced in PGCs of both sexes at 11.5-13.5 dpc. In testis, Usp9x expression rapidly decreased to an undetectable level by 15.5 dpc and after birth to adult, no expression was found in any spermatogenic cells, except for weak expression in Sertoli cells. In the ovary, Usp9x expression in embryonic oocytes was also reduced at the newborn stage, its expression reappeared in oocytes at secondary follicle stage, and its products were highly accumulated in the cytoplasm of Graaffian follicles in adults. Although follicular epithelial cells also expressed Usp9x at a moderate level during postnatal development, its expression was downregulated from early secondary follicle stage. Thus, the present study is not only the first to demonstrate a conserved expression of fat facets in PGCs between mouse and fly, but also sex- and stage-dependent changes of a specific component of the deubiquitylation system during mammalian gonadal development.
FAM deubiquitylating enzyme is essential for preimplantation mouse embryo development.
Publisher: Elsevier BV
Date: 12-2001
Regulation of epithelial apical junctions and barrier function by Gα13
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.BBAMCR.2009.04.008
Abstract: The epithelial tight junction forms a barrier to paracellular solute movement. In this study we show that the heterotrimeric G-protein Galpha13 regulates the epithelial tight junction barrier. We generated MDCKII kidney epithelial cell lines in which the expression of an active Galpha13 mutant (Galpha13Q226L) could be induced. We demonstrated that Galpha13Q226L expression increased paracellular permeability and caused the disruption and redistribution of proteins comprising the tight junction and the adherens junction away from sites of cell contact and the appearance of basal stress fibers. The effects on the junctional proteins and the actin cytoskeleton were abrogated by the Rho kinase inhibitor Y27632 but not by the Src kinase inhibitor PP2. The Galpha13 mediated increase in permeability was also Src kinase independent but was partly dependent on Rho kinase signalling. Our data establish a link between Galpha13, Rho kinase signaling and epithelial barrier function and not only demonstrate that Galpha13 regulates epithelial apical junction properties but that it does so via signaling pathways that are distinct from the closely related protein Galpha12.
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Discovery Projects - Grant ID: DP130102400
Start Date: 2013
End Date: 12-2016
Amount: $390,000.00
Funder: Australian Research Council
View Funded ActivitySpecial Research Initiatives - Grant ID: SR0354892
Start Date: 2004
End Date: 12-2004
Amount: $40,000.00
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View Funded Activity