PDF(Pubmed)
Abstract：
Cullin (CUL)-RING (Really Interesting New Gene) E3 ubiquitin (Ub) ligases (CRLs) are the largest E3 family. The E3 CRL core ligase is a subcomplex formed by the CUL C-terminal domain bound with the ROC1/RBX1 RING finger protein, which acts as a hub that mediates and organizes multiple interactions with E2, Ub, Nedd8, and the ARIH family protein, thereby resulting in Ub transfer to the E3-bound substrate. This report describes the modulation of CRL-dependent ubiquitination by small molecule compounds including KH-4-43, #33, and suramin, which target the CRL core ligases. We show that both KH-4-43 and #33 inhibit the ubiquitination of CK1α by CRL4CRBN. However, either compound\'s inhibitory effect on this reaction is significantly reduced when a neddylated form of CRL4CRBN is used. On the other hand, both #33 and KH-4-43 inhibit the ubiquitination of β-catenin by CRL1β-TrCP and Nedd8-CRL1β-TrCP almost equally. Thus, neddylation of CRL1β-TrCP does not negatively impact the sensitivity to inhibition by #33 and KH-4-43. These findings suggest that the effects of neddylation to alter the sensitivity of CRL inhibition by KH-4-43/#33 is dependent upon the specific CRL type. Suramin, a compound that targets CUL\'s basic canyon, can effectively inhibit CRL1/4-dependent ubiquitination regardless of neddylation status, in contrast to the results observed with KH-4-43/#33. This observed differential drug sensitivity of KH-4-43/#33 appears to echo CUL-specific Nedd8 effects on CRLs as revealed by recent high-resolution structural biology efforts. The highly diversified CRL core ligase structures may provide opportunities for specific targeting by small molecule modulators.
摘要：
Cullin(CUL)-RING(真正有趣的新基因)E3泛素(Ub)连接酶(CRLs)是最大的E3家族。E3CRL核心连接酶是由与ROC1/RBX1RING指蛋白结合的CULC末端结构域形成的亚复合物，它作为一个枢纽，调解和组织与E2、Ub、Nedd8和ARIH家族蛋白，从而导致Ub转移到E3结合的底物。本报告描述了小分子化合物对CRL依赖性泛素化的调节，包括KH-4-43，#33和苏拉明，以CRL核心连接酶为目标。我们还显示KH-4-43和#33均抑制CRL4CRBN对CK1α的泛素化。然而,当使用Neddylated形式的CRL4CRBN时,任一化合物对该反应的抑制作用显著降低。另一方面,#33和KH-4-43几乎相等地抑制CRL1β-TrCP和Nedd8-CRL1β-TrCP对β-联蛋白的泛素化。因此，CRL1β-TrCP的neddylation化不会负面影响对#33和KH-4-43的抑制作用的敏感性。这些发现表明neddylation改变KH-4-43/#33对CRL抑制的敏感性的作用取决于具体的CRL类型。苏拉明,一种针对CUL基本峡谷的化合物，能有效抑制CRL1/4依赖的泛素化，无论Neddylation状态如何，与用KH-4-43/#33观察到的结果相反。观察到的KH-4-43/＃33的差异药物敏感性似乎反映了CUL特异性Nedd8对CRL的影响，如最近的高分辨率结构生物学研究所揭示的。高度多样化的CRL核心连接酶结构可以为小分子调节剂的特异性靶向提供机会。
