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A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis

Insulin promotes glucose uptake into skeletal muscle through recruitment of glucose transporter 4 (GLUT4) to the plasma membrane. Rab GTPases are molecular switches mobilizing intracellular vesicles, and Rab13 is necessary for insulin-regulated GLUT4–vesicle exocytic translocation in muscle cells. W...

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Autores principales: Sun, Yi, Jaldin-Fincati, Javier, Liu, Zhi, Bilan, Philip J., Klip, Amira
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4694764/
https://www.ncbi.nlm.nih.gov/pubmed/26538022
http://dx.doi.org/10.1091/mbc.E15-05-0319
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author Sun, Yi
Jaldin-Fincati, Javier
Liu, Zhi
Bilan, Philip J.
Klip, Amira
author_facet Sun, Yi
Jaldin-Fincati, Javier
Liu, Zhi
Bilan, Philip J.
Klip, Amira
author_sort Sun, Yi
collection PubMed
description Insulin promotes glucose uptake into skeletal muscle through recruitment of glucose transporter 4 (GLUT4) to the plasma membrane. Rab GTPases are molecular switches mobilizing intracellular vesicles, and Rab13 is necessary for insulin-regulated GLUT4–vesicle exocytic translocation in muscle cells. We show that Rab13 engages the scaffold protein MICAL-L2 in this process. RNA interference–mediated knockdown of MICAL-L2 or truncated MICAL-L2 (MICAL-L2-CT) impaired insulin-stimulated GLUT4 translocation. Insulin increased Rab13 binding to MICAL-L2, assessed by pull down and colocalization under confocal fluorescence and structured illumination microscopies. Association was also visualized at the cell periphery using TIRF microscopy. Insulin further increased binding of MICAL-L2 to α-actinin-4 (ACTN4), a protein involved in GLUT4 translocation. Rab13, MICAL-L2, and ACTN4 formed an insulin-dependent complex assessed by pull down and confocal fluorescence imaging. Of note, GLUT4 associated with the complex in response to insulin, requiring the ACTN4-binding domain in MICAL-L2. This was demonstrated by pull down with distinct fragments of MICAL-L2 and confocal and structured illumination microscopies. Finally, expression of MICAL-L2-CT abrogated the insulin-dependent colocalization of Rab13 with ACTN4 or Rab13 with GLUT4. Our findings suggest that MICAL-L2 is an effector of insulin-activated Rab13, which links to GLUT4 through ACTN4, localizing GLUT4 vesicles at the muscle cell periphery to enable their fusion with the membrane.
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spelling pubmed-46947642016-03-16 A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis Sun, Yi Jaldin-Fincati, Javier Liu, Zhi Bilan, Philip J. Klip, Amira Mol Biol Cell Articles Insulin promotes glucose uptake into skeletal muscle through recruitment of glucose transporter 4 (GLUT4) to the plasma membrane. Rab GTPases are molecular switches mobilizing intracellular vesicles, and Rab13 is necessary for insulin-regulated GLUT4–vesicle exocytic translocation in muscle cells. We show that Rab13 engages the scaffold protein MICAL-L2 in this process. RNA interference–mediated knockdown of MICAL-L2 or truncated MICAL-L2 (MICAL-L2-CT) impaired insulin-stimulated GLUT4 translocation. Insulin increased Rab13 binding to MICAL-L2, assessed by pull down and colocalization under confocal fluorescence and structured illumination microscopies. Association was also visualized at the cell periphery using TIRF microscopy. Insulin further increased binding of MICAL-L2 to α-actinin-4 (ACTN4), a protein involved in GLUT4 translocation. Rab13, MICAL-L2, and ACTN4 formed an insulin-dependent complex assessed by pull down and confocal fluorescence imaging. Of note, GLUT4 associated with the complex in response to insulin, requiring the ACTN4-binding domain in MICAL-L2. This was demonstrated by pull down with distinct fragments of MICAL-L2 and confocal and structured illumination microscopies. Finally, expression of MICAL-L2-CT abrogated the insulin-dependent colocalization of Rab13 with ACTN4 or Rab13 with GLUT4. Our findings suggest that MICAL-L2 is an effector of insulin-activated Rab13, which links to GLUT4 through ACTN4, localizing GLUT4 vesicles at the muscle cell periphery to enable their fusion with the membrane. The American Society for Cell Biology 2016-01-01 /pmc/articles/PMC4694764/ /pubmed/26538022 http://dx.doi.org/10.1091/mbc.E15-05-0319 Text en © 2016 Sun et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology.
spellingShingle Articles
Sun, Yi
Jaldin-Fincati, Javier
Liu, Zhi
Bilan, Philip J.
Klip, Amira
A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis
title A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis
title_full A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis
title_fullStr A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis
title_full_unstemmed A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis
title_short A complex of Rab13 with MICAL-L2 and α-actinin-4 is essential for insulin-dependent GLUT4 exocytosis
title_sort complex of rab13 with mical-l2 and α-actinin-4 is essential for insulin-dependent glut4 exocytosis
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4694764/
https://www.ncbi.nlm.nih.gov/pubmed/26538022
http://dx.doi.org/10.1091/mbc.E15-05-0319
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