Involvement of Plasmodium falciparum protein kinase CK2 in the chromatin assembly pathwayReportar como inadecuado

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BMC Biology

, 10:5

First Online: 31 January 2012Received: 27 December 2011Accepted: 31 January 2012


BackgroundProtein kinase CK2 is a pleiotropic serine-threonine protein kinase with hundreds of reported substrates, and plays an important role in a number of cellular processes. The cellular functions of Plasmodium falciparum CK2 PfCK2 are unknown. The parasite-s genome encodes one catalytic subunit, PfCK2α, which we have previously shown to be essential for completion of the asexual erythrocytic cycle, and two putative regulatory subunits, PfCK2β1 and PfCK2β2.

ResultsWe now show that the genes encoding both regulatory PfCK2 subunits PfCK2β1 and PfCK2β2 cannot be disrupted. Using immunofluorescence and electron microscopy, we examined the intra-erythrocytic stages of transgenic parasite lines expressing hemagglutinin HA-tagged catalytic and regulatory subunits HA-CK2α, HA-PfCK2β1 or HA-PfCK2β2, and localized all three subunits to both cytoplasmic and nuclear compartments of the parasite. The same transgenic parasite lines were used to purify PfCK2β1- and PfCK2β2-containing complexes, which were analyzed by mass spectrometry. The recovered proteins were unevenly distributed between various pathways, with a large proportion of components of the chromatin assembly pathway being present in both PfCK2β1 and PfCK2β2 precipitates, implicating PfCK2 in chromatin dynamics. We also found that chromatin-related substrates such as nucleosome assembly proteins Naps, histones, and two members of the Alba family are phosphorylated by PfCK2α in vitro.

ConclusionsOur reverse-genetics data show that each of the two regulatory PfCK2 subunits is required for completion of the asexual erythrocytic cycle. Our interactome study points to an implication of PfCK2 in many cellular pathways, with chromatin dynamics being identified as a major process regulated by PfCK2. This study paves the way for a kinome-wide interactomics-based approach to elucidate protein kinase function in malaria parasites.

Electronic supplementary materialThe online version of this article doi:10.1186-1741-7007-10-5 contains supplementary material, which is available to authorized users.

Eeshita G Dastidar, Guillem Dayer, Zoe M Holland contributed equally to this work.

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Autor: Eeshita G Dastidar - Guillem Dayer - Zoe M Holland - Dominique Dorin-Semblat - Aurélie Claes - Arnaud Chêne - Amit Shar


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