Intramembrane proteolysis of Toxoplasma apical membrane antigen 1 facilitates host-cell invasion but is dispensable for replication.

ABSTRACT: Apical membrane antigen 1 (AMA1) is a conserved transmembrane adhesin of apicomplexan parasites that plays an important role in host-cell invasion. Toxoplasma gondii AMA1 (TgAMA1) is secreted onto the parasite surface and subsequently released by proteolytic cleavage within its transmembrane domain. To elucidate the function of TgAMA1 intramembrane proteolysis, we used a heterologous cleavage assay to characterize the determinants within the TgAMA1 transmembrane domain (ALIAGLAVGGVLLLALLGGGCYFA) that govern its processing. Quantitative analysis revealed that the TgAMA1(L/G) mutation enhanced cleavage by 13-fold compared with wild type. In contrast, the TgAMA1(AG/FF) mutation reduced cleavage by 30-fold, whereas the TgAMA1(GG/FF) mutation had a minor effect on proteolysis; mutating both mot

SUBMITTER: Parussini F 

PROVIDER: S-EPMC3358886 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature