Abstract
Calcium-dependent protein kinases (CDPKs) are considered promising targets for pharmaceutical intervention of cryptosporidiosis. Whole-genome sequencing has revealed the presence of several CDPKs (CpCDPKs) in Cryptosporidium parvum. In this study, we expressed recombinant CpCDPK3 encoded by the cgd5_820 gene in Escherichia coli. The biologic characteristics and functions of CpCDPK3 were examined using qRT-PCR, immunofluorescence microscopy, and in vitro neutralization assay. The expression of the cgd5_820 gene peaked in merozoites during in vitro culture while the CpCDPK3 protein was expressed in both sporozoites and merozoites. Polyclonal antibodies against CpCDPK3 showed no significant inhibitory effects on host invasion by the parasites. We assessed the inhibitory effects of 46 candidate compounds from molecular docking of CpCDPK3 on both C. parvum development and CpCDPK3 enzyme activities. One compound was identified to be effective. Results of these analyses suggest that CpCDPK3 might play an important role in the growth of C. parvum.
Highlights
Cryptosporidium spp. are apicomplexan parasites, causing moderate-to-severe diarrhea in both humans and animals worldwide (Kotloff et al, 2013; Checkley et al, 2015)
The recombinant CpCDPK3 protein was used in the generation of polyclonal antibodies and immune sera, which were used in further analysis of the purified recombinant CpCDPK3 and native CpCDPK3 in crude protein extract of sporozoites, with the pre-immune serum being used as the control
Our results suggest that CpCDPK3 protein could play an essential role in the growth but not the invasion of C. parvum
Summary
Cryptosporidium spp. are apicomplexan parasites, causing moderate-to-severe diarrhea in both humans and animals worldwide (Kotloff et al, 2013; Checkley et al, 2015). Calcium is involved in several critical events in the life cycle of apicomplexan parasites, including protein secretion, gliding motility, cell invasion, and egress (Billker et al, 2009). In these pathogens, Characterization of CDPK3 of Cryptosporidium calcium-dependent protein kinases (CDPKs) are the most abundant class of calcium sensors, being found in apicomplexan protozoa, ciliates, and plants, but not in fungi and vertebrates (Harper and Alice, 2005). Characterization of CDPK3 of Cryptosporidium calcium-dependent protein kinases (CDPKs) are the most abundant class of calcium sensors, being found in apicomplexan protozoa, ciliates, and plants, but not in fungi and vertebrates (Harper and Alice, 2005) As a result, they are considered attractive drug targets for cryptosporidiosis (Hui et al, 2015). Whole-genome sequencing and RNA-Seq analysis have identified 11 CDPKs in Cryptosporidium parvum (Lippuner et al, 2018)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
