From the Cover: Feature Article: Excess vacuolar SNAREs drive lysis and Rab bypass fusion Export

@article{citeulike:2210242, abstract = {Although concentrated soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) drive liposome fusion and lysis, the fusion of intracellular membranes also requires Rab GTPases, Rab effectors, SM proteins, and specific regulatory lipids and is accompanied by little or no lysis. To rationalize these findings, we generated yeast strains that overexpress all four vacuolar SNAREs (4SNARE++). Although vacuoles with physiological levels of Rab, Rab effector/SM complex, and SNAREs support rapid fusion without Rab- and SNARE-dependent lysis, vacuoles from 4SNARE++ strains show extensive lysis and a reduced need for the Rab Ypt7p or regulatory lipids for fusion. SNARE overexpression and the addition of pure homotypic fusion and vacuole protein sorting complex (HOPS), which bears the vacuolar SM protein, enables ypt7{Delta} vacuoles to fuse, allowing direct comparison of Rab-dependent and Rab-independent fusion. Because 3- to 40-fold more of each of the five components that form the SNARE/HOPS fusion complex are required for vacuoles from ypt7{Delta} strains to fuse at the same rate as vacuoles from wild-type strains, the apparent forward rate constant of 4SNARE/HOPS complex assembly is enhanced many thousand-fold by Ypt7p. Rabs function in normal membrane fusion by concentrating SNAREs, other proteins (e.g., SM), and key lipids at a fusion site and activating them for fusion without lysis. 10.1073/pnas.0704741104}, author = {Starai, Vincent J. and Jun, Youngsoo and Wickner, William}, citeulike-article-id = {2210242}, citeulike-linkout-0 = {http://dx.doi.org/10.1073/pnas.0704741104}, citeulike-linkout-1 = {http://www.pnas.org/cgi/content/abstract/104/34/13551}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/17699614}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=17699614}, day = {21}, doi = {10.1073/pnas.0704741104}, journal = {Proceedings of the National Academy of Sciences}, month = {August}, number = {34}, pages = {13551--13558}, posted-at = {2008-01-09 08:27:05}, priority = {2}, title = {From the Cover: Feature Article: Excess vacuolar SNAREs drive lysis and Rab bypass fusion}, url = {http://dx.doi.org/10.1073/pnas.0704741104}, volume = {104}, year = {2007} }

TY - JOUR ID - citeulike:2210242 L3 - citeulike-article-id:2210242 N2 - Although concentrated soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) drive liposome fusion and lysis, the fusion of intracellular membranes also requires Rab GTPases, Rab effectors, SM proteins, and specific regulatory lipids and is accompanied by little or no lysis. To rationalize these findings, we generated yeast strains that overexpress all four vacuolar SNAREs (4SNARE++). Although vacuoles with physiological levels of Rab, Rab effector/SM complex, and SNAREs support rapid fusion without Rab- and SNARE-dependent lysis, vacuoles from 4SNARE++ strains show extensive lysis and a reduced need for the Rab Ypt7p or regulatory lipids for fusion. SNARE overexpression and the addition of pure homotypic fusion and vacuole protein sorting complex (HOPS), which bears the vacuolar SM protein, enables ypt7{Delta} vacuoles to fuse, allowing direct comparison of Rab-dependent and Rab-independent fusion. Because 3- to 40-fold more of each of the five components that form the SNARE/HOPS fusion complex are required for vacuoles from ypt7{Delta} strains to fuse at the same rate as vacuoles from wild-type strains, the apparent forward rate constant of 4SNARE/HOPS complex assembly is enhanced many thousand-fold by Ypt7p. Rabs function in normal membrane fusion by concentrating SNAREs, other proteins (e.g., SM), and key lipids at a fusion site and activating them for fusion without lysis. 10.1073/pnas.0704741104 IS - 34 JF - Proceedings of the National Academy of Sciences EP - 13558 TI - From the Cover: Feature Article: Excess vacuolar SNAREs drive lysis and Rab bypass fusion VL - 104 SP - 13551 AU - Starai, Vincent AU - Jun, Youngsoo AU - Wickner, William PY - 2007/08/21/ UR - http://dx.doi.org/10.1073/pnas.0704741104 ER -