N-ethylmaleimide sensitive fusion protein explained

N-ethylmaleimide-sensitive factor, also known as NSF or N-ethylmaleimide sensitive fusion proteins, is an enzyme which in humans is encoded by the NSF gene.^{[1] [2] [3]}

Function

NSF is a homohexameric AAA ATPase involved in membrane fusion.^[4] NSF is ubiquitously found in the membrane of eukaryotic cells. It is a central component of the cellular machinery in the transfer of membrane vesicles from one membrane compartment to another. During this process, SNARE proteins on two joining membranes (usually a vesicle and a target membrane such as the plasma membrane) form a complex, with the α-helical domains of the SNAREs coiling around each other and forming a very stable four-helix bundle. As SNAREs intertwine, they pull the vesicle towards the target membrane, excluding water and promoting fusion of the vesicle with the target membrane. NSF unravels SNARE complexes once membrane fusion has occurred, using the hydrolysis of ATP as an energy source, allowing the dissociated SNAREs to be recycled for reuse in further rounds of membrane fusion.^[5] This proposal remains controversial, however. Recent work indicates that the ATPase function of NSF does not function in recycling of vesicles but rather functions in the act of fusing vesicles with the plasma membrane.^[6]

SNARE hypothesis

Because neuronal function depends on the release of neurotransmitters at a synapse — a process in which synaptic vesicles fuse with the presynaptic membrane — NSF is a key synaptic component. Thus, conditional temperature-sensitive mutations in the Drosophila melanogaster gene for NSF lead to a comatose behaviour at the restrictive temperature (and hence the gene is called comatose), presumably because neuronal functions are blocked. In Dictyostelium discoideum amoebae, similar mutations lead to a cessation of cell movement at the restrictive temperature, indicating a role for intracellular membrane transport in migration. Another neuronal role for NSF is indicated by its direct binding to the GluR2 subunit of AMPA type glutamate receptors (which detect the neurotransmitter glutamate). This gives NSF a putative role in delivery and expression of AMPA receptors at the synapse.^[7]

NSF was discovered by James Rothman and colleagues in 1987 while at Stanford University; they identified NSF after observing that a cytoplasmic factor, required for membrane fusions, was inactivated by treatment with N-ethylmaleimide. This assay enabled them to purify NSF.^[8]

Interactions

N-ethylmaleimide sensitive fusion protein has been shown to interact with NAPA.^{[9] [10]}

Further reading

• Wilson DW, Whiteheart SW, Wiedmann M, Brunner M, Rothman JE . A multisubunit particle implicated in membrane fusion . The Journal of Cell Biology . 117 . 3 . 531–8 . May 1992 . 1315316 . 2289450 . 10.1083/jcb.117.3.531 .
• Hanson PI, Otto H, Barton N, Jahn R . The N-ethylmaleimide-sensitive fusion protein and alpha-SNAP induce a conformational change in syntaxin . The Journal of Biological Chemistry . 270 . 28 . 16955–61 . Jul 1995 . 7622514 . 10.1074/jbc.270.28.16955 . free .
• Püschel AW, O'Connor V, Betz H . The N-ethylmaleimide-sensitive fusion protein (NSF) is preferentially expressed in the nervous system . FEBS Letters . 347 . 1 . 55–8 . Jun 1994 . 8013662 . 10.1016/0014-5793(94)00505-2 . 8148431 . free .
• Whiteheart SW, Rossnagel K, Buhrow SA, Brunner M, Jaenicke R, Rothman JE . N-ethylmaleimide-sensitive fusion protein: a trimeric ATPase whose hydrolysis of ATP is required for membrane fusion . The Journal of Cell Biology . 126 . 4 . 945–54 . Aug 1994 . 8051214 . 2120109 . 10.1083/jcb.126.4.945 .
• Nagahama M, Orci L, Ravazzola M, Amherdt M, Lacomis L, Tempst P, Rothman JE, Söllner TH . A v-SNARE implicated in intra-Golgi transport . The Journal of Cell Biology . 133 . 3 . 507–16 . May 1996 . 8636227 . 2120813 . 10.1083/jcb.133.3.507 .
• Hoyle J, Phelan JP, Bermingham N, Fisher EM . Localization of human and mouse N-ethylmaleimide-sensitive factor (NSF) gene: a two-domain member of the AAA family that is involved in membrane fusion . Mammalian Genome . 7 . 11 . 850–2 . Nov 1996 . 8875895 . 10.1007/s003359900249 . 21435412 .
• Jacobsson G, Meister B . Molecular components of the exocytotic machinery in the rat pituitary gland . Endocrinology . 137 . 12 . 5344–56 . Dec 1996 . 8940356 . 10.1210/endo.137.12.8940356 . free .
• Timmers KI, Clark AE, Omatsu-Kanbe M, Whiteheart SW, Bennett MK, Holman GD, Cushman SW . Identification of SNAP receptors in rat adipose cell membrane fractions and in SNARE complexes co-immunoprecipitated with epitope-tagged N-ethylmaleimide-sensitive fusion protein . The Biochemical Journal . 320 . 2 . 429–36 . Dec 1996 . 8973549 . 1217948 . 10.1042/bj3200429.
• Germain-Lee EL, Obie C, Valle D . NVL: a new member of the AAA family of ATPases localized to the nucleus . Genomics . 44 . 1 . 22–34 . Aug 1997 . 9286697 . 10.1006/geno.1997.4856 . free .
• Subramaniam VN, Loh E, Hong W . N-Ethylmaleimide-sensitive factor (NSF) and alpha-soluble NSF attachment proteins (SNAP) mediate dissociation of GS28-syntaxin 5 Golgi SNAP receptors (SNARE) complex . The Journal of Biological Chemistry . 272 . 41 . 25441–4 . Oct 1997 . 9325254 . 10.1074/jbc.272.41.25441 . free .
• Lowe SL, Peter F, Subramaniam VN, Wong SH, Hong W . A SNARE involved in protein transport through the Golgi apparatus . Nature . 389 . 6653 . 881–4 . Oct 1997 . 9349823 . 10.1038/39923 . 1997Natur.389..881L . 4421051 .
• Barnard RJ, Morgan A, Burgoyne RD . Stimulation of NSF ATPase activity by alpha-SNAP is required for SNARE complex disassembly and exocytosis . The Journal of Cell Biology . 139 . 4 . 875–83 . Nov 1997 . 9362506 . 2139964 . 10.1083/jcb.139.4.875 .
• Osten P, Srivastava S, Inman GJ, Vilim FS, Khatri L, Lee LM, States BA, Einheber S, Milner TA, Hanson PI, Ziff EB . The AMPA receptor GluR2 C terminus can mediate a reversible, ATP-dependent interaction with NSF and alpha- and beta-SNAPs . Neuron . 21 . 1 . 99–110 . Jul 1998 . 9697855 . 10.1016/S0896-6273(00)80518-8 . free .
• McDonald PH, Cote NL, Lin FT, Premont RT, Pitcher JA, Lefkowitz RJ . Identification of NSF as a beta-arrestin1-binding protein. Implications for beta2-adrenergic receptor regulation . The Journal of Biological Chemistry . 274 . 16 . 10677–80 . Apr 1999 . 10196135 . 10.1074/jbc.274.16.10677 . free .
• Subramaniam VN, Loh E, Horstmann H, Habermann A, Xu Y, Coe J, Griffiths G, Hong W . Preferential association of syntaxin 8 with the early endosome . Journal of Cell Science . 113 . 6 . 997–1008 . Mar 2000 . 10.1242/jcs.113.6.997 . 10683148 .
• Sagiv Y, Legesse-Miller A, Porat A, Elazar Z . GATE-16, a membrane transport modulator, interacts with NSF and the Golgi v-SNARE GOS-28 . The EMBO Journal . 19 . 7 . 1494–504 . Apr 2000 . 10747018 . 310219 . 10.1093/emboj/19.7.1494 .
• Allan BB, Moyer BD, Balch WE . Rab1 recruitment of p115 into a cis-SNARE complex: programming budding COPII vesicles for fusion . Science . 289 . 5478 . 444–8 . Jul 2000 . 10903204 . 10.1126/science.289.5478.444 . 2000Sci...289..444A .
• Michaut M, Tomes CN, De Blas G, Yunes R, Mayorga LS . Calcium-triggered acrosomal exocytosis in human spermatozoa requires the coordinated activation of Rab3A and N-ethylmaleimide-sensitive factor . Proceedings of the National Academy of Sciences of the United States of America . 97 . 18 . 9996–10001 . Aug 2000 . 10954749 . 27650 . 10.1073/pnas.180206197 . 2000PNAS...97.9996M . free .
• Imai C, Sugai T, Iritani S, Niizato K, Nakamura R, Makifuchi T, Kakita A, Takahashi H, Nawa H . A quantitative study on the expression of synapsin II and N-ethylmaleimide-sensitive fusion protein in schizophrenic patients . Neuroscience Letters . 305 . 3 . 185–8 . Jun 2001 . 11403936 . 10.1016/S0304-3940(01)01844-4 . 20542930 .
• Kittler JT, Rostaing P, Schiavo G, Fritschy JM, Olsen R, Triller A, Moss SJ . The subcellular distribution of GABARAP and its ability to interact with NSF suggest a role for this protein in the intracellular transport of GABA(A) receptors . Molecular and Cellular Neurosciences . 18 . 1 . 13–25 . Jul 2001 . 11461150 . 10.1006/mcne.2001.1005 . 43244403 .

Notes and References

1. Web site: Entrez Gene: NSF N-ethylmaleimide-sensitive factor.
2. Wilson DW, Whiteheart SW, Wiedmann M, Brunner M, Rothman JE . A multisubunit particle implicated in membrane fusion . The Journal of Cell Biology . 117 . 3 . 531–8 . May 1992 . 1315316 . 2289450 . 10.1083/jcb.117.3.531 .
3. Hoyle J, Phelan JP, Bermingham N, Fisher EM . Localization of human and mouse N-ethylmaleimide-sensitive factor (NSF) gene: a two-domain member of the AAA family that is involved in membrane fusion . Mammalian Genome . 7 . 11 . 850–2 . Nov 1996 . 8875895 . 10.1007/s003359900249 . 21435412 .
4. Furst J, Sutton RB, Chen J, Brunger AT, Grigorieff N . Electron cryomicroscopy structure of N-ethyl maleimide sensitive factor at 11 A resolution . The EMBO Journal . 22 . 17 . 4365–74 . Sep 2003 . 12941689 . 202363 . 10.1093/emboj/cdg420 .
5. Book: Alberts B . Molecular biology of the cell . . 2008 . 978-0-8153-4105-5 .
6. Kuner T, Li Y, Gee KR, Bonewald LF, Augustine GJ . Photolysis of a caged peptide reveals rapid action of N-ethylmaleimide sensitive factor before neurotransmitter release . Proceedings of the National Academy of Sciences of the United States of America . 105 . 1 . 347–52 . Jan 2008 . 18172208 . 2224215 . 10.1073/pnas.0707197105 . 2008PNAS..105..347K . free .
7. Noel J, Ralph GS, Pickard L, Williams J, Molnar E, Uney JB, Collingridge GL, Henley JM . Surface expression of AMPA receptors in hippocampal neurons is regulated by an NSF-dependent mechanism . Neuron . 23 . 2 . 365–76 . Jun 1999 . 10399941 . 10.1016/S0896-6273(00)80786-2 . free .
8. Glick BS, Rothman JE . Possible role for fatty acyl-coenzyme A in intracellular protein transport . Nature . 326 . 6110 . 309–12 . 1987 . 3821906 . 10.1038/326309a0 . 1987Natur.326..309G . 4306469 .
9. Barnard RJ, Morgan A, Burgoyne RD . Stimulation of NSF ATPase activity by alpha-SNAP is required for SNARE complex disassembly and exocytosis . The Journal of Cell Biology . 139 . 4 . 875–83 . Nov 1997 . 9362506 . 2139964 . 10.1083/jcb.139.4.875 .
10. Hanson PI, Otto H, Barton N, Jahn R . The N-ethylmaleimide-sensitive fusion protein and alpha-SNAP induce a conformational change in syntaxin . The Journal of Biological Chemistry . 270 . 28 . 16955–61 . Jul 1995 . 7622514 . 10.1074/jbc.270.28.16955 . free .