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α‐Latrotoxin forms calcium‐permeable membrane pores via interactions with latrophilin or neurexin
Author(s) -
Van Renterghem Catherine,
Iborra Cécile,
MartinMoutot Nicole,
Lelianova Vera,
Ushkaryov Yuri,
Seagar Michael
Publication year - 2000
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2000.00282.x
Subject(s) - neurexin , calcium , membrane , chemistry , biophysics , biochemistry , biology , organic chemistry , receptor , postsynaptic potential
In order to explore the mechanisms by which α‐latrotoxin activates neurotransmitter release, we have characterized its effects by patch‐clamp methods on cells heterologously expressing its receptors, latrophilin‐1 or neurexin‐Iα. Application of α‐latrotoxin (1 n m ) to cells expressing rat latrophilin or neurexin, but not mock‐transfected cells, induced a cationic conductance. In cells expressing latrophilin, current development was slow in the absence of divalent cations, but was accelerated by Ca 2+ or Mg 2+ . In cells expressing neurexin, α‐latrotoxin did not elicit currents in the absence of Ca 2+ . The toxin‐induced conductance was rectifying, persistent, permeable to monovalent and divalent cations, but blocked by La 3+ . Single‐channel recording revealed a permanently open state, with the same unitary conductance irrespective of whether cells expressed latrophilin or neurexin. Therefore, while pore formation displayed differences consistent with the reported properties of α‐latrotoxin binding to latrophilin and neurexin, the pores induced by α‐latrotoxin had identical properties. These results suggest that after anchoring to either of its nerve terminal receptors, α‐latrotoxin inserts into the membrane and constitutes a single type of transmembrane ion pore.