Mutant/mutation
The mutant lacks expression of SPECT2/PPLP1 (Membrane Attack Complex; MAC/perforin, putative; Plasmodium perforin like protein 1, PPLP1;  sporozoite protein essential for cell traversal, SPECT2)

Protein (function)
The spect2/pplp1 gene is a member of a small, conserved family of proteins encoding perforin-like proteins containing membrane-attack complex/perforin domains (MACPF)(Kaiser, K et al., 2004, Mol. Biochem. Parasitol. 133, 15-26). SPECT2/PPLP1 is specifically expressed in salivary gland sporozoites (not in midgut sporozoites) and has a micronemal location (micronemes).

Phenotype
The phenotype analyses indicate a rol of SPECT2/PPLP1 in traversal of the sporozoites through cells of the host. HepG2 traversal and not invasion was inhibited in the mutant sporozoites. Mutant sporozoites had restored liver infectivity in Kupffer cell-depleted rats. These results suggest that SPECT2/PPLP1 is necessary for breaching the sinusoidal cell layer via the Kupffer cells prior to hepatocyte infection (see also 'Additional information').

Additional information
Analysis of sporozoites lacking SPECT2/PPLP1 indicates a role of traversal through host cells in the dermis (for freely moving until endothelial barriers are reached and for resisting attacks by phagocytic cells) and in the liver sinusoids, presumably for resisting destruction by Kupffer cells (R. Amino et al., 2008, Cell Host & Microbe, 3, 88-96).

Other mutants
Mutants that lack expression of other members of the PPLP protein family:
RMgm-137: Another mutant lacking expression of SPECT2/PPLP1
RMgm-123: A mutant lacking expression of PPLP5
RMgm-134: A mutant lacking expression of PPLP3/MAOP
See also RMgm-92 for an unsuccessful attempt to disrupt PPLP4

See also RMgm-138 and RMgm-139 for mutants lacking the expression of SPECT which show a comparable defect in cel traversal capacity, whereas the capabilty to invade hepatocytes is not affected.