UBQLNs bind UIM-containing adaptor proteins

UBQLN proteins, also known as PLIC (protein linking IAP to cytoskeleton), are a family of four proteins with known roles in targeting ubiquitinated proteins to the proteasome (Mah et al, 2000; Kleijnen et al, 2000; Funakoshi et al, 2002). More recently, UBQLN proteins have been shown to play roles in the regulation of GPCR signaling (N'Diaye and Brown, 2003; Regan-Klapisz et al, 2005; N'Diaye et al, 2008). The ubiquitously expressed UBQLN1 and 2 both interact with UIM-domain containing proteins such as EPS15; the interaction is mediated by the UBQLN C-terminal UbL domain (Regan-Klapisz et al, 2005; N'Diaye et al, 2008). In the case of UBQLN2, interaction with UIM-containing proteins is required for UBQLN2 to negatively regulate clathrin-mediated endocytosis of GPCRs (N'Diaye et al, 2008).

UBQLN蛋白，亦称为PLIC（将IAP与细胞骨架链接的蛋白），是一组包含四种蛋白的家族，其在将泛素化蛋白靶向运送至蛋白酶体（Mah等，2000；Kleijnen等，2000；Funakoshi等，2002）中发挥着已知的作用。近期研究表明，UBQLN蛋白在G蛋白偶联受体（GPCR）信号通路的调控中亦扮演着重要角色（N'Diaye和Browning，2003；Regan-Klapisz等，2005；N'Diaye等，2008）。广泛表达的UBQLN1和2与包含UIM结构域的蛋白，如EPS15相互作用；此相互作用由UBQLN蛋白的C端UbL结构域介导（Regan-Klapisz等，2005；N'Diaye等，2008）。对于UBQLN2而言，与包含UIM的蛋白的相互作用对于其负向调控GPCR介导的内吞作用至关重要（N'Diaye等，2008）。