Characterization of CpCaM, a protein potentially involved in the growth of Cryptosporidium parvum

Cryptosporidium parvum is an important apicomplexan parasite causing severe diarrhea in both humans and animals. Calmodulin (CaM), a multifunctional and universal calcium-binding protein, contributes to the growth and development of apicomplexan parasites, but the role of CaM in C. parvum remains unknown. In this study, the CaM of C. parvum encoded by the cgd2_810 gene was expressed in Escherichia coli, and the biological functions of CpCaM were preliminarily investigated. The transcriptional level of the cgd2_810 gene peaked at 36 h post infection (pi), and the CpCaM protein was mainly located around the nucleus of the whole oocysts, in the middle of sporozoites and around the nucleus of merozoites. Anti-CpCaM antibody reduced the invasion of C. parvum sporozoites by 30.69%. The present study indicates that CpCaM is potentially involved in the growth of C. parvum. Results of the study expand our knowledge on the interaction between host and Cryptosporidium.