Recombinant Plasmodium falciparum Calcium-dependent protein kinase 1 (CPK1), partial

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 phosphorylating various proteins, required for microneme secretion and thus merozoite egress from and invasion of host erythrocytes. During gametogenesis, essential for the development of both male and female gametes. Phosphorylates SERA5 p50 which enhances SERA5 p50 protease activity; however, SERA5 p50 protease activity has been shown in other studies to be controversial. Probably by phosphorylating SERA5 p50, plays a role in merozoite egress from host erythrocytes. Probably prior or during merozoite invasion of host erythrocytes, phosphorylates rhoptry protein RhopH3 which is required for RhopH3 localization to rhoptries and for its secretion. Probably in late schizonts, phosphorylates myosin A tail domain-interacting protein MTIP and glideosome-associated protein 45 GAP45, both of which are components of the motor complex that generates the force required by the parasite to invade host cells. In late schizonts, phosphorylates inner membrane complex protein IMC1g. In late schizonts, phosphorylates PKA regulatory subunit PKAr in a calcium-dependent manner, which may contribute to the dissociation of regulatory PKAr and catalytic PKAc subunits and promote the activation of PKAc. May phosphorylate raf kinase inhibitory protein RKIP which in turn may regulate CDPK1 catalytic activity. May phosphorylate proteins of the host erythrocyte membranes.