title: Sec3p is a spatial landmark for polarized secretion in budding yeast.
abstract: Exocytosis in yeast occurs at plasma membrane subdomains whose locations vary with the cell cycle, but the primary protein determinants of these sites are unknown. A functional fusion of Sec3 protein with green fluorescent protein (Sec3-GFP) localizes to the site of polarized exocytosis for each cell-cycle stage, where it colocalizes with Sec4p and Sec8p. Sec3-GFP localization is independent of secretory pathway function, of the actin and septin cytoskeletons, and of the polarity establishment proteins. We propose that Sec3p is a spatial landmark defining sites of exocytosis. Polarized secretion would result from the coupling of actin-dependent vesicle targeting with Sec3p-dependent establishment of the vesicle fusion site.
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
authors.forename: F P
authors.initials: FP
authors.lastname: Finger
authors.forename: T E
authors.initials: TE
authors.lastname: Hughes
authors.forename: P
authors.initials: P
authors.lastname: Novick
mesh_terms: D000199:Actins / Q000032:analysis / Q000378:metabolism; D002352:Carrier Proteins; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics; D016764:Cell Polarity / Q000502:physiology*; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000737:chemistry / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology*; D005656:Fungal Proteins / Q000032:analysis / Q000378:metabolism*; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins / Q000032:analysis; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents; D007425:Intracellular Membranes / Q000502:physiology; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009154:Mutation; D051304:Profilins; D011506:Proteins / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors / Q000032:analysis; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins
chemical_list: D000199:Actins; C099504:CDC12 protein, S cerevisiae; C086662:CDC3 protein, S cerevisiae; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D008565:Membrane Proteins; D051304:Profilins; D011506:Proteins; C103130:SEC3 protein, S cerevisiae; C489603:SEC8 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D033921:Vesicular Transport Proteins; C061178:cdc10 protein, S pombe; D049452:Green Fluorescent Proteins; C512892:CDC10 protein, S cerevisiae; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C064320:SEC4 protein, S cerevisiae; D020691:rab GTP-Binding Proteins