title: The SNARE Ykt6 mediates protein palmitoylation during an early stage of homotypic vacuole fusion.
abstract: The NSF homolog Sec18 initiates fusion of yeast vacuoles by disassembling cis-SNARE complexes during priming. Sec18 is also required for palmitoylation of the fusion factor Vac8, although the acylation machinery has not been identified. Here we show that the SNARE Ykt6 mediates Vac8 palmitoylation and acts during a novel subreaction of vacuole fusion. This subreaction is controlled by a Sec17-independent function of Sec18. Our data indicate that Ykt6 presents Pal-CoA via its N-terminal longin domain to Vac8, while transfer to Vac8's SH4 domain occurs spontaneously and not enzymatically. The conservation of Ykt6 and its localization to several organelles suggest that its acyltransferase activity may also be required in other intracellular fusion events.
authors.affiliation: Biochemie-Zentrum Heidelberg (BZH), University of Heidelberg, Heidelberg, Germany.
authors.forename: Lars E P
authors.initials: LE
authors.lastname: Dietrich
authors.forename: Rolf
authors.initials: R
authors.lastname: Gurezka
authors.forename: Michael
authors.initials: M
authors.lastname: Veit
authors.forename: Christian
authors.initials: C
authors.lastname: Ungermann
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D003065:Coenzyme A / Q000378:metabolism; D017124:Conserved Sequence; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010168:Palmitates / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D050683:R-SNARE Proteins; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014617:Vacuoles; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D010168:Palmitates; D050683:R-SNARE Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; C107127:YKT6 protein, S cerevisiae; D000255:Adenosine Triphosphate; D000123:Acetyltransferases; D000251:Adenosine Triphosphatases; C064404:SEC18 protein, S cerevisiae; D003065:Coenzyme A