Moyer B D, Allan B B, Balch W E
Department of Cell and Molecular Biology, The Institute for Childhood and Neglected Diseases, The Scripps Research Institute, 10550 N. Torrey Pines Road, San Diego, California 92037, USA.
Traffic. 2001 Apr;2(4):268-76. doi: 10.1034/j.1600-0854.2001.1o007.x.
Members of the Rab family of small molecular weight GTPases regulate the fusion of transport intermediates to target membranes along the biosynthetic and endocytic pathways. We recently demonstrated that Rab1 recruitment of the tethering factor p115 into a cis-SNARE complex programs coat protein II vesicles budding from the endoplasmic reticulum (donor compartment) for fusion with the Golgi apparatus (acceptor compartment) (Allan BB, Moyer BD, Balch WE. Science 2000; 289: 444-448). However, the molecular mechanism(s) of Rab regulation of Golgi acceptor compartment function in endoplasmic reticulum to Golgi transport are unknown. Here, we demonstrate that the cis-Golgi tethering protein GM130, complexed with GRASP65 and other proteins, forms a novel Rab1 effector complex that interacts with activated Rab1-GTP in a p115-independent manner and is required for coat protein II vesicle targeting/fusion with the cis-Golgi. We propose a 'homing hypothesis' in which the same Rab interacts with distinct tethering factors at donor and acceptor membranes to program heterotypic membrane fusion events between transport intermediates and their target compartments.
小分子重量GTP酶的Rab家族成员调节沿着生物合成和内吞途径的运输中间体与靶膜的融合。我们最近证明，Rab1将拴系因子p115招募到顺式SNARE复合体中，为从内质网（供体区室）出芽的II型被膜小泡与高尔基体（受体区室）的融合编程（Allan BB，Moyer BD，Balch WE。《科学》2000年；289：444 - 448）。然而，Rab在内质网到高尔基体运输中对高尔基体受体区室功能的调节分子机制尚不清楚。在这里，我们证明，与GRASP65和其他蛋白质复合的顺式高尔基体拴系蛋白GM130形成一种新型的Rab1效应器复合体，它以不依赖p115的方式与活化的Rab1 - GTP相互作用，并且是II型被膜小泡靶向/与顺式高尔基体融合所必需的。我们提出一个“归巢假说”，即同一个Rab在供体和受体膜上与不同的拴系因子相互作用，为运输中间体与其靶区室之间的异型膜融合事件编程。
