G0 期和早期 G1 期
中文名称
通路描述
在静止细胞中，p130（RBL2）与 E2F4 或 E2F5 结合，并与 DP1 或 DP2 结合，与 MuvB 复合物结合，形成进化上保守的 DREAM 复合物，抑制细胞周期基因的转录。在活跃循环细胞的早期 G1 期，p107（RBL1）与 E2F4 和 DP1 或 DP2 形成复合物，抑制 E2F 靶基因的转录。p130（RBL2）和 p107（RBL1）通过招募 HDAC1（组蛋白去乙酰化酶 1），可能与其他染色质修饰酶结合，来抑制 E2F 靶基因的转录。p107（RBL1）的表达受细胞周期调节，其水平在晚期 G1 期和 S 期达到峰值。尽管 p107（RBL1）在晚期 G1 期被周期素 D 关联激酶磷酸化，但认为在整个 G1 期和 S 期都存在一小部分 p107（RBL1），可能参与调节 S 期基因的转录。研究表明，与 RB1 和 p130（RBL2）不同，当 p107（RBL1）过表达时，可以阻滞细胞周期在 G1 和 S 期。关于 p107、p130 和 pocket 蛋白功能的最新综述，请参阅 Wirt 和 Sage, 2010, MacPherson 2008 和 Cobrinik 2005。
英文描述
G0 and Early G1 In G0 and early G1 in quiescent cells, p130 (RBL2) bound to E2F4 or E2F5 and either DP1 or DP2, associates with the MuvB complex, forming an evolutionarily conserved DREAM complex, that represses transcription of cell cycle genes. During early G1 phase in actively cycling cells, p107 (RBL1) forms a complex with E2F4 and DP1 or DP2 and represses transcription of E2F target genes. Both p130 (RBL2) and p107 (RBL1) repress transcription of E2F targets through recruiting histone deacetylase HDAC1, possibly in complex with other chromatin modifying enzymes, to E2F-regulated promoters. Expression of p107 (RBL1) is cell cycle regulated, with its levels peaking in late G1 and S phase. Although p107 (RBL1) is phosphorylated by cyclin D assocaited kinases during late G1 phase, a small pool of p107 (RBL1) is thought to be present throughout G1 and S phase, and could be involved in fine tuning the transcription of S-phase genes. This is supported by studies showing that unlike RB1 and p130 (RBL2), which are able to induce G1 arrest when over-expressed, p107 (RBL1) over-expression can arrest the cell cycle in both G1 and S phase. For recent reviews on the function of p107, p130 and pocket proteins in general, please refer to Wirt and Sage, 2010, MacPherson 2008 and Cobrinik 2005.
所含基因
18 个基因