Phosphorylation of helix-loop-helix proteins ID1, ID2 and ID3

Yuka Nagata, Wataru Shoji, Masuo Obinata, Kazuo Todokoro

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Id is a helix-loop-helix protein which forms heterodimer with ubiquitous and/or tissue-specific basic helix-loop-helix proteins and inhibits their DNA binding. It has been noted that putative phosphorylation sites for various protein kinases exist in rat Id1, Id2 and Id3. We show here that Id1 and Id2 can be phosphorylated in vitro by cAMP-dependent protein kinase, Id2 and Id3 by cdc2 kinase, and all three Ids by protein kinase C. The phosphorylated Id1 was actually immunoprecipitated in nerve-growth-factor-stimulated PC12 cells. Gel mobility shift assays, however, demonstrated that neither phosphorylation of Id proteins by cAMP-dependent protein kinase nor phosphorylation of E47 by protein kinase C affected the inhibition of E47 homodimer formation and its DNA binding. Taken together with other observations, phosphorylation of Id proteins may play a role in regulation of cell differentiation but not directly in the dimerization and DNA binding.

Original languageEnglish
Pages (from-to)916-926
Number of pages11
JournalBiochemical and biophysical research communications
Issue number3
Publication statusPublished - 1995 Feb 27

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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