title: The budding yeast Pichia pastoris has a novel Sec23p homolog.
abstract: In Pichia pastoris, coat protein complex II (COPII) vesicles form at discrete transitional ER (tER) sites. Analyzing COPII coat proteins in this yeast will help to reveal the mechanisms of tER organization. Here, we show that like Saccharomyces cerevisiae, P. pastoris contains essential SEC23 and SEC24 genes, as well as the non-essential SEC24 homolog LST1. In addition, P. pastoris contains a novel non-essential SEC23 homolog that we have designated SHL23. The products of all four genes are concentrated at tER sites. Deletion of SHL23 does not disrupt tER morphology. As judged by two-hybrid analysis, Sec23p associates with both Sec24p and Lst1p, whereas Shl23p associates selectively with Lst1p. These results suggest that P. pastoris COPII vesicles contain an Shl23p/Lst1p complex that is absent in S. cerevisiae.
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, IL 60637, USA.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Esaki
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Glick
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D001692:Biological Transport / Q000235:genetics; D022181:COP-Coated Vesicles / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D020690:GTPase-Activating Proteins; D005800:Genes, Fungal / Q000235:genetics*; D027381:Liver-Specific Organic Anion Transporter 1 / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010843:Pichia / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D027381:Liver-Specific Organic Anion Transporter 1; D008565:Membrane Proteins; C079037:SEC23 protein, S cerevisiae; C118289:SEC24 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins