Serine protease involved in intramembrane proteolysis and the subsequent release of polypeptides from their membrane anchors. Has no detectable activity towards MIC2. Cleaves type-1 transmembrane domains using a catalytic dyad composed of serine and histidine that are contributed by different transmembrane domains. Detected in micronemes in intracellular and extracellular tachyzoites, together with MIC2. Detected in tachyzoites, bradyzoites and sporozoites. Belongs to the peptidase S54 family.