imp2, a new component of the actin ring in the fission yeast Schizosaccharomyces pombe

• Published in: The Journal of cell biology Vol. 143; no. 2; pp. 415 - 427
• Main Authors: Demeter, J. (Baylor College of Medicine, Houston, TX.), Sazer, S
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 19.10.1998; The Rockefeller University Press
• Subjects: ACTIN; ACTIN MEDIAL RING; ACTINA; ACTINE; Actins; Actins - metabolism; ADN; AMINO ACID SEQUENCES; BINDING PROTEINS; BIOCHEMISTRY; BIOCHIMIE; BIOQUIMICA; Cell Compartmentation - physiology; Cell cycle; Cell Cycle - physiology; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; CELL DIVISION; CELL SEPTATION; CELL SEPTUM; CELL STRUCTURE; Cell walls; Cells; Cellular biology; CHEMICAL COMPOSITION; Chromosome Mapping; CITOLOGIA; COMPLEMENTARY DNA; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CYTOCHEMISTRY; Cytokinesis; CYTOLOGIE; CYTOLOGY; Cytoskeletal Proteins; CYTOSKELETON; Daughter cells; DIVISION CELLULAIRE; DIVISION CELULAR; DNA; Endopeptidases - genetics; Endopeptidases - isolation & purification; Endopeptidases - metabolism; ESPORAS; ESTRUCTURA CELULAR; F-Box Proteins; F-Box-WD Repeat-Containing Protein 7; Fungal Proteins - metabolism; GENBANK/Z69379; GENE; Gene Deletion; Gene Expression Regulation, Fungal; GENES; GERMINACION; GERMINATION; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; IMP2 GENE; Mitochondrial Proteins; MOLECULAR SEQUENCE DATA; Mutagenesis - physiology; NUCLEOTIDE SEQUENCE; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; Regular; Saccharomyces cerevisiae Proteins; Schizosaccharomyces; Schizosaccharomyces - cytology; Schizosaccharomyces - enzymology; SCHIZOSACCHAROMYCES POMBE; Schizosaccharomyces pombe Proteins; SECUENCIA NUCLEOTIDICA; Septum; Sequence Homology, Amino Acid; SEQUENCE NUCLEOTIDIQUE; SPORE; SPORES; STRUCTURAL GENES; STRUCTURE CELLULAIRE; Ubiquitin-Protein Ligases; Yeast; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.143.2.415

Cytokinesis is the part of the cell cycle in which the cell is cleaved to form two daughter cells. The unicellular yeast, Schizosaccharomyces pombe is an excellent model organism in which to study cell division, since it shows the general features of eukaryotic cell division and is amenable to genetic analysis. In this manuscript we describe the isolation and characterization of a new protein, imp2, which is required for normal septation in fission yeast. imp2, which colocalizes with the medial ring during septation, is structurally similar to a group of proteins including the S. pombe cdc15 and the mouse PSTPIP that are localized to, and thought to be involved in actin ring organization. Cells in which the imp2 gene is deleted or overexpressed have septation and cell separation defects. An analysis of the actin cytoskeleton shows the lack of a medial ring in septating cells that overexpress imp2, and the appearance of abnormal medial ring structures in septated cells that lack imp2. These observations suggest that imp2 destabilizes the medial ring during septation. imp2 also shows genetic interactions with several, previously characterized septation genes, strengthening the conclusion that it plays a role in normal fission yeast septation.