Mutations of the SM protein Sly1 resulting in bypass of GTPase requirement in vesicular transport are confined to a short helical region.
Ypt/Rab GTPases and Sec1/Munc18 (SM) proteins are key components of the membrane fusion machinery. Here, we describe new mutants of the yeast SM protein Sly1 that specifically bypass the need for GTPases Ypt1 and Ypt6 in vesicular transport. All sequence alterations are confined to a short alpha-helix (alpha-20), which is conserved in fungal Sly1 proteins and, when deleted, results in GTPase suppression. Whereas Sly1p of the evolutionarily distant fission yeast Schizosaccharomyces pombe can functionally replace Sly1p in Sacchromyces cerevisiae, mammalian homologues cannot. This indicates that alpha-20 in fungal Sly1p plays an important role in mediating Ypt/Rab-regulated Sly1p function in membrane fusion.
Li
Yujie
Y
Department of Molecular Genetics, Max Planck Institute for Biophysical Chemistry, 37070, Göttingen, Germany.
Schmitt
Hans Dieter
HD
Gallwitz
Dieter
D
Peng
Ren-Wang
RW
D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D017874:Immediate-Early Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051938:Munc18 Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D011487:Protein Conformation; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D022161:Transport Vesicles / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
D033942:Adaptor Proteins, Vesicular Transport; D017874:Immediate-Early Proteins; D051938:Munc18 Proteins; C527528:SCFD1 protein, human; C072520:SLY1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C106568:Scfd1 protein, rat; D029702:Schizosaccharomyces pombe Proteins; C527529:Sly1 protein, S pombe; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins