The Saccharomyces cerevisiae MYO2 gene encodes an essential myosin for vectorial transport of vesicles

• Published in: The Journal of cell biology Vol. 113; no. 3; pp. 539 - 551
• Main Authors: Johnston, G.C. (Dalhousie University, Halifax, Nova Scotia, Canada), Prendergast, J.A, Singer, R.A
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.05.1991; The Rockefeller University Press
• Subjects: Actins; Actins - analysis; Amino Acid Sequence; Amino acids; Base Sequence; beta-Fructofuranosidase; Biological and medical sciences; Cell cycle; Cell growth; Cell physiology; Cells; Chitin - metabolism; CITOPLASMA; CLONACION; CLONAGE; CYTOPLASME; Cytoplasmic Granules - metabolism; Cytoskeleton - ultrastructure; Daughter cells; DIVISION CELLULAIRE; DIVISION CELULAR; ESTRUCTURA CELULAR; Fundamental and applied biological sciences. Psychology; GENE; GENES; Genes, Fungal; GLOBULINAS; GLOBULINE; Glycoside Hydrolases - metabolism; Mating Factor; Microscopy, Electron; Microtubules - ultrastructure; Molecular and cellular biology; Molecular Sequence Data; Mother cells; MUTACION; MUTATION; Myosins - genetics; Myosins - metabolism; NUCLEOTIDE; NUCLEOTIDOS; Peptides - metabolism; REPRODUCCION ASEXUAL; REPRODUCTION ASEXUEE; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - ultrastructure; SECRECION; SECRETION; STRUCTURE CELLULAIRE; Temperature; Yeasts; Fungi; Proteins; Gene; Nucleotide sequence; Enzyme; Biological transport; Myosin; Ascomycetes; Gene expression; Saccharomyces cerevisiae; Thallophyta
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.113.3.539

After the initiation of bud formation, cells of the yeast Saccharomyces cerevisiae direct new growth to the developing bud. We show here that this vectorial growth is facilitated by activity of the MYO2 gene. The wild-type MYO2 gene encodes an essential form of myosin composed of an NH2-terminal domain typical of the globular, actin-binding domain of other myosins. This NH2-terminal domain is linked by what appears to be a short alpha-helical domain to a novel COOH-terminal region. At the restrictive temperature the myo2-66 mutation does not impair DNA, RNA, or protein biosynthetic activity, but produces unbudded, enlarged cells. This phenotype suggests a defect in localization of cell growth. Measurements of cell size demonstrated that the continued development of initiated buds, as well as bud initiation itself, is inhibited. Bulk secretion continues in mutant cells, although secretory vesicles accumulate. The MYO2 myosin thus may function as the molecular motor to transport secretory vesicles along actin cables to the site of bud development