Vincent Chui

Simon Fraser University, Burnaby, British Columbia, Canada

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Publications (2)2.18 Total impact

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    ABSTRACT: Adducin is a ubiquitously expressed actin- and spectrin-binding protein involved in cytoskeleton organization, and is regulated through phosphorylation of the myristoylated alanine-rich C-terminal kinase (MARCKS)-homology domain by protein kinase C (PKC). We have previously shown that the Drosophila adducin, Hu-li tai shao (Hts), plays a role in larval neuromuscular junction (NMJ) growth. Here, we find that the predominant isoforms of Hts at the NMJ contain the MARCKS-homology domain, which is important for interactions with Discs large (Dlg) and phosphatidylinositol 4,5-bisphosphate (PIP2). Through the use of Proximity Ligation Assay (PLA), we show that the adducin-like Hts isoforms are in complexes with Dlg and PIP2 at the NMJ. We provide evidence that Hts promotes the phosphorylation and delocalization of Dlg at the NMJ through regulation of the transcript distribution of the PAR-1 and CaMKII kinases in the muscle. We also show that Hts interactions with Dlg and PIP2 are impeded through phosphorylation of the MARCKS-homology domain. These results are further evidence that Hts is a signaling-responsive regulator of synaptic plasticity in Drosophila. © 2014. Published by The Company of Biologists Ltd.
    11/2014; 3(12). DOI:10.1242/bio.20148342
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    ABSTRACT: The Rho family small GTPases Rho, Rac, and Cdc42 regulate cell shape and motility through the actin cytoskeleton. These proteins cycle between a GTP-bound "on" state and a GDP-bound "off" state and are negatively regulated by GTPase-activating proteins (GAPs), which accelerate the small GTPase's intrinsic hydrolysis of bound GTP to GDP. Drosophila RhoGAP68F is similar to the mammalian protein p50RhoGAP/Cdc42GAP, which exhibits strong GAP activity toward Cdc42. We find that, despite the strong similarities between RhoGAP68F and p50RhoGAP/Cdc42GAP, RhoGAP68F is most effective as a GAP for RhoA. These in vitro data are supported by the in vivo analysis of mutants in RhoGAP68F. We demonstrate through the characterization of two alleles of the RhoGAP68F gene that RhoGAP68F participates in gastrulation of the embryo, a morphogenetic event driven by cell constriction that involves RhoA signaling. We propose that RhoGAP68F functions as a regulator of RhoA signaling during gastrulation.
    Development Genes and Evolution 10/2006; 216(9):543-50. DOI:10.1007/s00427-006-0067-6 · 2.18 Impact Factor

Publication Stats

9 Citations
2.18 Total Impact Points

Institutions

  • 2006–2014
    • Simon Fraser University
      • • Department of Biomedical Physiology and Kinesiology
      • • Department of Molecular Biology and Biochemistry
      Burnaby, British Columbia, Canada