Mutant/mutation
The mutant expressses a C-terminal HA-tagged version of PIP5K

Protein (function)
Enzymes in the inositol phospholipid biosynthetic pathway. Phosphorylated phosphatidylinositol lipids have important roles in vesicle trafficking and as a source of secondary messengers in signal transduction. Their biosynthesis from phosphatidyl-1D-myo-inositol (PI) is mediated by lipid kinases. The P. berghei genome encodes four putative lipid kinases to convert PI first to phosphatidylinositol 4-phosphate (PI4P) and then to phosphatidylinositol (4,5)- bisphosphate (PI(4,5)P2). Hydrolysis of the latter by a PI-specific phospholipase C (PI-PLC) gives rise to the secondary messenger inositol (1,4,5)-trisphosphate (IP3), which plays an important role in P. berghei gametocytes, where it is responsible for the mobilisation of Ca2+ from internal stores, leading to activation and gametogenesis.

To test whether the PKG-dependent phosphorylation of enzymes associated with phosphoinositide metabolism has a direct role in ookinete motility, an experimental genetics approach was used to infer the role of putative PI kinases. Both the putative PI4K (PBANKA_110940) and the putative PIP5K (PBANKA_020310) were unable to be genetically disrupted (unpublished data), suggesting these genes may be essential for asexual growth, although both loci could be modified.

Phenotype
Expression of PIP5K-HA in ookinetes

Additional information
The location of PIP5K-HA rapidly redistributed from the cell periphery to the ookinete cytosol in ookinetes when treated with 0.5 mM C2 (an inhibitor of PKG), supporting a direct link between PKG and phosphoinositide metabolism.

Other mutants
RMgm-997: Unsuccessful attempts to disrupt PIP5K
RMgm-996: Unsuccessful attempts to disrupt PI4K (PBANKA_110940)
RMgm-969: A mutant expressing a mutated form of PI4K (PBANKA_110940)