title: Rpg1p, the subunit of the Saccharomyces cerevisiae eIF3 core complex, is a microtubule-interacting protein.
abstract: The essential gene RPG1/TIF32 of Saccharomyces cerevisiae encodes the 110-kDa subunit of the translation initiation factor 3 (eIF3) core complex. In this study, the Rpg1p-specific monoclonal antibody PK1/1 was used to analyse the cellular distribution of Rpg1p by epifluorescence and confocal laser scanning microscopy (CLSM). In budded cells, a portion of Rpg1p was obviously co-localised with microtubules. In addition, CLSM revealed an accumulation of Rpg1p in a patch at the very end of cytoplasmic microtubules reaching the bud tip. A punctate fluorescence pattern was typical for separated unbudded cells. Distribution of Rpg1p was confirmed using a strain expressing exclusively a hemaglutinin-tagged version of Rpg1p. In nocodazole-treated cells, the pattern of the PK1/1 staining was disturbed. No staining was observed in Rpg1p-depleted cells. In vitro experiments revealed that Rpg1p was specifically co-immunoprecipitated with alpha-tubulin from the yeast cell free extract and this observation was further supported by showing that Rpg1p co-sedimented with hog brain microtubules. We conclude that Rpg1p is a microtubule-interacting protein that indicates an interesting connection between the translation initiation machinery and cytoskeleton in yeast Saccharomyces cerevisiae.
authors.affiliation: Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Hasek
authors.forename: P
authors.initials: P
authors.lastname: Kovarik
authors.forename: L
authors.initials: L
authors.lastname: Valásek
authors.forename: K
authors.initials: K
authors.lastname: Malínská
authors.forename: J
authors.initials: J
authors.lastname: Schneider
authors.forename: S D
authors.initials: SD
authors.lastname: Kohlwein
authors.forename: H
authors.initials: H
authors.lastname: Ruis
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D039621:Eukaryotic Initiation Factor-3; D005455:Fluorescent Antibody Technique; D008870:Microtubules / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism; D039665:Prokaryotic Initiation Factor-3; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D018797:Cell Cycle Proteins; D039621:Eukaryotic Initiation Factor-3; D010448:Peptide Initiation Factors; D039665:Prokaryotic Initiation Factor-3; C111889:RPG1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins