imp2, a new component of the actin ring in the fission yeast Schizosaccharomyces pombe.
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.
Demeter
J
J
Verna and Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030, USA.
Sazer
S
S
D000199:Actins / Q000378:metabolism*; D002451:Cell Compartmentation / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002874:Chromosome Mapping; D003598:Cytoskeletal Proteins; D010450:Endopeptidases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D044767:Ubiquitin-Protein Ligases
D000199:Actins; C082279:CDC15 protein; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; C513272:Fbxw7 protein, mouse; D005656:Fungal Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C513274:cdc4 protein, S pombe; D044767:Ubiquitin-Protein Ligases; D010450:Endopeptidases; C067167:IMP1 protein, S cerevisiae; D019204:GTP-Binding Proteins