The mechanisms of protein secretion and assembly into biological membranes will be studied by a combined biochemical and genetic approach. Trigger factor, a protein which catalyzes the folding of pre-secretory proteins into an assembly-competent form, will be purified and its mode of action characterized. It`s gene will be isolated and used to establish the physiological role of this protein. Translocation competent membrane vesicles will be solubilized with detergents and those proteins which are needed for secretion and membrane assembly will be isolated. Particular emphasis will be placed on illuminating the basis for two energy requirements for membrane assembly, ATP and the membrane electrochemical potential. In addition, we will characterize translocation poison sequences and hydrophobic helpers, two newly discovered elements within proteins which govern their membrane assembly.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Method to Extend Research in Time (MERIT) Award (R37)
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Microbial Physiology and Genetics Subcommittee 2 (MBC)
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University of California Los Angeles
Schools of Medicine
Los Angeles
United States
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Orr, Amy; Wickner, William; Rusin, Scott F et al. (2015) Yeast vacuolar HOPS, regulated by its kinase, exploits affinities for acidic lipids and Rab:GTP for membrane binding and to catalyze tethering and fusion. Mol Biol Cell 26:305-15
Baker, Richard W; Jeffrey, Philip D; Zick, Michael et al. (2015) A direct role for the Sec1/Munc18-family protein Vps33 as a template for SNARE assembly. Science 349:1111-4
Xu, Hao; Wickner, William T (2012) N-terminal domain of vacuolar SNARE Vam7p promotes trans-SNARE complex assembly. Proc Natl Acad Sci U S A 109:17936-41
Xu, Hao; Zick, Michael; Wickner, William T et al. (2011) A lipid-anchored SNARE supports membrane fusion. Proc Natl Acad Sci U S A 108:17325-30
Zucchi, Paola C; Zick, Michael (2011) Membrane fusion catalyzed by a Rab, SNAREs, and SNARE chaperones is accompanied by enhanced permeability to small molecules and by lysis. Mol Biol Cell 22:4635-46
Xu, Hao; Wickner, William (2010) Phosphoinositides function asymmetrically for membrane fusion, promoting tethering and 3Q-SNARE subcomplex assembly. J Biol Chem 285:39359-65
Xu, Hao; Jun, Youngsoo; Thompson, James et al. (2010) HOPS prevents the disassembly of trans-SNARE complexes by Sec17p/Sec18p during membrane fusion. EMBO J 29:1948-60
Mima, Joji; Wickner, William (2009) Phosphoinositides and SNARE chaperones synergistically assemble and remodel SNARE complexes for membrane fusion. Proc Natl Acad Sci U S A 106:16191-6
Stroupe, Christopher; Hickey, Christopher M; Mima, Joji et al. (2009) Minimal membrane docking requirements revealed by reconstitution of Rab GTPase-dependent membrane fusion from purified components. Proc Natl Acad Sci U S A 106:17626-33
Mima, Joji; Hickey, Christopher M; Xu, Hao et al. (2008) Reconstituted membrane fusion requires regulatory lipids, SNAREs and synergistic SNARE chaperones. EMBO J 27:2031-42

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