VAMP/synaptobrevin cleavage by tetanus and botulinum neurotoxins is strongly enhanced by acidic liposomes.
Tetanus and botulinum neurotoxins (TeNT and BoNTs) block neuroexocytosis via specific cleavage and inactivation of SNARE proteins. Such activity is exerted by the N-terminal 50 kDa light chain (L) domain, which is a zinc-dependent endopeptidase. TeNT, BoNT/B, /D, /F and /G cleave vesicle associated membrane protein (VAMP), a protein of the neurotransmitter-containing small synaptic vesicles, at different single peptide bonds. Since the proteolytic activity of these metalloproteases is higher on native VAMP inserted in synaptic vesicles than on recombinant VAMP, we have investigated the influence of liposomes of different lipid composition on this activity. We found that the rate of VAMP cleavage with all neurotoxins tested here is strongly enhanced by negatively charged lipid mixtures. This effect is at least partially due to the binding of the metalloprotease to the lipid membranes, with electrostatic interactions playing an important role.
Caccin
Paola
P
Istituto di Neuroscienze del CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, Via G. Colombo 3, 35121 Padova, Italy.
Rossetto
Ornella
O
Rigoni
Michela
M
Johnson
Eric
E
Schiavo
Giampietro
G
Montecucco
Cesare
C
D001905:Botulinum Toxins / Q000378:metabolism*; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000378:metabolism*; D050683:R-SNARE Proteins; D055672:Static Electricity; D013744:Tetanus Toxin / Q000378:metabolism*
D008081:Liposomes; D008565:Membrane Proteins; D050683:R-SNARE Proteins; D013744:Tetanus Toxin; D008666:Metalloendopeptidases; D001905:Botulinum Toxins