Arrigoni Rachele, Alam Steven L, Wamstad Joseph A, Bardwell Vivian J, Sundquist Wesley I, Schreiber-Agus Nicole
Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Ullmann 809 Bronx, NY 10461, USA.
FEBS Lett. 2006 Nov 13;580(26):6233-41. doi: 10.1016/j.febslet.2006.10.027. Epub 2006 Oct 19.
The Rybp protein has been promoted as a Polycomb group (PcG)-associated protein, but its molecular function has remained elusive. Here we show that Rybp is a novel ubiquitin binding protein and is itself ubiquitinated. The Rybp interacting PcG protein Ring1B, a known ubiquitin E3 ligase, promotes Rybp ubiquitination. Moreover, one target of Rybp's ubiquitin binding domain appears to be ubiquitinated histone H2A; this histone is a substrate for Ring1B's E3 ligase activity in association with gene silencing processes. These findings on Rybp provide a further link between the ubiquitination system and PcG transcriptional repressors.
Rybp蛋白一直被认为是一种与多梳蛋白家族（PcG）相关的蛋白，但其分子功能仍不清楚。在此我们表明，Rybp是一种新型泛素结合蛋白，且其自身也会被泛素化。与Rybp相互作用的PcG蛋白Ring1B是一种已知的泛素E3连接酶，可促进Rybp的泛素化。此外，Rybp泛素结合结构域的一个靶点似乎是泛素化的组蛋白H2A；这种组蛋白是Ring1B的E3连接酶活性在基因沉默过程中的底物。这些关于Rybp的发现进一步揭示了泛素化系统与PcG转录抑制因子之间的联系。
