title: Molecular analyses of Toxoplasma gondii calmodulin-like domain protein kinase isoform 3.
abstract: Ca(2+) signaling is thought to play an important role in Toxoplasma gondii motility, including invasion of and egress from host cells. Recently, it has been reported that phosphorylation of the glideosome apparatus components of T. gondii occurs during invasion. To elucidate the role of T. gondii calmodulin-like domain protein kinase in the signaling pathway that bridges Ca(2+) stimulation and motility, we characterized T. gondii calmodulin-like domain protein kinase isoform 3 (TgCDPKif3). TgCDPKif3 is homologous to Plasmodium falciparum calcium-dependent protein kinase 1, which has been reported to phosphorylate P. falciparum glideosome components. TgCDPKif3 was purified as a fusion protein that was labeled with [gamma-(32)P]ATP, and the label was subsequently removed by phosphatase treatment. Phosphorylation was eliminated when the putative catalytic lysine residue of TgCDPKif3 was replaced with alanine. TgCDPKif3 phosphorylated Histone II(AS) as a representative substrate in a Ca(2+)-dependent manner at a high Ca(2+) concentration. TgCDPKif3 was localized to the apical ends of tachyzoites. TgCDPKif3 showed the translocation between intra- and extracellular tachyzoites. TgCDPKif3 could phosphorylate T. gondii aldolase 1 (TgALD1) in vitro. The interaction between TgCDPKif3 and TgALD1 was confirmed by the co-immunoprecipitation assay in mammal cells. We suggested that TgCDPKif3 could participate in the motility of T. gondii through the phosphorylation of glideosome complex member.
authors.affiliation: Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Sugi
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kato
authors.forename: Kyousuke
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Kishor
authors.initials: K
authors.lastname: Pandey
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Takemae
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kurokawa
authors.forename: Yukinobu
authors.initials: Y
authors.lastname: Tohya
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Akashi
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000201:enzymology / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D015800:Protozoan Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D018411:Spodoptera; D014122:Toxoplasma / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D014709:Vero Cells
chemical_list: D007527:Isoenzymes; D015800:Protozoan Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium