Identification of Toxoplasma gondii cAMP dependent protein kinase and its role in the tachyzoite growth

Hitomi Kurokawa, Kentaro Kato, Tatsuya Iwanaga, Tatsuki Sugi, Atsushi Sudo, Kyousuke Kobayashi, Haiyan Gong, Hitoshi Takemae, Frances C. Recuenco, Taisuke Horimoto, Hiroomi Akashi

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23 Citations (Scopus)


Background: cAMP-dependent protein kinase (PKA) has been implicated in the asexual stage of the Toxoplasma gondii life cycle through assaying the effect of a PKA-specific inhibitor on its growth rate. Since inhibition of the host cell PKA cannot be ruled out, a more precise evaluation of the role of PKA, as well as characterization of the kinase itself, is necessary. Methodology/Principal Finding: The inhibitory effects of two PKA inhibitors, H89, an ATP-competitive chemical inhibitor, and PKI, a substrate-competitive mammalian natural peptide inhibitor, were estimated. In the in vitro kinase assay, the inhibitory effect of PKI on a recombinant T. gondii PKA catalytic subunit (TgPKA-C) was weaker compared to that on mammalian PKA-C. In a tachyzoite growth assay, PKI had little effect on the growth of tachyzoites, whereas H89 strongly inhibited it. Moreover, T. gondii PKA regulatory subunit (TgPKA-R)-overexpressing tachyzoites showed a significant growth defect. Conclusions/Significance: Our data suggest that PKA plays an important role in the growth of tachyzoites, and the inhibitory effect of substrate-competitive inhibitor PKI on T. gondii PKA was low compared to that of the ATP competitive inhibitor H89.

Original languageEnglish
Article numbere22492
JournalPloS one
Issue number7
Publication statusPublished - 2011
Externally publishedYes

ASJC Scopus subject areas

  • General


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