S. pombe gene sds22+ essential for a midmitotic transition encodes a leucine-rich repeat protein that positively modulates protein phosphatase-1

Cell. 1991 Jan 11;64(1):149-57. doi: 10.1016/0092-8674(91)90216-l.


The fission yeast dis2+ gene encodes one of the two type 1 protein phosphatases (PP1) in this organism. Its semidominant mutant dis2-11 is defective in mitosis. Here we report the characterization of a high dosage suppressor, sds22+, that complements dis2-11. Sequencing of the cloned sds22+ gene predicts a novel 30 kd protein, which consists almost entirely of leucine-rich 22 amino acid repeats and is enriched in the insoluble nuclear fraction. sds22+ is an essential gene required for the mitotic metaphase/anaphase transition; gene disruption causes cell cycle arrest at midmitosis. Unexpectedly, the sds22+ gene becomes dispensable upon high dosage of the PP1 genes. The sds22+ product appears to facilitate PP1-dependent dephosphorylation, but does not substitute PP1. We propose that the sds22+ protein forms a repeating helical rod that is capable of enhancing a PP1-dependent dephosphorylation activity that is essential in midmitosis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Cycle Proteins
  • Fungal Proteins / genetics*
  • Genes, Fungal*
  • Genetic Complementation Test
  • Leucine*
  • Mitosis
  • Models, Genetic
  • Molecular Sequence Data
  • Nuclear Proteins*
  • Phosphoprotein Phosphatases / genetics*
  • Protein Conformation
  • Protein Phosphatase 1
  • Restriction Mapping
  • Schizosaccharomyces / enzymology
  • Schizosaccharomyces / genetics*
  • Schizosaccharomyces / growth & development
  • Schizosaccharomyces pombe Proteins*
  • Sequence Homology, Nucleic Acid


  • Cell Cycle Proteins
  • Fungal Proteins
  • Nuclear Proteins
  • Schizosaccharomyces pombe Proteins
  • sds22 protein, S pombe
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 1
  • Leucine

Associated data

  • GENBANK/D10288
  • GENBANK/D10289
  • GENBANK/D10290
  • GENBANK/M57495
  • GENBANK/S63143
  • GENBANK/S63144
  • GENBANK/S63145
  • GENBANK/S63146
  • GENBANK/S63147
  • GENBANK/S63148