Involvement of LMA1 and GATE-16 family members in intracellular membrane dynamics.
Intracellular membrane fusion is conserved from yeast to man as well as among different intracellular trafficking pathways. This process can be generally divided into several well-defined biochemical reactions. First, an early recognition (or tethering) takes place between donor and acceptor membranes, mediated by ypt/rab GTPases and complexes of tethering factors. Subsequently, a closer association between the two membranes is achieved by a docking process, which involves tight association between membrane proteins termed SNAREs. The formation of such a trans-SNARE complex leads to the final membrane fusion, resulting in an accumulation of cis-SNARE complexes on the acceptor membrane. Thus, multiple rounds of transport and delivery of the donor SNARE back to its original membrane require dissociation of the SNARE complexes. SNARE dissociation, termed priming, is mediated by the AAA ATPase, N-ethylmaleimide-sensitive factor (NSF) and its partner, soluble NSF attachment protein (SNAP), in a reaction that requires ATP hydrolysis. In the present review we focus on LMA1 and GATE-16, two low-molecular-weight proteins, which assist in priming SNARE molecules in the vacuole in yeast and the Golgi complex in mammals, respectively. LMA1 and GATE-16 are suggested to keep the dissociated cis-SNAREs apart from each other, allowing multiple fusion processes to take place. GATE-16 belongs to a novel family of ubiquitin-like proteins conserved from yeast to man. We discuss here the involvement of this family in multiple intracellular trafficking pathways.
Elazar
Zvulun
Z
Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel. bmzevi@wicc.weizman.ac.il
Scherz-Shouval
Ruth
R
Shorer
Hagai
H
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D000071190:Autophagy-Related Protein 8 Family; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007425:Intracellular Membranes / Q000502:physiology*; D008561:Membrane Fusion / Q000502:physiology; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D033921:Vesicular Transport Proteins; D015003:Yeasts / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; D000071190:Autophagy-Related Protein 8 Family; D002352:Carrier Proteins; C498698:GABARAPL2 protein, human; D008840:Microfilament Proteins; C068476:PBI2 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins