Mammalian Sly1 regulates syntaxin 5 function in endoplasmic reticulum to Golgi transport.
Members of the syntaxin gene family are components of protein complexes which regulate vesicle docking and/or fusion during transport of cargo through the secretory pathway of eukaryotic cells. We have previously demonstrated that syntaxin 5 is specifically required for endoplasmic reticulum to Golgi transport (Dascher, C., Matteson, J., and Balch, W. E.(1994) J. Biol. Chem. 269, 29363-29366). To extend these observations we have now cloned a protein from rat liver membranes which forms a native complex with syntaxin 5. We demonstrate that this protein is the mammalian homologue to yeast Sly1p, previously identified as a protein which genetically and biochemically interacts with the small GTPase Ypt1p and Sed5p, proteins involved in docking/fusion in the early secretory pathway of yeast. Using transient expression we find that overexpression of rat liver Sly1 (rSly1) can neutralize the dominant negative effects of excess syntaxin 5 on endoplasmic reticulum to Golgi transport. These results suggest that rSly1 functions to positively regulate syntaxin 5 function.
Dascher
C
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Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92130, USA.
Balch
W E
WE
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers; D018076:DNA, Complementary; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D017874:Immediate-Early Proteins; D008099:Liver / Q000378:metabolism*; D008322:Mammals; D008565:Membrane Proteins / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D051938:Munc18 Proteins; D009206:Myocardium / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D050765:Qa-SNARE Proteins; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D005656:Fungal Proteins; D017874:Immediate-Early Proteins; D008565:Membrane Proteins; D051938:Munc18 Proteins; D050765:Qa-SNARE Proteins; C072520:SLY1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C106568:Scfd1 protein, rat