title: A C2 domain protein kinase initiates phagocytosis in the protozoan parasite Entamoeba histolytica.
abstract: Phagocytosis is a process whereby particles are taken in by cells through mechanisms superficially similar to those for endocytosis. It serves a wide range of functions, from providing nutrition in unicellular organisms to initiation of both innate and adaptive immunity in vertebrates. In the protozoan parasite Entamoeba histolytica, it has an essential role in survival and pathogenesis. In this study, we show that EhC2PK, a C2-domain-containing protein kinase, and the Ca²(+) and actin-binding protein, EhCaBP1, are involved in the initiation of phagocytosis in E. histolytica. Conditional suppression of EhC2PK expression and overexpression of a mutant form reveals its role in the initiation of phagocytic cups. EhC2PK binds phosphatidylserine in the presence of Ca²(+) and thereby recruits EhCaBP1 and actin to the membrane. Identification of these proteins in phagocytosis is an important step in amoebic biology and these molecules could be the important targets for developing novel therapies against amoebiasis.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
authors.lastname: Somlata
authors.forename: Sudha
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: Alok
authors.initials: A
authors.lastname: Bhattacharya
mesh_terms: D000199:Actins / Q000378:metabolism; D000562:Amebiasis / Q000188:drug therapy / Q000469:parasitology; D000818:Animals; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004748:Entamoeba histolytica / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D004912:Erythrocytes / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D006801:Humans; D058990:Molecular Targeted Therapy; D010587:Phagocytosis; D010588:Phagosomes / Q000378:metabolism* / Q000648:ultrastructure; D010718:Phosphatidylserines / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D000199:Actins; D000981:Antiprotozoal Agents; D002135:Calcium-Binding Proteins; D010718:Phosphatidylserines; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D011494:Protein Kinases; C085577:Ca2+-binding protein-1; D002118:Calcium