Role of the Arf6 GDP/GTP cycle and Arf6 GTPase-activating proteins in actin remodeling and intracellular transport.

We have analyzed both biochemically and functionally a series of Arf6 mutants, providing new insights into the molecular mode of action of the small G protein Arf6. First, by comparing a fast-cycling mutant (Arf6(T157N)) and a GTPase-deficient mutant (Arf6(Q67L)), we established the necessity for completion of the Arf6 GDP/GTP cycle ...
for recycling of major histocompatibility complex molecules to the plasma membrane. Second, we found that aluminum fluoride (AlF), known for inducing membrane protrusion in cells expressing exogenous wild-type Arf6, stabilized a functional wild-type Arf6.AlF(x) . GTPase-activating protein (GAP) complex in vitro and in vivo. We also found that the tandem mutation Q37E/S38I prevented the binding of two Arf GAPs, but not the effector ARHGAP10, and blocked the formation of membrane protrusion and actin reorganization. Together, our results with AlF(x) and Arf6(Q37E/S38I) demonstrate the critical role of the Arf6 GAPs as effectors for Arf6-regulated actin cytoskeleton remodeling. Finally, competition experiments conducted in vivo suggest the existence of a membrane receptor for GDP-bound Arf6.
Mesh Terms:
ADP-Ribosylation Factors, Actins, Aluminum Compounds, Animals, Biological Transport, Cell Line, Cricetinae, Cytoskeleton, Fluorides, GTPase-Activating Proteins, Guanosine Diphosphate, HeLa Cells, Humans, Mutation, Phospholipids, Protein Binding, Recombinant Proteins
J. Biol. Chem.
Date: May. 05, 2006
Download Curated Data For This Publication
207623
Switch View:
  • Interactions 5