Phosphorylation of helix-loop-helix proteins ID1, ID2 and ID3.
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.
Nagata
Y
Y
Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan.
Shoji
W
W
Obinata
M
M
Todokoro
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D016203:CDC2 Protein Kinase / Q000378:metabolism; D047390:Casein Kinase II; D000242:Cyclic AMP / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D018257:Helix-Loop-Helix Motifs; D007163:Immunosorbent Techniques; D051798:Inhibitor of Differentiation Protein 1; D051797:Inhibitor of Differentiation Protein 2; D051796:Inhibitor of Differentiation Proteins; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012097:Repressor Proteins; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*
D004268:DNA-Binding Proteins; D051798:Inhibitor of Differentiation Protein 1; D051797:Inhibitor of Differentiation Protein 2; D051796:Inhibitor of Differentiation Proteins; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D012097:Repressor Proteins; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; C553060:Tcf7l1 protein, rat; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; C075640:ID3 protein, human; D004247:DNA; D000242:Cyclic AMP; D011494:Protein Kinases; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D016203:CDC2 Protein Kinase