title: Yeast proteins related to the p40/laminin receptor precursor are essential components of the 40 S ribosomal subunit.
abstract: We report here the isolation of two genes from the yeast, Saccharomyces cerevisiae, that encode proteins closely related to mammalian p40/laminin receptor precursors (LRPs). The yeast genes, designated YST1 and YST2, encode proteins with over 95% amino acid sequence identity with one another and over 60% identity with the human p40/laminin receptor precursor. The Yst/p40/37-LRP proteins are also more distantly related to the S2 family of ribosomal proteins. Analysis of the distribution of Yst1 tagged with the c-myc epitope revealed that the Yst proteins are components of the 40 S ribosomal subunit. Disruption of either YST1 or YST2 causes a significant reduction in growth rate, while disruption of both genes is lethal. Compared to wild type, polysome profiles in strains lacking either YST1 or YST2 show a pronounced shift from larger to smaller polysomes. This shift is accompanied by a substantial increase in free 60 S subunits and reduced levels of 40 S subunits. We conclude that the Yst proteins are required for translation and contribute to the assembly and/or stability of the 40 S ribosomal subunit.
authors.affiliation: Department of Biochemistry, University of Louisville, Kentucky 40292, USA.
authors.forename: M
authors.initials: M
authors.lastname: Demianova
authors.forename: T G
authors.initials: TG
authors.lastname: Formosa
authors.forename: S R
authors.initials: SR
authors.lastname: Ellis
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000737:chemistry; D015870:Gene Expression; D005800:Genes, Fungal; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D011132:Polyribosomes / Q000378:metabolism / Q000648:ultrastructure; D011498:Protein Precursors / Q000737:chemistry*; D012333:RNA, Messenger / Q000378:metabolism; D017474:Receptors, Laminin; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012269:Ribosomal Proteins; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D016324:Sequence Tagged Sites
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011498:Protein Precursors; D012333:RNA, Messenger; C099412:RPS0A protein, S cerevisiae; C099413:RPS0B protein, S cerevisiae; D017474:Receptors, Laminin; D011994:Recombinant Proteins; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins