During the development in the mosquito vector, plays an essential role in sporozoite egress from the oocyst and sporozoite gliding motility, which is required for the invasion of salivary glands and subsequent transmission to the host. Highly expressed at day 4 post-infection of the mosquito midgut followed by a reduction at day 8 post-infection and in midgut sporozoites (PubMed:28192122). Expression is low in salivary gland sporozoites (PubMed:28192122). Not expressed during the host liver stage (PubMed:28192122). In the mosquito vector, midgut infection and oocyst development are normal; however, sporozoites fail to egress from oocysts and their gliding motility is impaired resulting in a failure to invade the salivary glands (PubMed:28192122). Processing of circumsporozoite protein CSP on the oocyst inner surface is normal (PubMed:28192122). In the mouse host, sporozoite invasion of the liver is impaired but the growth and development of asexual blood stages are normal (PubMed:28192122). Belongs to the peptidase A1 family. It is unclear if PMVIII is glycosylated as other members of the same enzyme family, i.e. PMI and PMII, are not.