Figures & data
Figure 1. E3 ubiquitin ligases regulate stress fiber, lamellipodium and focal adhesion dynamics. (1) Both Smurf1 and Cul3/BACURD ubiquitinate RhoA to regulate stress fiber formation and cell polarity, whereas ASB2α ubiquitinates Filamins to modulate the elasticity of the actin network and consequently cell spreading. The activity of Smurf1 is regulated by APC/Cdh1 E3 and CKIP-1. (2) Rac1 is ubiquitinated by a number of E3 ubiquitin ligases, including HACE1, XIAP, and SCF/FBX19, resulting in Rac1 degradation and reduction in lamellipodium extension. On the other hand, sumoylation of Rac1 by PIAS3, a SUMO ligase, stimulates its activation and lamellipodium protrusions. Smurf1-mediated ubiquitination of TRAF4 also promotes Rac1 activation. (3) PIPKIγ90 is ubiquitinated at K97 by HECTD1, resulting its degradation and FA assembly/disassembly during cell migration. Smurf1 binds to TH and causes TH ubiquitination and degradation, consequently leading to FA disassembly.
