Sec3p is a spatial landmark for polarized secretion in budding yeast.
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.
Finger
F P
FP
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
Hughes
T E
TE
Novick
P
P
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
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