Mutant/mutation
The mutant lacks expression of TLP (Trap-Like Protein; TRAP2).

Protein (function)
TLP belongs to the TRAP/MIC2 family of transmembrane proteins, members of which link extracellular adhesion to the intracellular actomyosin motor complex that plays a role in (gliding) motility and cell invasion.
Similar to the Plasmodium sporozoite protein, TRAP, and the ookinete protein, CTRP, TLP possesses an extracellular domain architecture that is comprised of von Willebrand factor A (vWA) and thrombospondin type 1 (TSP1) domains, plus a short cytoplasmic domain.

Phenotype
The phenotype analyses indicate that TLP has no essential role during the life cycle and is not involved in gliding motility of sporozoites and invasion of hepatocytes.   
An independent mutant RMgm-143 has been generated which lacks expression of TLP. Phenotype analyses of this mutant indicate a role of TLP in cell traversal of the sporozoite stage. However, the lack of a 'clear' phenotype indicates redundancy of the function of TLP. See also the paper of Lacroix and Menard ( 2008, Trends Parasitol, 24, 431-34) for a comparison of the phenotype of both mutants.

Additional information
Transcription of tlp have been detected by RT-PCR in blood stages and sporozoites.

A mutant has been generated (RMgm-149) that expresses a mutated form of TRAP (thrombospondin-related anonymous protein; PB000374.03.0; PF13_0201), in which the cytoplasmic tail domain (CTD) of TRAP is replaced with the CTD domain of TLP. The CTD of TLP can complement the function of the CTD of TRAP, albeit not as well as TRAP as shown by the (strongly) reduced invasion of salivary glands and hepatocytes.

Adhesion and motility of sporozoites of this mutant has been analysed in another study (Hegge et al., 2010, FASEB J; PMID: 20159960). Analyses of gliding and adhesion properties on glass slide indicate that 'TLP appears to increase the probability of continued adhesion formation during gliding, either by stabilization of newly formed adhesion sites or by increasing the speed of adhesion formation'. It is suggested that in migrating through tissue, the loss of TLP function could therefore result in reduced attachment and thus slower progression through tissues.

Other mutants
RMgm-143: An independant mutant lacking expression of TLP.
RMgm-149:  A mutant that expresses a mutated form of TRAP (thrombospondin-related anonymous protein; PB000374.03.0; PF13_0201), in which the cytoplasmic tail domain (CTD) of TRAP is replaced with the CTD domain of TLP.