ORCID Profile
0000-0003-1905-6023
Current Organisation
University of South Australia
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Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-08-2023
Abstract: Piezo channels are critical cellular sensors of mechanical forces. Despite their large size, ubiquitous expression, and irreplaceable roles in an ever-growing list of physiological processes, few Piezo channel–binding proteins have emerged. In this work, we found that MyoD (myoblast determination)–family inhibitor proteins (MDFIC and MDFI) are PIEZO1/2 interacting partners. These transcriptional regulators bind to PIEZO1/2 channels, regulating channel inactivation. Using single-particle cryogenic electron microscopy, we mapped the interaction site in MDFIC to a lipidated, C-terminal helix that inserts laterally into the PIEZO1 pore module. These Piezo-interacting proteins fit all the criteria for auxiliary subunits, contribute to explaining the vastly different gating kinetics of endogenous Piezo channels observed in many cell types, and elucidate mechanisms potentially involved in human lymphatic vascular disease.
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.FSI.2012.03.002
Abstract: Peroxiredoxin 1 (Prx 1), also known as natural killer enhancing factor A (NKEF A), has been implicated in the immune response of both mammals and fish. Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a significant problem for the Atlantic salmon (Salmo salar L.) aquaculture industry based in Tasmania, Australia. Here we have cloned and functionally characterized a Prx 1 open reading frame (ORF) from Atlantic salmon liver and shown that Prx 1 gene expression was down-regulated in the gills of Atlantic salmon displaying symptoms of AGD. The Prx 1 ORF encoded all of the residues and motifs characteristic of typical 2-Cys Prx proteins from eukaryotes and the recombinant protein expressed in Escherichia coli catalyzed thioredoxin (Trx)-dependent reduction of H(2)O(2), cumene hydroperoxide (CuOOH) and t-butyl hydroperoxide (t-bOOH) with K(m) values of 122, 77 and 91 μM, respectively, confirming that it was a genuine 2-Cys Prx. The recombinant protein also displayed a double displacement reaction mechanism and a catalytic efficiency (k(cat)/K(m)) with H(2)O(2) of 1.5 × 10(5) M(-1) s(-1) which was consistent with previous reports for the 2-Cys Prx family of proteins. This is the first time that a Prx 1 protein has been functionally characterized from any fish species and it paves the way for further investigation of this important 2-Cys Prx family member in fish.
Publisher: American Society for Clinical Investigation
Date: 12-12-2018
DOI: 10.1172/JCI78888
Publisher: Elsevier BV
Date: 06-2010
DOI: 10.1016/J.CBPB.2010.02.011
Abstract: Peroxiredoxins (Prxs, EC: 1.11.1.15) are cysteine-dependent peroxidases proposed to function as antioxidant enzymes and also in H2O2-mediated cell signaling. They have been well characterized in yeast, mammals, protists and bacteria but not yet in fish. Here we describe the cloning and functional characterization of a Prx 2 cDNA from southern bluefin tuna (SBT, Thunnus maccoyii), an important aquaculture species in South Australia. The SBT Prx sequence was closely related (76-92% identical) to Prx 1 and 2 sequences from other fish and mammals and phylogenetic analyses showed that it was most likely a Prx 2. The deduced amino acid sequence contained the peroxidatic and resolving Cys residues characteristic of typical 2-Cys Prx proteins from all kingdoms of life. It also contained the GGLG motif associated with the sensitivity of eukaryotic typical 2-Cys Prx proteins to overoxidation and consequent inactivation by H2O2. When the SBT Prx 2 was expressed in E. coli, it showed thioredoxin (Trx)-dependent peroxidase activity with H2O2, cumene hydroperoxide (CuOOH) and t-butyl hydroperoxide (t-bOOH). The SBT Prx displayed Michaelis-Menten kinetics with Trx but sigmoidal kinetics with H2O2 and CuOOH. The K(m)(Trx) was 12 microM and the S(0.5) values for H2O2 and CuOOH were 29 and 25 microM, respectively. At mM concentrations of H2O2, SBT Prx progressively lost its peroxidase activity as has been observed for other eukaryotic typical 2-Cys Prx proteins. The native SBT Prx enzyme existed as a mixture of dimers, tetramers, decamers and a higher order aggregate.
Publisher: American Society for Clinical Investigation
Date: 18-05-2020
DOI: 10.1172/JCI99027
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.DEVCEL.2019.03.017
Abstract: The correct assignment of cell fate within fields of multipotent progenitors is essential for accurate tissue ersification. The first lymphatic vessels arise from pre-existing veins after venous endothelial cells become specified as lymphatic progenitors. Prox1 specifies lymphatic fate and labels these progenitors however, the mechanisms restricting Prox1 expression and limiting the progenitor pool remain unknown. We identified a zebrafish mutant that displayed premature, expanded, and prolonged lymphatic specification. The gene responsible encodes the regulator of alternative splicing, Nova2. In zebrafish and human endothelial cells, Nova2 selectively regulates pre-mRNA splicing for components of signaling pathways and phosphoproteins. Nova2-deficient endothelial cells display increased Mapk/Erk signaling, and Prox1 expression is dynamically controlled by Erk signaling. We identify a mechanism whereby Nova2-regulated splicing constrains Erk signaling, thus limiting lymphatic progenitor cell specification. This identifies the capacity of a factor that tunes mRNA splicing to control assignment of cell fate during vascular differentiation.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-03-2022
DOI: 10.1126/SCITRANSLMED.ABM4869
Abstract: Central conducting lymphatic anomaly (CCLA), characterized by the dysfunction of core collecting lymphatic vessels including the thoracic duct and cisterna chyli, and presenting as chylothorax, pleural effusions, chylous ascites, and lymphedema, is a severe disorder often resulting in fetal or perinatal demise. Although pathogenic variants in RAS/mitogen activated protein kinase (MAPK) signaling pathway components have been documented in some patients with CCLA, the genetic etiology of the disorder remains uncharacterized in most cases. Here, we identified biallelic pathogenic variants in MDFIC , encoding the MyoD family inhibitor domain containing protein, in seven in iduals with CCLA from six independent families. Clinical manifestations of affected fetuses and children included nonimmune hydrops fetalis (NIHF), pleural and pericardial effusions, and lymphedema. Generation of a mouse model of human MDFIC truncation variants revealed that homozygous mutant mice died perinatally exhibiting chylothorax. The lymphatic vasculature of homozygous Mdfic mutant mice was profoundly mispatterned and exhibited major defects in lymphatic vessel valve development. Mechanistically, we determined that MDFIC controls collective cell migration, an important early event during the formation of lymphatic vessel valves, by regulating integrin β 1 activation and the interaction between lymphatic endothelial cells and their surrounding extracellular matrix. Our work identifies MDFIC variants underlying human lymphatic disease and reveals a crucial, previously unrecognized role for MDFIC in the lymphatic vasculature. Ultimately, understanding the genetic and mechanistic basis of CCLA will facilitate the development and implementation of new therapeutic approaches to effectively treat this complex disease.
No related grants have been discovered for Drew Sutton.