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

McCollum D, Balasubramanian MK, Pelcher LE, Hemmingsen SM, Gould KL
J Cell Biol. 1995 130 (3): 651-60

PMID: 7622565 · PMCID: PMC2120525 · 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. & 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.

MeSH Terms (23)

Amino Acid Sequence Base Sequence Cell Compartmentation Cell Cycle Proteins Cell Division Cloning, Molecular Cytoskeletal Proteins Escherichia coli F-Box Proteins Fluorescent Antibody Technique Fungal Proteins Genes, Fungal Molecular Sequence Data Mutation Phenotype Precipitin Tests Protein Binding Recombinant Proteins Schizosaccharomyces Schizosaccharomyces pombe Proteins Sequence Analysis, DNA Sequence Homology, Amino Acid Ubiquitin-Protein Ligases

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