INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Poisonous eggs from Pomacea snails have evolved a defensive protein that damage cell membranes with a pore-forming toxin delivered by a lectin
Autor/es:
MILESI, VERÓNICA; MATÉ, SABINA; ITUARTE, SANTIAGO; DREON, MARCOS SEBASTIÁN; HERAS, HORACIO; GIGLIO, MATÍAS LEONEL; PRIETO, EDUARDO; QIU, JIAN-WEN
Lugar:
Pacific Grove, California
Reunión:
Congreso; World Congress of Malacology; 2019
Resumen:
We found that eggs from the invasive freshwater snail Pomacea maculata have evolved a defensive strategy against predation involving a toxin, PmPV2, that triggers neurological signs in mice damage cells. PmPV2 is a dimeric pore-forming toxin combining two immune proteins: a lectin module linked to a membrane attack complex/perforin (MACPF) module. It triggers neurological signs in mice.The aim of this study was to investigate PmPV2 interaction with membranes using intestinal cells as a model of the first cells that the toxin would encounter when ingested by a predator eating these poisonous eggs.The toxin withstands digestive proteases and if ingested by mice attach to intestinal microvilli, suggesting it can withstand the harsh gastrointestinal conditions. At the cellular level, PmPV2 specifically recognize membrane cholesterol and its lectin module has preference for glycans attached to membrane proteins mostly negatively charged sugars, as revealed by a glycan array and hemagglutination assays. Though Atomic Force Microscopy (AFM) we observed that PmPV2 inserts into phosphoplipid/cholesterol lipid bilayers and oligomerizes into pore-like structures. Additionally, PmPV2 binds to the plasma membrane of intestinal Caco-2 cells recognizing specific glycoproteins, alters their surface morphology (AFM) and eventually leads to cell death. Intestinal cells exposed to the toxin changed their membrane permeability in Patch-clamp experiments in a fashion compatible with the formation of ~14nm pores. This effect is inhibited by aminated monosaccharides, highlighting the importance of the lectin module. The study provides the first evidence to our knowledge into the molecular mechanism of pore formation for an animal defensive toxin containing a MACPF/CDC