Schizosaccharomyces pombe cdc4+ gene encodes a novel EF-hand protein essential for cytokinesis.
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.
McCollum
D
D
Howard Hughes Medical Institute, Vanderbilt University, Nashville, Tennessee 37232, USA.
Balasubramanian
M K
MK
Pelcher
L E
LE
Hemmingsen
S M
SM
Gould
K L
KL
D000595:Amino Acid Sequence; D001483:Base Sequence; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D002455:Cell Division / Q000235:genetics*; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D004926:Escherichia coli / Q000235:genetics; D044783:F-Box Proteins; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D005800:Genes, Fungal / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011233:Precipitin Tests; D011485:Protein Binding; D011994:Recombinant Proteins / Q000096:biosynthesis; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D044767:Ubiquitin-Protein Ligases
D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D044783:F-Box Proteins; D005656:Fungal Proteins; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; C513274:cdc4 protein, S pombe; D044767:Ubiquitin-Protein Ligases