Mutant/mutation

The mutant expresses a C-terminal GFP-tagged version of PPKL (protein phosphatase containing kelch-like domains).

Protein (function)
PPKL is a distinctive PP1-related enzyme belonging to the PPP family of phosphatases comprising an N-terminal kelch repeat domain and a C-terminal PP1-like phosphatase domain (named PPKL: Protein Phosphatase with Kelch-Like domains). It has been detected in the apicomplexans Cryptosporidium hominis, Toxoplasma gondii and Theileria parva (one gene per genome), as well as in the land plants Arabidopsis thaliana and Oryza sativa (4 and 5 genes respectively). The kelch motif is widespread and involved in many cellular functions, particularly in actin-based cytoskeleton formation and transcriptional regulation. PPKL has only been studied in detail in Arabidopsis thaliana (where it is known as BSU1 or bri1 suppressor1) and along with the kinase BIN2, is involved in brassinosteroid hormone signalling and phosphorylation of the transcription factors BZR1 and BES1

In contrast to the human phosphatome (comprising approximately 156 phosphatases the Plasmodium genome codes for one of the smallest phosphatomes of all the eukaryotic phyla known to date, with 27 putative protein phosphatases falling into four major classes: phosphoprotein phosphatases (PPPs), metallo-dependent protein phosphatases (PPMs), protein tyrosine phosphatases (PTPs) and NLI interacting factor-like phosphatases (NIFs).

Phenotype analyses of mutants lacking expression of PPKL (RMgm-686, RMgm-687) indicate an essential role of PPKL in maturation of ookinetes.
Deletion of the ppkl gene caused abnormal ookinete development, loss of ookinete motility and failure of ookinetes to invade the mosquito midgut epithelium. Evidence is presented for aberrant formation of the apical end and disorganization of microtubules.

Phenotype
Phenotype analyses of mutants lacking expression of PPKL (RMgm-686, RMgm-687) indicate an essential role of PPKL in maturation of ookinetes.

Analyses of the mutant expressing GFP-tagged PPKLshows expression in schizonts, female gametocytes and ookinetes. Immunofluorescence studies using anti-PPKL polyclonal antibody showed expression in merozoites, female gametocytes, zygotes, ookinete, and sporozoites. Only female gametocytes and not males expressed PPKL. PPKL is localized predominantly in the cytoplasm with a particularly intense expression at the apical tip of the developing and mature ookinete.

Additional information
 

Other mutants
RMgm-785: A mutant lacking expression of PPKL
RMgm-787: An independent mutant lacking expression of PPKL
RMgm-788: An independent mutant expressing an endogenous, GFP-tagged, version of PPKL