Phosphoproteomics profiling suggests a role for nuclear βΙPKC in transcription processes of undifferentiated murine embryonic stem cells

J Proteome Res. 2010 Dec 3;9(12):6191-206. doi: 10.1021/pr100355k. Epub 2010 Nov 1.


Protein kinase C (PKC) plays a key role in embryonic stem cell (ESC) proliferation, self-renewal, and differentiation. However, the function of specific PKC isoenzymes have yet to be determined. Of the PKCs expressed in undifferentiated ESCs, βIPKC was the only isoenzyme abundantly expressed in the nuclei. To investigate the role of βΙPKC in these cells, we employed a phosphoproteomics strategy and used two classical (cPKC) peptide modulators and one βIPKC-specific inhibitor peptide. We identified 13 nuclear proteins that are direct or indirect βΙPKC substrates in undifferentiated ESCs. These proteins are known to be involved in regulating transcription, splicing, and chromatin remodeling during proliferation and differentiation. Inhibiting βΙPKC had no effect on DNA synthesis in undifferentiated ESCs. However, upon differentiation, many cells seized to express βΙPKC and βΙPKC was frequently found in the cytoplasm. Taken together, our results suggest that βIPKC takes part in the processes that maintain ESCs in their undifferentiated state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • Cell Differentiation
  • Cell Line
  • Cell Nucleus / metabolism
  • Electrophoresis, Gel, Two-Dimensional
  • Embryonic Stem Cells / cytology
  • Embryonic Stem Cells / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Gene Expression
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Mass Spectrometry
  • Mice
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism
  • Peptides / pharmacology
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Protein Kinase C beta
  • Proteomics / methods*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Substrate Specificity
  • Transcription, Genetic


  • Enzyme Inhibitors
  • Isoenzymes
  • Nuclear Proteins
  • Peptides
  • Phosphoproteins
  • Protein Kinase C
  • Protein Kinase C beta