RT Journal Article T1 Synergistic action of actinoporin isoforms from the same sea anemone species assembled into functionally active heteropores A1 Rivera de Torre, Esperanza A1 García Linares, Sara A1 Alegre Cebollada, Jorge A1 Lacadena, Javier A1 Gavilanes, José G. A1 Martínez del Pozo, Álvaro AB Among the toxic polypeptides secreted in the venom of sea anemones, actinoporins are pore forming toxins whose toxic activity relies on the formation of oligomeric pores within biological membranes. Intriguingly, actinoporins appear as multigene families which give rise to many protein isoforms in the same individual displaying high sequence identities but large functional differences. However, the evolutionary advantage of producing such similar isotoxins is not fully understood. Here, using sticholysins I and II (StnI and StnII) from the sea anemone Stichodactyla helianthus, it is shown that actinoporin isoforms can potentiate each other’s activity. Through hemolysis and calcein releasing assays, it is revealed that mixtures of StnI and StnII are more lytic than equivalent preparations of the corresponding isolated isoforms. It is then proposed that this synergy is due to the assembly of heteropores since (i) StnI and StnII can be chemically cross-linked at the membrane and (ii) the affinity of sticholysin mixtures for the membrane is increased with respect to any of them acting in isolation, as revealed by isothermal titration calorimetry experiments. These results help to understand the multigene nature of actinoporins and may be extended to other families of toxins that require oligomerization to exert toxicity. PB American Society for Biochemistry and Molecular Biology SN 0021-9258, ESSN: 1083-351X YR 2016 FD 2016-04-27 LK https://hdl.handle.net/20.500.14352/24452 UL https://hdl.handle.net/20.500.14352/24452 LA eng NO Ministerio de Ciencia e Innovación (MICINN) NO UCM collaboration fellowship to ERT NO Ramón y Cajal Award DS Docta Complutense RD 28 abr 2024