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The carboxy-terminal region of the TBC1D4 (AS160) RabGAP mediates protein homodimerization
- Woo, Ju Rang, Kim, Soon-Jong, Kim, Keon Young, Jang, Hyonchol, Shoelson, Steven E., Park, SangYoun
- International journal of biological macromolecules 2017 v.103 pp. 965-971
- GTPase-activating proteins, catalytic activity, dimerization, glucose, glucose transporters, insulin, phosphorylation, plasma membrane, prediction, thermal stability
- TBC1D4 (also known as AS160) is a Rab·GTPase-activating protein (RabGAP) which functions in insulin signaling. TBC1D4 is critical for translocation of glucose transporter 4 (GLUT4), from an inactive, intracellular, vesicle-bound site to the plasma membrane, where it promotes glucose entry into cells. The TBC1D4 protein is structurally subdivided into two N-terminal phosphotyrosine-binding (PTB) domains, a C-terminal catalytic RabGAP domain, and a disordered segment in between containing potential Akt phosphorylation sites. Structural predictions further suggest that a region C-terminal to the RabGAP domain adopts a coiled-coil motif. We show that C-terminal region (CTR) region is largely α-helical and mediates TBC1D4 RabGAP dimerization. RabGAP catalytic activity and thermal stability appear to be independent of CTR-mediated dimerization.