During the development in the mosquito midgut, plays a role in sporozoite egress from oocysts. In the mosquito vector, expressed at the ookinete stage. In the mosquito midgut, number of oocysts is normal (PubMed:18761621). However, oocyst appears immature, enlarged, degenerated or vacuolated, and fails to sporulate resulting in a lack of sporozoites (PubMed:18761621). Belongs to the peptidase A1 family. It is unclear if PMVI is glycosylated as other members of the same enzyme family, i.e. PMI and PMII, are not.