Regulatory roles of complexins in neurotransmitter release from mature presynaptic nerve terminals

Ono, Shoichiro; Baux, Gérard; Sekiguchi, Mariko; Fossier, Philippe; Morel, Nicolas; Nihonmatsu, Itsuko; Hirata, Kazuo; Awaji, Takeo; Takahashi, Seiichi; Takahashi, Masami

doi:10.1046/j.1460-9568.1998.00225.x

Cited by 81 publications

(69 citation statements)

References 60 publications

(75 reference statements)

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“…1 H- 15 N HSQC experiments were acquired using spectral widths of 7600 and 2000 Hz in the 1 H and 15 N dimensions, respectively. Data sets consisted of 2 ϫ 100 FIDs of 768 complex points each and were zero filled to yield matrices of 512 ϫ 512 real points after Fourier transformation and removal of the aliphatic part of the spectrum.…”

Section: Methodsmentioning

confidence: 99%

“…The numer of transients per FID was adjusted to yield total acquisition times of 0.5-36 h, depending on the protein concentration. Sequential assignments were obtained from a series of three-dimensional pulse field gradient-enhanced 15 N-edited and triple resonance experiments using 15 N-labeled (1 mM) and 15 N, The mixing times were 45 ms, 120 ms and 18 ms for the TOCSY-HSQC, NOESY-HSQC, and (H)C(CO)NH-TOCSY experiments, respectively. Linear prediction was used to double the number of points in the F2 dimension of all spectra.…”

Section: Methodsmentioning

confidence: 99%

“…In vitro, complexins bind to assembled SNAREs and compete with ␣-SNAP for binding (12), suggesting that they are involved in the regulation of the SNARE assembly-disassembly cycle. Both complexins are colocalized with neuronal SNAREs in presynaptic nerve terminals, although cytoplasmic pools are also present, particularly during early stages of neuronal maturation (15).…”

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confidence: 99%

“…When the intracellular concentration of complexin was increased by microinjection or by overexpression, a moderate reduction of neurotransmitter release was observed. Injection of an anti-complexin antibody increased transmitter release, suggesting that complexins may function as negative regulators (15,16). Disruption of the complexin II gene in mice resulted in viable mice with all parameters of synaptic transmission being normal except long term potentiation (17).…”

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confidence: 99%

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Selective Interaction of Complexin with the Neuronal SNARE Complex

Pabst¹,

Hazzard²,

Antonin³

et al. 2000

Journal of Biological Chemistry

167

188

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Complexins are evolutionarily conserved proteins that specifically bind to soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes and thus may regulate SNARE function. Using purified proteins, we have performed a detailed analysis of the structure of complexin and of its interaction with SNARE proteins. NMR spectroscopy revealed that isolated complexins have no tertiary structure but contain an unusual ␣-helical middle domain of approximately 58 amino acids that overlaps with the most highly conserved region of the molecules. Complexins form a stable stoichiometric complex with the central domain of the ternary SNARE complex, whereas no binding was observed to monomeric SNAREs. Using a combination of limited proteolysis, deletion mutagenesis, and NMR spectroscopy, we found that the helical middle region of complexin is responsible for binding to the SNARE complex. Binding was highly sensitive to substitution of syntaxin 1 or synaptobrevin 2 with other SNARE homologs but less sensitive to substitution of SNAP-25. In addition, a stretch of 12 amino acids in the middle of the SNARE motif of syntaxin 1A was able to confer binding activity to the non-binding relative syntaxin 4. Furthermore, disassembly of ternary complexes is not affected by complexins. We conclude that complexins are specific ligands of the neuronal core complex that bind with a central ␣-helical domain, probably to the middle of the surface groove formed by synaptobrevin and syntaxin. Complexins may regulate the function of ternary complexes and control membrane fusion through this interaction.Intracellular membrane fusion events are mediated by conserved sets of membrane-bound proteins referred to as SNAREs 1 (acronym for soluble N-ethylmaleimide-sensitive factor attachment protein receptors) (1). SNAREs comprise a family of proteins that is distinguished by the presence of the SNARE motif, a homologous stretch of approximately 60 amino acids that is usually localized adjacent to the membrane anchor domains (2-4). Best characterized are SNARE proteins functioning in neuronal exocytosis. They include the synaptic vesicle protein synaptobrevin (also referred to as vesicle-associated membrane protein), and the synaptic plasma membrane proteins SNAP-25 and syntaxin 1. These proteins form a stable ternary complex, the core complex, that can be reversibly disassembled by the ATPase NSF (N-ethylmaleimide-sensitive factor) and additional cofactors termed SNAPs (for soluble NSF attachment proteins) (5).Studies performed largely on recombinant proteins in solution have revealed a detailed picture of SNARE complex assembly. Of the monomeric SNAREs, only syntaxin 1 is partially ␣-helical, whereas both SNAP-25 and synaptobrevin are largely unstructured. Upon assembly, a dramatic increase in ␣-helical content is observed suggesting major conformational changes (6, 7). Interactions in the complex are largely confined to the SNARE motifs. X-ray crystallography revealed that the assembled core complex consists of an elongated bund...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Selective Interaction of Complexin with the Neuronal SNARE Complex

Pabst¹,

Hazzard²,

Antonin³

et al. 2000

Journal of Biological Chemistry

167

188

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“…Moreover, the normal roles of synaptic proteins should not be neglected; ie their decreased expression may be important as a marker of synaptic dysfunction as well as of altered synaptic structural organisation. Notably, the complexins are involved in neurotransmitter release 21 and long-term potentiation, 22 and impairment of either activity as a result of decreased cx availability might contribute to compromised hippocampal functioning.…”

Section: Complexin Expression In Schizophreniamentioning

confidence: 99%

Hippocampal synaptic pathology in schizophrenia, bipolar disorder and major depression: a study of complexin mRNAs

2000

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Complexin (cx) I and cx II are synaptic proteins preferentially expressed by inhibitory and excitatory hippocampal neurons respectively. We previously reported decreased hippocampal formation cx mRNA and protein expression in schizophrenia, with a greater loss of cx II than cx I. The present in situ hybridization study was both an attempt at replication, and an extension to include bipolar and unipolar mood disorders, using sections from the Stanley Foundation brain series. In schizophrenia, both mRNAs were decreased in some hippocampal subfields, especially CA4, but were preserved in subiculum. The cx II/cx I mRNA ratio was unchanged. In bipolar disorder, the mRNAs were reduced in CA4, subiculum and parahippocampal gyrus, with the deficit in subiculum being diagnostically specific. No alterations in cx mRNAs were found in major depression. Treatment of rats with antipsychotics (haloperidol or chlorpromazine) for 2 weeks had no effect on hippocampal cx mRNAs. These data replicate the finding of decreased cx I and cx II expression in the hippocampus in schizophrenia and show a similar or greater abnormality in bipolar disorder. Non-replication of the cx II Ͼ cx I mRNA loss in schizophrenia means that the hypothesis of a preferential involvement of excitatory connections was not supported. The results extend the emerging evidence that altered circuitry may be a component of the neuroanatomy of both schizophrenia and bipolar mood disorder. Molecular Psychiatry (2000) 5, 425-432.

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