Ostreolysin A/Pleurotolysin B and Equinatoxins: Structure, Function and Pathophysiological Effects of These Pore-Forming Proteins

Abstract

Acidic ostreolysin A/pleurotolysin B (OlyA/PlyB, formerly known as ostreolysin (Oly), and basic 20 kDa equinatoxins (EqTs) are cytolytic proteins isolated from the edible mushroom Pleurotus ostreatus and the sea anemone Actinia equina, respectively. Both toxins, although from different sources, share many similar biological activities: (i) colloid-osmotic shock by forming pores in cellular and artificial membranes enriched in cholesterol and sphingomyelin; (ii) increased vascular endothelial wall permeability in vivo and perivascular oedema; (iii) dose-dependent contraction of coronary vessels; (iv) haemolysis with pronounced hyperkalaemia in vivo; (v) bradycardia, myocardial ischemia and ventricular extrasystoles accompanied by progressive fall of arterial blood pressure and respiratory arrest in rodents. Both types of toxins are haemolytic within nanomolar range concentrations, and it seems that hyperkalaemia plays an important role in toxin cardiotoxicity. However, it was observed that the haemolytically more active EqT III is less toxic than EqT I, the most toxic and least haemolytic EqT. In mice, EqT II is more than 30 times more toxic than OlyA/PlyB when applied intravenously. These observations imply that haemolysis with hyperkalaemia is not the sole cause of the lethal activity of both toxins. Additional mechanisms responsible for lethal action of the two toxins are direct effects on heart, coronary vasoconstriction and related myocardial hypoxia. In this review, we appraise the pathophysiological mechanisms related to the chemical structure of OlyA/PlyB and EqTs, as well as their toxicity.

Proteome Analysis and In Vitro Antiviral, Anticancer and Antioxidant Capacities of the Aqueous Extracts of Lentinula edodes and Pleurotus ostreatus Edible Mushrooms

“…Our data show the expression of both ostreolysin and pleurotolysin in Pleurotus ostreatus. These are pore-forming proteins with highly selective anticancer activities [ 44 , 45 ]. Ostreolysin is a 15 kDa cytolytic protein with the ability to permeabilize erythrocytes and other cells at sub-micromolar concentrations.…”

Herramientas biológicas

“…lilacinum, no produce estructuras mecánicas que le permitan atrapar nematodos, sin embargo, produce una potente toxina que los inmoviliza (Frangež et al, 2017) para luego digerirlos (Barron, 1992). En investigaciones donde se extrajo la toxina del micelio para ser aplicada in vitro sobre formas móviles de los nematodos, se reportaron efectos como constricciones de cuello y cabeza (Satou et al, 2008) inmovilidad y mortalidad (Heydari et al, 2006).…”