title: High affinity binding of alpha-latrotoxin to recombinant neurexin I alpha.
abstract: alpha-Latrotoxin is a potent neurotoxin from black widow spider venom that stimulates neurotransmitter release. alpha-Latrotoxin is thought to act by binding to a high affinity receptor on presynaptic nerve terminals. In previous studies, high affinity alpha-latrotoxin binding proteins were isolated and demonstrated to contain neurexin I alpha as a major component. Neurexin I alpha is a cell surface protein that exists in multiple differentially spliced isoforms and belongs to a large family of neuron-specific proteins. Using a series of neurexin I-IgG fusion proteins, we now show that recombinant neurexin I alpha binds alpha-latrotoxin directly with high affinity (Kd approximately 4 nM). Binding of alpha-latrotoxin to recombinant neurexin I alpha is dependent on Ca2+ (EC50 approximately 30 microM). Our data suggest that neurexin I alpha is a Ca(2+)-dependent high affinity receptor for alpha-latrotoxin.
authors.affiliation: Department of Molecular Genetics, University of Texas Southwestern Medical School, Dallas 75235, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Davletov
authors.forename: V
authors.initials: V
authors.lastname: Krasnoperov
authors.forename: Y
authors.initials: Y
authors.lastname: Hata
authors.forename: A G
authors.initials: AG
authors.lastname: Petrenko
authors.forename: T C
authors.initials: TC
authors.lastname: Südhof
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D002522:Chlorocebus aethiops; D006023:Glycoproteins; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D009479:Neuropeptides; D009498:Neurotoxins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013111:Spider Venoms / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection
chemical_list: D006023:Glycoproteins; D007074:Immunoglobulin G; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D009498:Neurotoxins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D013111:Spider Venoms; C112162:neurexophilin; C020763:alpha-latrotoxin; D002118:Calcium