Flinn E M, Busch C M, Wright A P
Karolinska Institute, Department of Biosciences, NOVUM, S-14157 Huddinge, Sweden.
Mol Cell Biol. 1998 Oct;18(10):5961-9. doi: 10.1128/MCB.18.10.5961.
Cellular levels of the rapidly degraded c-myc protein play an important role in determining the proliferation status of cells. Increased levels of c-myc are frequently associated with rapidly proliferating tumor cells. We show here that myc boxes I and II, found in the N termini of all members of the myc protein family, function to direct the degradation of the c-myc protein. Both myc boxes I and II contain sufficient information to independently direct the degradation of otherwise stably expressed proteins to which they are fused. At least part of the myc box-directed degradation occurs via the proteasome. The mechanism of myc box-directed degradation appears to be conserved between yeast and mammalian cells. Our results suggest that the myc boxes may play an important role in regulating the level and activity of the c-myc protein.
快速降解的c-myc蛋白的细胞水平在决定细胞增殖状态中起重要作用。c-myc水平升高常与快速增殖的肿瘤细胞相关。我们在此表明，在myc蛋白家族所有成员的N末端发现的Myc框I和II，其功能是指导c-myc蛋白的降解。Myc框I和II都包含足够的信息来独立指导与其融合的原本稳定表达的蛋白质的降解。至少部分由Myc框指导的降解是通过蛋白酶体进行的。Myc框指导的降解机制在酵母和哺乳动物细胞之间似乎是保守的。我们的结果表明，Myc框可能在调节c-myc蛋白的水平和活性中起重要作用。
