Musti A M, Treier M, Peverali F A, Bohmann D
EMBL, Heidelberg, Germany.
Biol Chem. 1996 Oct;377(10):619-24. doi: 10.1515/bchm3.1996.377.10.619.
c-Jun and JunD are two closely related members of the Jun family of transcription factors which markedly differ in their biological functions. Whereas c-Jun behaves as a positive regulator of cell growth and may cause cell transformation when overexpressed, JunD antagonizes both of these effects. To better understand how the activities of c-Jun and JunD are controlled, we investigated how their stabilities within the cell are determined. We show that, in contrast to c-Jun which is degraded following multi ubiquitination, JunD is not efficiently ubiquitinated and exhibits a correspondingly longer half-life. Mutational analysis reveals that the determinant for the difference in ubiquitination resides in the NH2-terminal regions of the proteins which in c-Jun contains the delta-domain.
c-Jun和JunD是转录因子Jun家族中两个密切相关的成员，它们的生物学功能明显不同。c-Jun作为细胞生长的正调节因子，过度表达时可能导致细胞转化，而JunD则拮抗这两种作用。为了更好地理解c-Jun和JunD的活性是如何被调控的，我们研究了它们在细胞内的稳定性是如何决定的。我们发现，与多聚泛素化后被降解的c-Jun不同，JunD不能有效地被泛素化，因此具有相应更长的半衰期。突变分析表明，泛素化差异的决定因素位于蛋白质的NH2末端区域，在c-Jun中该区域包含δ结构域。
