AUTHOR=Zhang Qiang , Guo Yaqiong , Li Na , Li Yu , Su Jiayuan , Xu Rui , Zhang Ziding , Feng Yaoyu , Xiao Lihua 

TITLE=Characterization of Calcium-Dependent Protein Kinases 3, a Protein Involved in Growth of Cryptosporidium parvum

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00907

DOI=10.3389/fmicb.2020.00907

ISSN=1664-302X

ABSTRACT=<p>Calcium-dependent protein kinases (CDPKs) are considered promising targets for pharmaceutical intervention of cryptosporidiosis. Whole-genome sequencing has revealed the presence of several CDPKs (<italic>Cp</italic>CDPKs) in <italic>Cryptosporidium parvum</italic>. In this study, we expressed recombinant <italic>Cp</italic>CDPK3 encoded by the <italic>cgd5_820</italic> gene in <italic>Escherichia coli</italic>. The biologic characteristics and functions of <italic>Cp</italic>CDPK3 were examined using qRT-PCR, immunofluorescence microscopy, and <italic>in vitro</italic> neutralization assay. The expression of the <italic>cgd5_820</italic> gene peaked in merozoites during <italic>in vitro</italic> culture while the <italic>Cp</italic>CDPK3 protein was expressed in both sporozoites and merozoites. Polyclonal antibodies against <italic>Cp</italic>CDPK3 showed no significant inhibitory effects on host invasion by the parasites. We assessed the inhibitory effects of 46 candidate compounds from molecular docking of <italic>Cp</italic>CDPK3 on both <italic>C. parvum</italic> development and <italic>Cp</italic>CDPK3 enzyme activities. One compound was identified to be effective. Results of these analyses suggest that <italic>Cp</italic>CDPK3 might play an important role in the growth of <italic>C. parvum</italic>.</p>