Complex formation, phosphorylation, and localization of protein kinase A of Schizosaccharomyces pombe upon glucose starvation

Biosci Biotechnol Biochem. 2011;75(8):1456-65. doi: 10.1271/bbb.110125.


Nine sam mutants that undergo sexual differentiation without requiring starvation in Schizosaccharomyces pombe were previously isolated. In this study, we identified a nonsense mutation on the pka1 locus in the sam6 mutant. pka1 encodes a catalytic subunit of protein kinase A (PKA). Replacement and overexpression of pka1 suppressed the KCl sensitivity and hyper-mating phenotype of sam6, confirming that sam6 is an allele of pka1. To characterize further the regulation of Pka1, we tested the physical interaction between Pka1 and Cgs1 (a regulatory subunit of PKA). Pka1 and Cgs1 physically interacted under glucose-limited conditions but not under glucose-rich conditions. In addition, the formation of a Pka1-Cgs1 complex was detected under glucose-limited conditions by Blue Native PAGE. Furthermore, the Pka1 protein was found to be phosphorylated under glucose-starved conditions, and at the same time its localization shifted from the nucleus towards the cytoplasm (mainly the vacuoles), suggesting a strong relationship among phosphorylation, complex formation, and the cytoplasmic distribution of Pka1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Codon, Nonsense
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Cytoplasm / genetics
  • Cytoplasm / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Gene Expression Regulation, Fungal / drug effects
  • Gene Expression Regulation, Fungal / genetics*
  • Genetic Association Studies
  • Genotype
  • Glucose / deficiency*
  • Immunoprecipitation
  • Molecular Sequence Data
  • Phenotype
  • Phosphorylation / drug effects
  • Phosphorylation / genetics
  • Plasmids
  • Potassium Chloride / metabolism
  • Potassium Chloride / pharmacology
  • Protein Binding
  • Protein Subunits / genetics
  • Protein Subunits / metabolism*
  • Schizosaccharomyces / enzymology*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Signal Transduction / genetics*
  • Transduction, Genetic


  • Codon, Nonsense
  • Protein Subunits
  • Schizosaccharomyces pombe Proteins
  • Potassium Chloride
  • Cyclic AMP-Dependent Protein Kinases
  • Glucose