Sec35p, a novel peripheral membrane protein, is required for ER to Golgi vesicle docking.
SEC35 was identified in a novel screen for temperature-sensitive mutants in the secretory pathway of the yeast Saccharomyces cerevisiae (. Genetics. 142:393-406). At the restrictive temperature, the sec35-1 strain exhibits a transport block between the ER and the Golgi apparatus and accumulates numerous vesicles. SEC35 encodes a novel cytosolic protein of 32 kD, peripherally associated with membranes. The temperature-sensitive phenotype of sec35-1 is efficiently suppressed by YPT1, which encodes the rab-like GTPase required early in the secretory pathway, or by SLY1-20, which encodes a dominant form of the ER to Golgi target -SNARE-associated protein Sly1p. Weaker suppression is evident upon overexpression of genes encoding the vesicle-SNAREs SEC22, BET1, or YKT6. The cold-sensitive lethality that results from deleting SEC35 is suppressed by YPT1 or SLY1-20. These genetic relationships suggest that Sec35p acts upstream of, or in conjunction with, Ypt1p and Sly1p as was previously found for Uso1p. Using a cell-free assay that measures distinct steps in vesicle transport from the ER to the Golgi, we find Sec35p is required for a vesicle docking stage catalyzed by Uso1p. These genetic and biochemical results suggest Sec35p acts with Uso1p to dock ER-derived vesicles to the Golgi complex.
VanRheenen
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SM
Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
Cao
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Lupashin
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Barlowe
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Waters
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D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018699:Coated Vesicles / Q000378:metabolism; D004271:DNA, Fungal; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D006056:Golgi Apparatus / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D051938:Munc18 Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins
C112749:COG2 protein, S cerevisiae; D002352:Carrier Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D051938:Munc18 Proteins; C072520:SLY1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C086888:USO1 protein, S cerevisiae; D033921:Vesicular Transport Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C060755:YPT1 protein, S cerevisiae; D020691:rab GTP-Binding Proteins