Without ARFGAP1 or GTP, vesicles cannot load their cargo.

The effect of ARF1 GTPase-activating protein (ARFGAP1) on vesicle formation is making a turn-around. Contrary to previous theories, GAP does not antagonize COPI coat recruitment. As shown by Yang et al. on page 69, its newly discovered function reveals conservation among GAPs in anterograde and retrograde transport pathways.

COPI vesicle formation is initiated by the ADP-Ribosylation Factor (ARF) family of small GTPases, which recruits COPI coatomer subunits to Golgi membranes. ARFGAP1 inactivates ARF1 by stimulating GTP hydrolysis. Because COPI vesicles formed in vitro using nonhydrolyzable GTP (GTPγS) or GTP-bound ARF1 do not uncoat, it has been inferred that ARFGAP1 stimulates uncoating, and thus inhibits vesicle formation. But the new experiments, using hydrolyzable GTP, provide a clearer view of the ARFGAP1 function.

Yang et al. found that ARFGAP1 had the opposite effect of what was previously...

The Rockefeller University Press
2002
The Rockefeller University Press
2002
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