EhPAK, a member of the p21-activated kinase family, is involved in the control of Entamoeba histolytica migration and phagocytosis.
Entamoeba histolytica migration is essential for the development of amoebiasis, a human disease characterised by invasion and destruction of tissues. Amoebic motility requires both polarisation of the cell and formation of a predominant pseudopod. As p21-activated kinases PAKs are known to regulate eukaryotic cell motility and morphology, we investigated the role of PAK in E. histolytica. We showed that the C-terminal domain of EhPAK comprised a constitutive kinase activity in vitro and that overproduction of this fragment, in E. histolytica, caused a significant reduction in amoeboid migration, as measured by dynamic image analysis, indicating an involvement of EhPAK in this process. A dramatic loss of polarity, as indicated by the increased number of membrane extensions all around E. histolytica, was also observed, suggesting that the N-terminal domain of EhPAK was necessary for maintenance of cell polarity. To support this view, we showed that despite the absence of the consensus motif to bind to Rac and Cdc42, the N-terminal domain of EhPAK bound to Rac1, suggesting that the N-terminal region was a regulatory domain. In addition, we also found an increased rate of human red blood cell phagocytosis, suggesting for the first time an active role for a PAK protein in this process. Taking together, the results suggest strongly that EhPAK is a key regulatory element in polarity, motility and phagocytosis of E. histolytica.
Labruyère
Elisabeth
E
Unité de Biologie Cellulaire du Parasitisme, INSERM U389, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France. elabruye@pasteur.fr
Zimmer
Christophe
C
Galy
Vincent
V
Olivo-Marin
Jean-Christophe
JC
Guillén
Nancy
N
D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D002451:Cell Compartmentation / Q000235:genetics; D002465:Cell Movement / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics; D048429:Cell Size / Q000235:genetics; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D004748:Entamoeba histolytica / Q000166:cytology / Q000201:enzymology*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics / Q000302:isolation & purification*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000302:isolation & purification*; D017434:Protein Structure, Tertiary / Q000235:genetics; D011554:Pseudopodia / Q000201:enzymology* / Q000648:ultrastructure; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000235:genetics; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; D011494:Protein Kinases; C477149:PAK protein, Entamoeba histolytica; C515903:PAK1 protein, human; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein