Hori T, Osaka F, Chiba T, Miyamoto C, Okabayashi K, Shimbara N, Kato S, Tanaka K
Tokyo Metropolitan Institute of Medical Science, Japan.
Oncogene. 1999 Nov 18;18(48):6829-34. doi: 10.1038/sj.onc.1203093.
Recently we found that NEDD8, a ubiquitin-like protein, was linked covalently to human cullin-4A (abbreviated Cul-4A) by a new ubiquitin-related pathway that is analogous to but distinct from the ligating system for SUMO1, another ubiquitin-like protein. However, it remained unknown whether the other five members of the family of human cullin/Cdc53 proteins are modified by NEDD8. Here we report that all Hs-Cul family proteins, such as Cul-1, Cul-2, Cul-3, Cul-4B, and Cul-5, in addition to Cul-4A, were modified by covalent attachment of NEDD8 in rabbit reticulocyte lysates. Moreover, by comprehensive Northern-blot analyses, we examined multiple tissue distributions of the messages for all Cul-family proteins, NEDD8, and the NEDD8-ligating system consisting of APP-BP1/hUba3, and hUbc12, which function as E1- and E2-like enzymes, respectively. The expressions of Cul-1, Cul-2, and Cul-3 resembled each other and were apparently correlated to those of NEDD8 and the NEDD8-ligating system in various human cells and tissues. However, the mRNA levels of Cul-4A, Cul-4B, and Cul-5 differed considerably from each other as well as from other Cul-family proteins. The enhanced expression of all Cul-family proteins except Cul-5 was observed in a variety of tumor cell lines.
最近我们发现，一种类泛素蛋白NEDD8通过一条新的泛素相关途径与人类cullin-4A（简称Cul-4A）共价连接，该途径类似于但不同于另一种类泛素蛋白SUMO1的连接系统。然而，人类cullin/Cdc53蛋白家族的其他五个成员是否被NEDD8修饰仍不清楚。在此我们报告，除了Cul-4A外，所有Hs-Cul家族蛋白，如Cul-1、Cul-2、Cul-3、Cul-4B和Cul-5，在兔网织红细胞裂解物中都被NEDD8共价连接修饰。此外，通过全面的Northern印迹分析，我们检测了所有Cul家族蛋白、NEDD8以及由分别作为类E1和类E2酶发挥作用的APP-BP1/hUba3和hUbc12组成的NEDD8连接系统的多种组织分布情况。Cul-1、Cul-2和Cul-3的表达彼此相似，并且在各种人类细胞和组织中明显与NEDD8及NEDD8连接系统的表达相关。然而，Cul-4A、Cul-4B和Cul-5的mRNA水平彼此之间以及与其他Cul家族蛋白有很大差异。在多种肿瘤细胞系中观察到除Cul-5外所有Cul家族蛋白的表达增强。
