Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10750615 | Biochemical and Biophysical Research Communications | 2015 | 7 Pages |
Abstract
R-Ras small GTPase enhances cell spreading and motility via RalBP1/RLIP76, an R-Ras effector that links GTP-R-Ras to activation of Arf6 and Rac1 GTPases. Here, we report that RLIP76 performs these functions by binding cytohesin-2/ARNO, an Arf GTPase guanine exchange factor, and connecting it to R-Ras at recycling endosomes. RLIP76 formed a complex with R-Ras and ARNO by binding ARNO via its N-terminus (residues 1-180) and R-Ras via residues 180-192. This complex was present in Rab11-positive recycling endosomes and the presence of ARNO in recycling endosomes required RLIP76, and was not supported by RLIP76(Î1-180) or RLIP76(Î180-192). Spreading and migration required RLIP76(1-180), and RLIP76(Î1-180) blocked ARNO recruitment to recycling endosomes, and spreading. Arf6 activation with an ArfGAP inhibitor overcame the spreading defects in RLIP76-depleted cells or cells expressing RLIP76(Î1-180). Similarly, RLIP76(Î1-180) or RLIP76(Î180-192) suppressed Arf6 activation. Together these results demonstrate that RLIP76 acts as a scaffold at recycling endosomes by binding activated R-Ras, recruiting ARNO to activate Arf6, thereby contributing to cell spreading and migration.
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Authors
Jeremy G.T. Wurtzel, Seunghyung Lee, Sharad S. Singhal, Sanjay Awasthi, Mark H. Ginsberg, Lawrence E. Goldfinger,