Schizosaccharomyces pombe cdc4+ gene encodes a novel EF-hand protein essential for cytokinesis

• Published in: The Journal of cell biology 1995-08, Vol.130 (3), p.651-660
• Main Authors: McCollum, Dannel, Balasubramanian, Mohan K., Pelcher, Lawrence E., Hemmingsen, Sean M., Gould, Kathleen L.
• Format: Article
• Language: English
• Subjects: Actins; Alleles; Amino Acid Sequence; Antibodies; Base Sequence; Cell Compartmentation; Cell cycle; Cell Cycle Proteins - genetics; Cell Cycle Proteins - physiology; cell division; Cell Division - genetics; Cell nucleus; Cells; chemical composition; Cloning, Molecular; composicion quimica; composition chimique; Cytokinesis; Cytoskeletal Proteins; division cellulaire; division celular; Escherichia coli - genetics; F-Box Proteins; fenotipos; Fluorescent Antibody Technique; Fungal Proteins - genetics; Fungal Proteins - physiology; gene; genes; Genes, Fungal - genetics; globulinas; globuline; globulins; immunofluorescence; immunologie; immunology; inmunofluorescencia; inmunologia; Molecular Sequence Data; mutant; mutantes; mutants; Mutation; nucleotide sequence; Nurses; peptide; peptides; peptidos; Phenotype; phenotypes; Precipitin Tests; Protein Binding; Recombinant Proteins - biosynthesis; Schizosaccharomyces; Schizosaccharomyces - genetics; schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins; secuencia nucleica; Sequence Analysis, DNA; Sequence Homology, Amino Acid; sequence nucleique; Ubiquitin-Protein Ligases; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.130.3.651

Schizosaccharomyces pombe cells divide by medial fission. One class of cell division mutants (cdc), the late septation mutants, defines four genes: cdc3, cdc4, cdc8, and cdc12 (Nurse, P., P. Thuriaux, and K. Nasmyth. 1976. Mol. and Gen. Genet. 146:167-178). We have cloned and characterized the cdc4 gene and show that the predicted gene product, Cdc4p, is a 141-amino acid polypeptide that is similar in sequence to EF-hand proteins including myosin light chains, calmodulin, and troponin C. Two temperature-sensitive lethal alleles, cdc4-8 and cdc4-31, accumulate multiple nuclei and multiple improper F-actin rings and septa but fail to complete cytokinesis. Deletion of cdc4 also results in a lethal terminal phenotype characterized by multinucleate, elongated cells that fail to complete cytokinesis. Sequence comparisons suggest that Cdc4p may be a member of a new class of EF-hand proteins. Cdc4p localizes to a ringlike structure in the medial region of cells undergoing cytokinesis. Thus, Cdc4p appears to be an essential component of the F-actin contractile ring. We find that Cdc4 protein forms a complex with a 200-kD protein which can be cross-linked to UTP, a property common to myosin heavy chains. Together these results suggest that Cdc4p may be a novel myosin light chain.