Degradation of c-Fos by the 26S proteasome is accelerated by c-Jun and multiple protein kinases.

摘要: c-Fos is associated with c-Jun to increase the transcription of a number target genes and nuclear proto-oncoprotein very short half-life. This instability may be important in regulation normal cell cycle. Here we report mechanism for degradation c-Fos. Coexpression HeLa cells caused marked c-Fos, whereas v-Fos, retroviral counterpart was stable irrespective coexpression c-Jun. Interestingly, deletion C-terminal PEST region which altered v-Fos by frameshift mutation, greatly enhanced its stability, loss effect on stability. synthesized vitro degraded 26S proteasome ubiquitin-dependent fashion. Simple association had no but additions three protein kinases, mitogen-activated kinase, casein kinase II, CDC2 resulted acceleration proteasome-ubiquitin system, though only presence In contrast, truncated motif were not degraded, suggesting that they escaped from down-regulation breakdown. These findings indicate new oncogenic pathway induced acquisition intracellular stability cycle modulatory factor.