These results, indicating that <i>O</i>-fucosylation of TSRs is required for efficient processing of MIC2 and for normal parasite invasion, are consistent with the recent demonstration that <i>Plasmodium falciparum</i> Δ<i>pofut2</i> strain has decreased virulence and also support a conserved role for this glycosylation pathway in quality control of TSR-containing proteins in eukaryotes.
When expressed in a mammalian cell line deficient in C-mannosylation, P. falciparum and T. gondii Dpy19 homologs were able to modify TSR domains of the micronemal adhesins TRAP/MIC2 family involved in parasite motility and invasion.
These integrated CD99 gene and protein expression results suggest that CD99 expression in astrocytomas of different malignant grades might contribute to the infiltrative ability and support the importance of CD99 as a potential target to reduce infiltrative astrocytoma capacity in migration and invasion.
Despite the importance of ROM4 for efficient invasion, mutants lacking all three ROMs were viable and MIC2 was still efficiently removed from the surface of invaded mutant parasites, implying the existence of ROM-independent mechanisms for adhesin removal during invasion.
Reduced MIC2 expression resulted in mistrafficking of M2AP, markedly defective host-cell attachment and invasion, the loss of helical gliding motility, and the inability to support lethal infection in a murine model of acute toxoplasmosis.