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The binding of Vps33p to the N‐terminal domain of the yeast vacuolar syntaxin Vam3p is not required for yeast vacuole fusion
Author(s) -
Lee Miriam,
Ko Youngjun,
Cho Sunglim,
Jun Youngsoo
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.988.1
Subject(s) - vacuole , syntaxin , transmembrane domain , yeast , transmembrane protein , lipid bilayer fusion , microbiology and biotechnology , biology , cleavage (geology) , fusion protein , c terminus , biochemistry , membrane protein , membrane , recombinant dna , cytoplasm , amino acid , gene , paleontology , receptor , fracture (geology)
Vam3p, the syntaxin‐like yeast vacuolar Q‐SNARE, is essential for homotypic yeast vacuole fusion. Similar to other syntaxin family proteins, Vam3p possesses a three‐helical N‐terminal domain, a SNARE domain, and a C‐terminal transmembrane domain. It is generally accepted that the SNARE and transmembrane domains are required for Vam3p to mediate membrane fusion, but the requirement of the N‐terminal domain for the Vam3p function remains unclear. To examine whether the N‐terminal domain of Vam3p is required for vacuole fusion, we constructed two Vam3p constructs: one that lacks its entire N‐terminal domain and the other that contains a tobacco etch virus (TEV) protease‐cleavage site (TCS) between the N‐terminal and the transmembrane domains. The N‐terminal domain deletion either genetically or through TEV protease cleavage only moderately reduced vacuole fusion, indicating that the N‐terminal domain of Vam3p plays a marginal role in vacuole fusion. Despite this dispensability for fusion, the N‐terminal domain is strictly required for the binding of Vps33p, the Sec1/Munc18 family protein essential for vacuole fusion, to Vam3p. Thus, these results suggest that Vps33p binding to Vam3p is not required for yeast vacuole fusion.