This result indicated that it is the normal endogenous activity of RhoA and Rac1 that defines the efficiency of cell invasion by T. buy Wortmannin gondii tachyzoites, but not the amount of these proteins. This requirement is also reported in other intracellular pathogens. Shigella entry into HeLa cells induces membrane ruffling

at the bacterial entry site, and the three Rho isoforms were recruited into bacterial entry sites. This membrane folding caused by invasion was abolished by using a Rho-specific inhibitor, and bacterial entry was impaired accordingly [34]. Hela cells transfected with the dominant negative versions of Rac1 or RhoA reduced group B Streptococcus invasion by 75% and 51%, respectively, suggesting that Rho GTPases are indispensable for efficient invasion of HeLa cells by this bacterium [35]. In MDCK cells, RhoA and Rac1were activated during Trypanosoma cruzi invasion and then triggered the reorganization of F-actin cytoskeleton, especially distinct

in the invasion position on the cell membrane. The invasion of T. cruzi G strain extracellular amastigotes was specifically this website inhibited in Rac1-N17 dominant-negative cells [36, 37]. After the invasion of the rabbit corneal epithelial cells (SIRC) by Candida albicans, host cell actin filaments formed a rigid ring-like structure in the host cell. Immunochemical staining of actin and the expression of chimeric green fluorescent protein (GFP)-GTPases (RhoA, Rac1) showed the colocalization BCKDHB of the GTPases with actin at invasion and actin polymerization sites, but this colocalization was not seen in SIRC cells expressing a GFP-tagged dominant-negative mutant of GTPases. www.selleckchem.com/products/srt2104-gsk2245840.html Inhibition of invasion was observed in SIRC cells expressing dominant-negative mutants of Rac1

and RhoA GTPases [38]. These findings suggest that many pathogens may employ conserved pathways for invasion. The Rho and Rac cell signaling involved in the cytoskeleton reorganization triggered by T. gondii invasion When epithelial cells are stimulated by EGF, c-Src is activated by EGF-induced EGF receptor activation [39]. After the activation of c-Src, Ephexin, VAV-2 and Tiam 1 are rapidly phosphorylated by c-Src [40, 41]. Phosphorylation of Ephexin promotes its GTPase activity toward RhoA [42, 43], and RhoA downstream effector Rho-associated kinase ROCK directly phosphorylates LIM-kinases LIMK1 and LIMK2, which in turn phosphorylates actin-depolymerizing factor destrin and actin-associated protein cofilin [44]. ROCK2 kinase phosphorylates CRMP2, and the phosphorylation of CRMP2 reduces its tubulin-heterodimer binding and the promotion of microtubule assembly [45, 46]. Activation of VAV-2 activates RhoA and Rac1 [47]. Downstream of Rac1, p21-activated kinase 1 (PAK1) activates LIMK1, and regulates the actin cytoskeletal reorganization through the phosphorylation of the actin-depolymerizing factors cofilin and destrin and their actin-depolymerizing activities [48, 49].