Calcium-dependent protein kinase which acts as a sensor and effector of intracellular Ca(2+) levels probably in part downstream of cGMP-activated PKG kinase (By similarity). Plays a central role in host erythrocytes and hepatocytes infection cycles (PubMed:32866196). During the liver stage, involved in sporozoite motility and thus in sporozoite invasion of host hepatocytes, probably together with CDPK1 and CDPK4 (PubMed:32866196). Involved in merosome egress from host hepatocytes, probably together with CDPK4 (PubMed:32866196). Required for the release of hepatic merozoites from merosomes in the host blood stream (PubMed:32866196). During the asexual blood stage, required for merozoite egress from host erythrocytes by triggering microneme secretion (By similarity). Phosphorylates transporter NPT1 at late schizont stage (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by calcium (By similarity). Upon calcium binding to the EF-hand domains, the C-terminus of the junction domain (J domain) undergoes a conformational change which results in the dissociation of the pseudo-substrate inhibitory motif from the catalytic domain (By similarity). This, in turn, may facilitate the autophosphorylation of the activation loop at Thr-278, which leads to the kinase activation (By similarity). During the late stages of schizogony, localizes to the cytoplasm in immature daughter merozoites, co-localizes with AMA1 to a subset of micronemes and to the apical region in maturing daughter merozoites, and near the plasma membrane in mature daughter and free merozoites. Expressed in sporozoites and in the late mature liver stage (at protein level) (PubMed:32866196). Expressed in the merosome, a membrane-surrounded vesicle which contains mature merozoites and produced at the end of the liver stage (at protein level) (PubMed:32866196). The junction domain (J domain) is composed of 2 motifs that maintain the kinase inactive. The N-terminal autoinhibitory motif acts as a pseudosubstrate inhibiting the catalytic domain while the C-terminal motif binds the EF-hand domains. May be palmitoylated. Autophosphorylated in vitro. Sporozoite attachment to the substrate is normal but sporozoite uninterrupted circular movement is impaired (PubMed:32866196). No effect on cell traversal but reduces invasion of host hepatocytes (PubMed:32866196). Reduces merosome release from infected host hepatocytes (PubMed:32866196). Infection of mice with knockout merosomes causes a severe delay in host erythrocytes infection without affecting the asexual replication in host erythrocytes (PubMed:32866196). Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. CDPK subfamily.