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). In the mosquito midgut, regulates the gliding motility of the ookinete which is essential for the ookinete to invade the midgut epithelium (PubMed:16796674). However, another study showed that while required for ookinete invasion of the midgut epithelium, is not required for ookinete gliding motility (PubMed:16430692). 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 domain 2, 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-271, which leads to the kinase activation (By similarity). Expressed in ookinetes; expression increases during ookinete maturation (at protein level). The EF-hand domain 1 cannot bind calcium due to the presence of a Lys instead of an Asp at position 427 and a Gln instead of a Glu at position 434 preventing calcium binding (By similarity). The EF-hand domains 3 and 4 probably bind calcium constitutively when calcium levels are low, while the EF-hand domain 2 binds calcium following an increase in calcium levels (By similarity). 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. In the mosquito midgut, the number of oocysts are reduced which is caused by a failure of ookinetes to migrate to and transverse midgut epithelium (PubMed:16430692, PubMed:16796674). Abnormal motility of ookinetes, characterized by frequent flexing, bending, twirling, pendular motions and a failure to disperse (PubMed:16796674). However, another study shows no defect in ookinete motility (PubMed:16430692). Development and morphology of ookinetes are normal (PubMed:16430692, PubMed:16796674). Sporozoite motility and infectivity are normal (PubMed:16430692, PubMed:16796674). When injected directly into the mosquito haemocoel, thus bypassing the requirement to transverse the midgut epithelium, ookinetes mature normally into oocysts (PubMed:16796674). Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. CDPK subfamily.