News Column

Reports Outline Proinsulin Study Results from Cell Biology Program

June 17, 2014

By a News Reporter-Staff News Editor at Life Science Weekly -- A new study on Peptide Proteins is now available. According to news reporting from Toronto, Canada, by NewsRx journalists, research stated, "Rab-GTPases are important molecular switches regulating intracellular vesicle traffic, and we recently showed that Rab8A and Rab13 are activated by insulin in muscle to mobilize GLUT4-containing vesicles to the muscle cell surface. Here we show that the unconventional motor protein myosin Va (MyoVa) is an effector of Rab8A in this process."

The news correspondents obtained a quote from the research from Cell Biology Program, "In CHO-IR cell lysates, a glutathione S-transferase chimera of the cargo-binding COOH tail (CT) of MyoVa binds Rab8A and the related Rab10, but not Rab13. Binding to Rab8A is stimulated by insulin in a phosphatidylinositol 3-kinase-dependent manner, whereas Rab10 binding is insulin insensitive. MyoVa-CT preferentially binds GTP-locked Rab8A. Full-length green fluorescent protein (GFP)-MyoVa colocalizes with mCherry-Rab8A in perinuclear small puncta, whereas GFP-MyoVa-CT collapses the GTPase into enlarged perinuclear depots. Further, GFP-MyoVa-CT blocks insulin-stimulated translocation of exofacially myc-tagged GLUT4 to the surface of muscle cells. Mutation of amino acids in MyoVa-CT predicted to bind Rab8A abrogates both interaction with Rab8A (not Rab10) and inhibition of insulin-stimulated GLUT4myc translocation. Of importance, small interfering RNA-mediated MyoVa silencing reduces insulin-stimulated GLUT4myc translocation. Rab8A colocalizes with GLUT4 in perinuclear but not submembrane regions visualized by confocal total internal reflection fluorescence microscopy."

According to the news reporters, the research concluded: "Hence insulin signaling to the molecular switch Rab8A connects with the motor protein MyoVa to mobilize GLUT4 vesicles toward the muscle cell plasma membrane."

For more information on this research see: Myosin Va mediates Rab8A-regulated GLUT4 vesicle exocytosis in insulin-stimulated muscle cells. Molecular Biology of the Cell, 2014;25(7):1159-70 (see also Peptide Proteins).

Our news journalists report that additional information may be obtained by contacting Y. Sun, Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada. Additional authors for this research include T.T. Chiu, K.P. Foley, P.J. Bilan and A. Klip.

Keywords for this news article include: Canada, Toronto, Ontario, Proinsulin, Muscle Cells, Nanotechnology, Peptide Hormones, Peptide Proteins, Molecular Switches, Emerging Technologies, North and Central America, Green Fluorescent Protein.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC

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Source: Life Science Weekly

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