title: The Saccharomyces cerevisiae early secretion mutant tip20 is synthetic lethal with mutants in yeast coatomer and the SNARE proteins Sec22p and Ufe1p.
abstract: Tip20p is an 80 kDa cytoplasmic protein bound to the cytoplasmic surface of the endoplasmic reticulum (ER) by interaction with the type II integral membrane protein Sec20p. Both proteins are required for vesicular transport between the ER and Golgi complex. Recently, sec20-1 was found to be defective in retrograde transport. A collection of temperature-sensitive tip20 mutants are shown to be lethal in combination with ufe1-1, a target SNARE of the ER and ret2-1, yeast delta-COP. A subset of tip20 mutants was found to be lethal in combination with sec20-1, sec21-1, sec22-3 and sec27-1. Since all pairwise combinations of a tip20 mutant, sec20-1, and ufe1-1 are lethal, Tip20p and Sec20p might be part of the docking complex for Golgi-derived retrograde transport vesicles. Since carboxy-terminal tip20 truncations are lethal in combination with mutants in three coatomer subunits, Tip20p might be involved in binding or uncoating of COPI coated retrograde transport vesicles.
authors.affiliation: Sanger Centre, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.
authors.forename: G
authors.initials: G
authors.lastname: Frigerio
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism; D020756:Coatomer Protein; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D006023:Glycoproteins; D006056:Golgi Apparatus / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D015388:Organelles / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050683:R-SNARE Proteins; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D014170:Transformation, Genetic; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; D020756:Coatomer Protein; D005656:Fungal Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050683:R-SNARE Proteins; D011956:Receptors, Cell Surface; C073173:SEC20 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C106909:Sec22 protein, S cerevisiae; C489479:TIP20 protein, S cerevisiae; C103868:UFE1 protein, S cerevisiae; D033921:Vesicular Transport Proteins