Mutant/mutation
The mutant expresses a mutated form of CDPK4, CDPK4^G2A (and is drug-selectable marker free). In the mutated form the myristoylated glycine 2 was replaced by an alanine residue preventing myristoylation of CDPK4. In addition, the mutated CDPK4 is C-terminal tagged with 2xmyc

Protein (function)
CDPK4 belongs to an expanded family of Ca²⁺ dependent protein kinases (CDPKs). CDPKs combine an amino-terminal serine/threonine kinase domain and a carboxy-terminal calmodulin-like domain, composed of four EF hands, in the same molecule. In plants, CDPKs translate Ca²⁺ signals generated by external stimuli into cellular responses, thereby regulating cell division and differentiation, the development of tolerance to stress stimuli and the specific defense responses to pathogens.

CDPK4 plays a role in male gamete formation after activation of male gametes. It plays a role in male gametocytes axoneme formation, formation of mitotic spindles and DNA synthesis. Evidence has been presented for an additional role in sporozoites: reduced invasion of hepatocytes (RMgm-1510).  See PF3D7_0717500 for other CDPK4 mutants

Phenotype
CDPK4 plays a role in male gamete formation after activation of male gametes. No exflagellation occurs in male gametocytes lacking expression of CDPK4.

The mutant expressing the mutated CDPK4^G2A form showed the following phenotype:
No exflagellation (male gamete formation). Reduced DNA replication during male gamete formation (mainly blocked at 1N). Normal mitotoic spindle formation in microgametocytes at 10 min. after activation. Strongly reduced axoneme formation in microgametocytes at 10 min. after activation.

CDPK4 has previously been shown to be myristoylated in P. falciparum. In the mutated form the myristoylated glycine 2 was replaced by an alanine residue preventing myristoylation of CDPK4.

Additional information
 

Other mutants
See PF3D7_0717500 for other CDPK4 mutants