Mutant/mutation
The mutant expresses C-terminal 3xHA-tagged GPR180

Protein (function)
Heptahelical serpentine receptors are the largest group of membrane receptors responsible for transducing extracellular signals to various downstream effectors. The serpentine receptors coupled to heterotrimeric guanine nucleotide-binding proteins belong to G-protein-coupled receptors (GPCRs) with a salient feature of seven transmembrane domains, each consisting of 25–35 residues. Although there is little conservation in amino acid (aa) sequences across the entire GPCR superfamily, they share similar structures, which are used to classify the GPCRs into six main classes (A – F). Rhodopsin-like Class A is the largest class, accounting for around 90% of GPCRs. Structurally, Rhodopsin-like GPCRs have a GpcrRhopsn4 domain, an eighth helix, and a palmitoylated cysteine at the C-terminal tail. Bioinformatic analysis identified a gpr180-like gene in all Plasmodium species, with the GPCR-like transmembrane domain located in the C terminus, as predicted using the HMMER program. The ~250 aa GPCR domain contains residues that are highly conserved in the Rhodopsin-like GPCR transmembrane domain, which classifies the GPR180 proteins as Class A (Rhodopsin-like) family members of GPCRs

Phenotype
Expression of GPR180 in schizonts, gametocytes and ookinetes with highest expression in gametocytes. Evidence is presented that gametocyte activation stimulates GPR180 redistribution from the cytoplasm to the plasma membrane.

In schizonts, male and female gametocytes, the PbGPR180 fluorescence displayed diffused and occasionally punctate staining in the cytoplasm of the parasites. However, more PbGPR180 fluorescence was associated with the plasma membrane in female gametes, whereas it was mainly detected at the residual body of exflagellating male gametocytes. In both zygote and ookinete, PbGPR180 protein was predominantly associated with the plasma membrane. Furthermore, it was detected in ookinetes under both permeabilizing and nonpermeabilizing conditions, suggesting surface localization. 

Analysis of a mutant lacking expression of GPR180 (see RMgm-5196) indicates a function during male and female gamete formation (normal (wild type) numbers of gametocytes are produced; male gamete formation ~2fold reduced (as determined by counting exflagellation); female gamete formation reduced by ~ 30%. Crossing experiments indicate a more severe defect in female gametes compared to males. Reduced ookinete formation).

Additional information

Other mutants