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. 2006 Jun 14;397(Pt 1):39–45. doi: 10.1042/BJ20051957

Figure 5. Tiam1 regulates Rac-mediated Arp2/3-controlled actin polymerization.

Figure 5

The localization of Tiam1 to actin-rich structures at the plasma membrane could be accomplished by association of Tiam1 through the PHn-CC domain with the p21-Arc subunit of the Arp2/3 complex (1). Tiam1 activates Rac (2) that influences the actin nucleation activity of Arp2/3 by activating either WAVE or PAK1 [11,15] (3,4). As a result, the activated Arp2/3 complex associates with the actin cytoskeleton and induces actin polymerization (5). In this way Tiam1 and the Arp2/3 complex may collaborate in a positive-feedback loop to induce rapid and abundant actin polymerization at specific sites in cells.