The F-BAR protein CIP4 promotes GLUT4 endocytosis through bidirectional interactions with N-WASp and Dynamin-2
Autor: | Christina S. Pichot, Seth J. Corey, Yanming Feng, Robert W. Grange, Shuhei Ishikura, Robert M. Raphael, Rachel S Hicklen, Sean M. Hartig, Amira Klip, Elisabeth G. Blanchard, Kevin A. Voelker |
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Rok vydání: | 2009 |
Předmět: |
Immunoprecipitation
media_common.quotation_subject Wiskott-Aldrich Syndrome Protein Neuronal CDC42 Biology Endocytosis Cell Line Myoblasts Dynamin II Fluorescence Resonance Energy Transfer Animals Insulin Protein Isoforms RNA Small Interfering Internalization Dynamin media_common chemistry.chemical_classification Glucose Transporter Type 4 Cell Membrane Cell Biology Receptor-mediated endocytosis Flow Cytometry Cell biology Rats Cytosol chemistry Transferrin Gene Knockdown Techniques Microtubule-Associated Proteins Research Article |
Zdroj: | Journal of cell science. 122(Pt 13) |
ISSN: | 0021-9533 |
Popis: | F-BAR proteins are a newly described family of proteins with unknown physiological significance. Because F-BAR proteins, including Cdc42 interacting protein-4 (CIP4), drive membrane deformation and affect endocytosis, we investigated the role of CIP4 in GLUT4 traffic by flow cytometry in GLUT4myc-expressing L6 myoblasts (L6 GLUT4myc). L6 GLUT4myc cells express CIP4a as the predominant F-BAR protein. siRNA knockdown of CIP4 increased insulin-stimulated 14C-deoxyglucose uptake by elevating cell-surface GLUT4. Enhanced surface GLUT4 was due to decreased endocytosis, which correlated with lower transferrin internalization. Immunoprecipitation of endogenous CIP4 revealed that CIP4 interacted with N-WASp and Dynamin-2 in an insulin-dependent manner. FRET confirmed the insulin-dependent, subcellular properties of these interactions. Insulin exposure stimulated specific interactions in plasma membrane and cytosolic compartments, followed by a steady-state response that underlies the coordination of proteins needed for GLUT4 traffic. Our findings reveal a physiological function for F-BAR proteins, supporting a previously unrecognized role for the F-BAR protein CIP4 in GLUT4 endocytosis, and show that interactions between CIP4 and Dynamin-2 and between CIP4 and NWASp are spatially coordinated to promote function. |
Databáze: | OpenAIRE |
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