| pmid | 10406798 | ||||
|---|---|---|---|---|---|
| title | Got1p and Sft2p: membrane proteins involved in traffic to the Golgi complex. | ||||
| authors |
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| journal | EMBO J | ||||
| year | 1999 | ||||
| full_text_available | false | ||||
| full_text_extraction_method | html_abstract_only | ||||
| pmcid | PMC1171469 | ||||
| doi | 10.1093/emboj/18.14.3934 |
Authors: Conchon S, Cao X, Barlowe C, Pelham HR Journal: EMBO J (1999) DOI: 10.1093/emboj/18.14.3934 PMC: PMC1171469
- EMBO J. 1999 Jul 15;18(14):3934-46. doi: 10.1093/emboj/18.14.3934.
Got1p and Sft2p: membrane proteins involved in traffic to the Golgi complex.
Conchon S(1), Cao X, Barlowe C, Pelham HR.
Author information: (1)MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
Traffic through the yeast Golgi complex depends on a member of the syntaxin family of SNARE proteins, Sed5p, present in early Golgi cisternae. Sft2p is a non-essential tetra-spanning membrane protein, found mostly in the late Golgi, that can suppress some sed5 alleles. We screened for mutations that show synthetic lethality with sft2 and found one that affects a previously uncharacterized membrane protein, Got1p, as well as new alleles of sed5 and vps3. Got1p is an evolutionarily conserved non-essential protein with a membrane topology similar to that of Sft2p. Immunofluorescence and subcellular fractionation indicate that it is present in early Golgi cisternae. got1 mutants, but not sft2 mutants, show a defect in an in vitro assay for ER-Golgi transport at a step after vesicle tethering to Golgi membranes. In vivo, inactivation of both Got1p and Sft2p results in phenotypes ascribable to a defect in endosome-Golgi traffic, while their complete removal results in an ER-Golgi transport defect. Thus the presence of either Got1p or Sft2p is required for vesicle fusion with the Golgi complex in vivo. We suggest that Got1p normally facilitates Sed5p-dependent fusion events, while Sft2p performs a related function in the late Golgi.
DOI: 10.1093/emboj/18.14.3934 PMCID: PMC1171469 PMID: 10406798 [Indexed for MEDLINE]
Abstract
Traffic through the yeast Golgi complex depends on a member of the syntaxin family of SNARE proteins, Sed5p, present in early Golgi cisternae. Sft2p is a non-essential tetra-spanning membrane protein, found mostly in the late Golgi, that can suppress some sed5 alleles. We screened for mutations that show synthetic lethality with sft2 and found one that affects a previously uncharacterized membrane protein, Got1p, as well as new alleles of sed5 and vps3. Got1p is an evolutionarily conserved non-essential protein with a membrane topology similar to that of Sft2p. Immunofluorescence and subcellular fractionation indicate that it is present in early Golgi cisternae. got1 mutants, but not sft2 mutants, show a defect in an in vitro assay for ER-Golgi transport at a step after vesicle tethering to Golgi membranes. In vivo, inactivation of both Got1p and Sft2p results in phenotypes ascribable to a defect in endosome-Golgi traffic, while their complete removal results in an ER-Golgi transport defect. Thus the presence of either Got1p or Sft2p is required for vesicle fusion with the Golgi complex in vivo. We suggest that Got1p normally facilitates Sed5p-dependent fusion events, while Sft2p performs a related function in the late Golgi.