Characterization of Calcium-Dependent Protein Kinase 2A, a Potential Drug Target Against Cryptosporidiosis

Calcium-dependent protein kinases (CDPKs) are important in calcium influx, triggering several biological processes in spp. As they are not present in mammals, CDPKs are considered promising drug targets. Recent studies have characterized CDPK1, CDPK3, CDPK4, CDPK5, CDPK6, and CDPK9, but the role of CPK2A remains unclear. In this work, we expressed recombinant CDPK2A encoded by the cgd2_1060 gene in and characterized the biologic functions of CDPK2A using qRT-PCR, immunofluorescence microscopy, immuno-electron microscopy, and neutralization. The results revealed that CDPK2A protein was highly expressed in the apical region of sporozoites and merozoites and in macrogamonts. Monoclonal or polyclonal antibodies against CDPK2A failed to block the invasion of host cells. Among the 44 candidate inhibitors from molecular docking of CDPK2A, one inhibitor was identified as having a potential effect on both growth and CDPK2A enzyme activities. These data suggest that CDPK2A may play some roles during the development of and might be a potential drug target against cryptosporidiosis.