The deubiquitinating enzyme Ubp21p of fission yeast stabilizes a mutant form of protein kinase Prp4p

Mol Genet Genomics. 2002 Mar;267(1):88-95. doi: 10.1007/s00438-002-0639-8. Epub 2002 Feb 8.


The protein kinase Prp4p of Schizosaccharomyces pombe is involved in control of the formation of active spliceosomes, phosphorylating the spliceosomal component Prp1p. The kinase domain of Prp4p is closely related to cyclin-dependent kinases (CDKs) and mitogen-activated kinases (MAPKs). A mutational analysis of the highly conserved amino acid sequence ALKHP in subdomain XI of this kinase showed that structural features of this sequence are important for the function of the kinase. We identified ubp21 as a high-copy-number suppressor of a mutation in the ALKHP motif. Characterization of this gene revealed that it encodes a deubiquitinating enzyme belonging to the family of ubiquitin-specific processing proteases (Ubps). The results presented in this report are consistent with the notion that the deubiquitinating activity of Ubp21p may be involved in regulating the steady-state levels of proteins including Prp4p.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Endopeptidases / chemistry
  • Endopeptidases / genetics
  • Endopeptidases / physiology*
  • Enzyme Stability
  • Fungal Proteins / metabolism*
  • Genes, Fungal
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Protein Kinases / metabolism*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces / growth & development
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / chemistry
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / physiology*
  • Sequence Homology, Amino Acid
  • Ubiquitin / metabolism*


  • Fungal Proteins
  • Schizosaccharomyces pombe Proteins
  • Ubiquitin
  • Protein Kinases
  • Endopeptidases
  • ubp15 protein, S pombe