Mettouchi Amel, Lemichez Emmanuel
INSERM, U634, Faculté de Médecine de Nice, Nice, France.
Small GTPases. 2012 Apr-Jun;3(2):102-6. doi: 10.4161/sgtp.19221.
Rho GTPases undergo ubiquitylation and degradation via the ubiquitin-proteasome pathway. We now report in the November issue of Developmental Cell that the E3 ubiquitin-ligase HACE1 catalyzes the ubiquitylation of GTP-bound Rac1. Depletion of HACE1 leads to an increase of Rac1 activity. We have proposed that HACE1 limits Rac1 activity in cells, a regulation that is usurped by some pathogenic bacteria for efficient invasion of host cell monolayers. We here review these findings in parallel with the regulation of RhoA by the ubiquitin and proteasome system (UPS) and discuss the impact of these regulations on the capacity of Rho GTPases to signal.
Rho GTP酶通过泛素-蛋白酶体途径发生泛素化并降解。我们现在在《发育细胞》11月刊上报道，E3泛素连接酶HACE1催化结合GTP的Rac1的泛素化。HACE1的缺失导致Rac1活性增加。我们提出，HACE1限制细胞中的Rac1活性，而一些致病细菌会利用这种调节来有效侵袭宿主细胞单层。我们在此结合泛素和蛋白酶体系统（UPS）对RhoA的调节来综述这些发现，并讨论这些调节对Rho GTP酶信号传导能力的影响。
