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Publication Abstract from PubMed

Rho family GTPases modulate actin cytoskeleton dynamics by signaling through multiple effectors, including the p21-activated kinases (PAKs). The intestinal parasite Entamoeba histolytica expresses approximately 20 Rho family GTPases and seven isoforms of PAK, two of which have been implicated in pathogenesis-related processes such as amoebic motility and invasion and host cell phagocytosis. Here, we describe two previously unstudied PAK isoforms, EhPAK4 and EhPAK5, as highly specific effectors of EhRacC. A structural model based on 2.35 A X-ray crystallographic data of a complex between EhRacC(Q65L).GTP and the EhPAK4 p21 binding domain (PBD) reveals a fairly well-conserved Rho/effector interface despite deviation of the PBD alpha-helix. A structural comparison with EhRho1 in complex with EhFormin1 suggests likely determinants of Rho family GTPase signaling specificity in E. histolytica. These findings suggest a high degree of Rho family GTPase diversity and specificity in the single-cell parasite E. histolytica. Because PAKs regulate pathogenesis-related processes in E. histolytica, they may be valid pharmacologic targets for anti-amoebiasis drugs.

Entamoeba histolytica RacC Selectively Engages p21-Activated Kinase Effectors.,Bosch DE, Siderovski DP Biochemistry. 2015 Jan 20;54(2):404-12. doi: 10.1021/bi501226f. Epub 2015 Jan 2. PMID:25529118^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.