Trachynilysin, a toxin isolated from stonefish Synanceia trachynis venom, forms pores in planar lipid bilayers.

Trachynilysin (TLY), a 159-kDa protein isolated from stonefish (Synanceia t rachynis) venom, increases spontaneous quantal acetylcholine release at the frog neuromuscular junction in a Ca2+ dependent manner and depletes clear vesicles without affecting large dense-core vesicles (Colasante et al., 199 6). TLY induces a catecholamine release from bovine adrenal chromaffin cell s via external and stored Ca2+. This release is not affected by voltage-gat ed Ca2+ channel inhibitors (Meunier et al., 2000). We show in this study th at TLY is able to form pores in planar lipid bilayers. These pores have a m aximum conductance of about 90 pS (NaCl 150 mM cis / KCI 150 mM trans) and are blocked by Ni2+. Thus, TLY, like alpha -latrotoxin, might act by formin g pores in natural membranes.