Trachynilysin, a neurosecretory protein isolated from stonefish (Synanceia trachynis) venom, forms nonselective pores in the membrane of NG108-15 cells.
Trachynilysin, a protein toxin isolated from the venom of the stonefish Synanceia trachynis, has been reported to elicit massive acetylcholine release from motor nerve endings of isolated neuromuscular preparations and to increase both cytosolic Ca2+ and catecholamine release from chromaffin cells. In the present study, we used the patch clamp technique to investigate the effect of trachynilysin on the cytoplasmic membrane of differentiated NG108-15 cells in culture. Trachynilysin increased membrane conductance the most when the negativity of the cell holding membrane potential was reduced. The trachynilysin-induced current was carried by cations and reversed at about -3 mV in standard physiological solutions, which led to strong membrane depolarization and Ca2+ influx. La3+ blocked the trachynilysin current in a dose-, voltage-, and time-dependent manner, and antibodies raised against the toxin antagonized its effect on the cell membrane. The inside-out configuration of the patch clamp technique allowed the recording of single channel activity from which various multiples of 22 pS elementary conductance were resolved. These results indicate that trachynilysin forms pores in the NG108-15 cell membrane, and they advance our understanding of the toxin's mode of action on motor nerve endings and neurosecretory cells.
Ouanounou
Gilles
G
Laboratoire de Neurobiologie Cellulaire et Moléculaire, UPR 9040 CNRS, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.
Malo
Michel
M
Stinnakre
Jacques
J
Kreger
Arnold S
AS
Molgo
Jordi
J
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005397:Fish Venoms / Q000737:chemistry* / Q000378:metabolism*; D005400:Fishes, Poisonous; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007477:Ions; D007811:Lanthanum / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D009498:Neurotoxins / Q000737:chemistry*; D018408:Patch-Clamp Techniques; D013997:Time Factors; D014407:Tumor Cells, Cultured
D002395:Catecholamines; D005397:Fish Venoms; D007074:Immunoglobulin G; D007477:Ions; D009498:Neurotoxins; C103845:trachynilysin; D007811:Lanthanum; D000109:Acetylcholine; D002118:Calcium