SNAP-25 

Synaptosomal-associated protein, 25kDa
PDB rendering based on 1jth.
Available structures: 1jth, 1kil, 1n7s, 1sfc, 1urq, 1xtg
Identifiers
Symbols SNAP25; FLJ23079; RIC-4; RIC4; SEC9; SNAP; SNAP-25; bA416N4.2; dJ1068F16.2
External IDs OMIM: 600322 MGI98331 HomoloGene13311
RNA expression pattern

More reference expression data

Orthologs
Human Mouse
Entrez 6616 20614
Ensembl ENSG00000132639 ENSMUSG00000027273
Uniprot P60880 P60879
Refseq NM_003081 (mRNA)
NP_003072 (protein)
NM_011428 (mRNA)
NP_035558 (protein)
Location Chr 20: 10.15 - 10.24 Mb Chr 2: 136.4 - 136.47 Mb
Pubmed search [1] [2]

SNAP-25 (synaptosome-associated protein of 25,000 daltons) is a membrane bound protein anchored to the cytosolic face of membranes via palmitoyl side chains in the middle of the molecule. SNAP-25 is a Q-SNARE protein contributing two α-helices in the formation of the exocytotic fusion complex in neurons where it assembles with syntaxin-1 and synaptobrevin. SNAP-25 inhibits P/Q- and L-type voltage-gated calcium channels located presynaptically 1 and interacts with the synaptotagmin C2B domain in Ca2+-independent fashion 2. In glutamatergic synapses SNAP-25 decreases the Ca2+ responsiveness, while it is naturally absent in GABAergic synapses 3.

Consistent with the regulation of synaptic Ca2+ responsiveness, heterozygous deletion of the SNAP-25 gene in mice results in a hyperactive phenotype similar to attention deficit hyperactivity disorder (ADHD). In heterozygous mice, a decrease in hyperactivity is observed with dextroamphetamine (or Dexedrine), an active ingredient in the ADHD drug Adderall. Homozygous deletions of the SNAP-25 gene are lethal. Subsequent studies have suggested that at least some of the SNAP-25 gene mutations in humans might predispose to ADHD 45.

Botulinum toxins A, C and E cleave SNAP-25 6 leading to paralysis in clinically developed botulism.

Molecular machinery driving exocytosis in neuromediator release. The core SNARE complex is formed by four α-helices contributed by synaptobrevin, syntaxin and SNAP-25, synaptotagmin serves as a Ca2+ sensor and regulates intimately the SNARE zipping.


References

  1. ^ Hodel A (1998). "SNAP-25". The International Journal of Biochemistry & Cell Biology 30 (10): 1069–1073. doi:10.1016/S1357-2725(98)00079-X. 
  2. ^ Chapman ER (2002). "Synaptotagmin: A Ca2+ sensor that triggers exocytosis?". Nature Reviews Molecular Cell Biology 3: 498–508. 
  3. ^ Pozzi D, Verderio C, Patti L, Grumelli C, Inverardi F, Frassoni C, Bonanno G, Matteoli M (2004). "SNAP-25 modulation of calcium dynamics underlies differences in GABAergic and glutamatergic responsiveness to depolarization". Neuron 41 (4): 599–610. doi:10.1016/S0896-6273(04)00077-7. 
  4. ^ Brophy K, Hawi Z, Kirley A, Fitzgerald M, Gill M (2002). "Synaptosomal-associated protein 25 (SNAP-25) and attention deficit hyperactivity disorder (ADHD): evidence of linkage and association in the Irish population". Molecular Psychiatry 7 (8): 913–917. doi:10.1038/sj.mp.4001092. 
  5. ^ Mill J, Curran S, Kent L, Gould A, Huckett L, Richards S, Taylor E, Asherson P (2002). "Association study of a SNAP-25 microsatellite and attention deficit hyperactivity disorder". American Journal of Medical Genetics 114 (3): 269–271. doi:10.1002/ajmg.10253. 
  6. ^ Aoki KR, Guyer B (2001). "Botulinum toxin type A and other botulinum toxin serotypes: a comparative review of biochemical and pharmacological actions". European Journal of Neurology 8: 21–29. doi:10.1046/j.1468-1331.2001.00035.x. 

Further reading

External links