Abstract
Small GTPases and coiled-coil proteins of the golgin family help to tether COPI vesicles to Golgi membranes. At the cis-side of the Golgi, the Rab1 GTPase binds directly to each of three coiled-coil proteins: p115, GM130, and as now shown, Giantin. Rab1 binds to a coiled-coil region within the tail domain of p115 and this binding is inhibited by the C-terminal, acidic domain of p115. Furthermore, GM130 and Giantin bind to the acidic domain of p115 and stimulate p115 binding to Rab1, suggesting that p115 binding to Rab1 is regulated. Regulation of this interaction by proteins such as GM130 and Giantin may control the membrane recruitment of p115 by Rab1.
Highlights
Targeting of transport vesicles to the correct membrane compartment is a multilayered process consisting of tethering, docking, and fusion
It acts during ER to Golgi and intra-Golgi transport, as well as post-mitotic Golgi reassembly [15, 24]. p115 tethers COPI vesicles to Golgi membranes [25]
Our working model for the mechanism by which p115 tethers COPI vesicles to Golgi membranes has been that it forms a “bridge,” simultaneously binding and linking Giantin in COPI vesicle membranes to GM130 on the Golgi [25]
Summary
Targeting of transport vesicles to the correct membrane compartment is a multilayered process consisting of tethering, docking, and fusion. At the cis-side of the Golgi, the Rab1 GTPase binds directly to each of three coiled-coil proteins: p115, GM130, and as shown, Giantin. P115 localization to the Golgi region of cells is disrupted either by microinjection of a GM130 N-terminal peptide (N73), which inhibits p115 binding to GM130, or by overexpression of a truncated GM130 that lacks the p115binding domain [35].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
