Send to

Choose Destination
Mol Cell. 1999 Dec;4(6):1087-92.

Phosphorylation of rat serine 105 or mouse threonine 217 in C/EBP beta is required for hepatocyte proliferation induced by TGF alpha.

Author information

Salk Institute for Biological Studies, La Jolla, California 92037, USA.


We report that TGF alpha induces activation of the p90 ribosomal S kinase (RSK), which results in the phosphorylation of rat C/EBP beta on Ser-105 and of mouse C/EBP beta on Thr-217 and concomitantly stimulates proliferation in differentiated hepatocytes. Moreover, C/EBP beta-/- mouse hepatocytes respond to TGF alpha when wild-type C/EBP beta is reexpressed, whereas they remain refractory to the growth effect of TGF alpha when expressing phosphoacceptor mutants rat C/EBP beta Ala-105 or mouse C/EBP beta Ala-217. In contrast, C/EBP beta-/- hepatocytes expressing the phosphorylation mimic mutants, rat C/EBP beta Asp-105 or mouse C/EBP beta Glu-217, exhibited marked proliferation in the absence of TGF alpha. Thus, a site-specific phosphorylation of the transcription factor C/EBP beta is critical for hepatocyte proliferation induced by TGF alpha and other stimuli that activate RSK.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center