01514naa a2200133 a 450000100080000000500110000800800410001910000110006024501420007126000090021352010730022265300130129577300720130810772942011-06-07       2010    bl uuuu     u00u1 u    #d1 aEpagri  aPhosphoproteomics profiling suggests a role for nuclear ?IPKC in transcription processes of undifferentiated murine embryonic stem cells.  c2010  aProtein 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, ??IPKC was the only isoenzyme abundantly expressed in the nuclei. To investigate the role of ????PKC in these cells, we employed a phosphoproteomics strategy and used two classical (cPKC) peptide modulators and one ??IPKC-specific inhibitor peptide. We identified 13 nuclear proteins that are direct or indirect ????PKC substrates in undifferentiated ESCs. These proteins are known to be involved in regulating transcription, splicing, and chromatin remodeling during proliferation and differentiation. Inhibiting ????PKC had no effect on DNA synthesis in undifferentiated ESCs. However, upon differentiation, many cells seized to express ????PKC and ????PKC was frequently found in the cytoplasm. Taken together, our results suggest that ??IPKC takes part in the processes that maintain ESCs in their undifferentiated state.  aProteoma  tJournal of Proteome Research, EEUgv. 9, n. 12, p. 6191-6206, 2010.