1.C.39.2.9
Two component cytolysin, perivitellin-2, one subunit (P0C8G6) is a 67 KDa subunit, and the other (P0DQP0) is a 31 kDa (286 aas) subunit. The egg defensive protein, perivitellin-2, is thus a pore-forming two-subunit glycoprotein that affects both the nervous and digestive systems of mammals (Heras et al. 2008). It is a source of both structural and energetic molecules during embryonic development. The tachylectin subunit (31 kDa) binds target membranes while the MACPF subunit (67 kDa) disrupts lipid bilayers forming large pores altering the plasma membrance conductance (Dreon et al. 2013).  The perivitellin-2 (PV2) from snails is an unusual neuro and enterotoxin comprising a pore-forming domain of the Membrane Attack Complex and Perforin Family (MACPF) linked to a lectin. Both domains have membrane binding capabilities. The apple snail Pomacea maculata PV2's (PmPV2's) interaction with lipid membranes was studied (Vázquez et al. 2025). PmPV2 toxicity decreased when cholesterol (Chol) was diminished from enterocyte cell membranes. Chol enhanced PmPV2 association with phosphatidylcholine membranes but did not induce pore formation. In contrast, using rat brain lipid models, rich in glycolipids, PmPV2 exhibited high affinity and induced vesicle permeabilization. Negative stain electron microscopy and atomic force microscopy confirmed the formation of pore-like structures in brain lipid vesicles. Thus, Chol is a necessary lipid component, but PmPV2-glycolipid interactions are potential activators critical to triggering PmPV2's pore-forming activity (Vázquez et al. 2025).