活性泛素合成的作用：E1 和 E2 酶的角色
中文名称
通路描述
泛素单体从较大的前体加工，然后通过泛素与 E1 激活酶（UBA1 或 UBA6）的半胱氨酸残基之间形成硫酯键进行激活。随后，泛素被转移至 E2 连接酶活性位点的半胱氨酸残基（综述见 van Wijk and Timmers 2010, Kleiger and Mayor 2014, Stewart et al. 2016）。含有多个泛素单体的前体蛋白（多泛素）由 UBB 和 UBC 基因产生。由 UBA52 和 RPS27A 基因产生的前体蛋白含有一个与核糖体蛋白融合的泛素。蛋白酶 OTULIN 和 USP5 在多泛素加工中非常活跃，而蛋白酶 UCHL3、USP7 和 USP9X 切割泛素 - 核糖体蛋白前体，产生泛素单体（Grou et al. 2015）。其他酶也可能加工泛素前体。最终产生的泛素单体通过其 C 端甘氨酸的腺苷酸化激活，然后通过硫酯键与 E1 酶 UBA1 或 UBA6 的 C 端半胱氨酸连接（Jin et al. 2007，推断自兔同源物在 Haas et al. 1982, Hershko et al. 1983）。随后，泛素从 E1 酶转移到 E2 酶的一个半胱氨酸残基上（综述见 van Wijk and Timmers 2010, Stewart et al. 2016）。
英文描述
Synthesis of active ubiquitin: roles of E1 and E2 enzymes Ubiquitin monomers are processed from larger precursors and then activated by formation of a thiol ester bond between ubiquitin and a cysteine residue of an E1 activating enzyme (UBA1 or UBA6, Jin et al. 2007). The ubiquitin is then transferred to the active site cysteine residue of an E2 conjugating enzyme (reviewed in van Wijk and Timmers 2010, Kleiger and Mayor 2014, Stewart et al. 2016). Precursor proteins containing multiple ubiquitin monomers (polyubiquitins) are produced from the UBB and UBC genes. Precursors containing a single ubiquitin fused to a ribosomal protein are produced from the UBA52 and RPS27A genes. The proteases OTULIN and USP5 are very active in polyubiquitin processing, whereas the proteases UCHL3, USP7, and USP9X cleave the ubiquitin-ribosomal protein precursors yielding ubiquitin monomers (Grou et al. 2015). Other enzymes may also process ubiquitin precursors. A resultant ubiquitin monomer is activated by adenylation of its C-terminal glycine followed by conjugation of the C-terminus to a cysteine residue of the E1 enzymes UBA1 or UBA6 via a thiol ester bond (Jin et al. 2007, inferred from rabbit homologues in Haas et al. 1982, Hershko et al. 1983). The ubiquitin is then transferred from the E1 enzyme to a cysteine residue of one of several E2 enzymes (reviewed in van Wijk and Timmers 2010, Stewart et al. 2016).
所含基因
31 个基因