Munc18-1 catalyzes neuronal SNARE assembly by templating SNARE association

Jiao, Junyi; He, Mengze; Port, Sarah A.; Baker, Richard W.; Xu, Yuntao; Qu, Hong; Xiong, Yujian; Wang, Yukun; Jin, Hong; Eisemann, Travis; Hughson, Frederick M.; Zhang, Yongli

doi:10.1101/413724

Cited by 15 publications

(31 citation statements)

References 54 publications

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“…Based on our results, no energetic alteration is recorded. This is in accordance with the results of single-molecule force spectroscopy showing no difference between the WT and P335L with respect to the closed state of syntaxin 1A 45 . Note that a missense mutation at the same position (P335S) is labeled as likely pathogenic, and its interaction energy is strongly affected (ΔΔG = 2.70 kcal/mol).…”

Section: Main Textsupporting

confidence: 92%

Structural analysis of de novo STXBP1 mutation in complex with syntaxin 1A reveals a major alteration in the interaction interface in a child with developmental delay and spasticity

Banne

Falik‐Zaccai

Brielle

et al. 2019

Preprint

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STXBP1, also known as Munc-18, is a master regulator of neurotransmitter release and synaptic function in the human brain through its direct interaction with syntaxin 1A. STXBP1 related disorders are well characterized and cover a diverse range of neurological and neurodevelopmental conditions. Through exome sequencing of a child with developmental delay, hypotonia and spasticity, we found a novel de novo insertion mutation of three nucleotides in the STXBP1 coding region, resulting in an additional arginine after position 39 (R39dup).Inconclusive results from state-of-the-art variant prediction tools mandated a structure-based approach using molecular dynamics (MD) simulations of the STXBP1-syntaxin 1A complex.Comparison of the interaction interfaces of the wild type and the R39dup complexes revealed a reduced interaction surface area in the mutant, leading to destabilization of the interaction. We applied the same MD methodology to 7 additional previously reported STXBP1 mutations. We find that the stability of the STXBP1-syntaxin 1A interface correlates with the reported clinical phenotypes. We illustrate a direct link between a patient's genetic variations and the observed clinical phenotype through protein structure, dynamics, and function.

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Section: Main Textsupporting

confidence: 92%

Structural analysis of de novo STXBP1 mutation in complex with syntaxin 1A reveals a major alteration in the interaction interface in a child with developmental delay and spasticity

Banne

Falik‐Zaccai

Brielle

et al. 2019

Preprint

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“…In contrast, the basal SNAREdriven fusion (without Munc18-1) was not affected by the mutation ( Figures 2C-2E and S2). The selective involvement of the juxtamembrane motif in the SNARE-Munc18-1-mediated fusion reaction is consistent with the discovery that basal SNAREdriven fusion is fundamentally distinct from the SM protein-assisted fusion pathway (Baker et al, 2015;Jiao et al, 2018;Yu et al, 2018). The SNARE-SM-mediated fusion reaction, but not basal SNARE-driven fusion, recapitulates intracellular vesicle fusion Yu et al, 2015Yu et al, , 2018.…”

Section: The Juxtamembrane Motif Of Vamp2 Is Required For Snare-munc1supporting

confidence: 81%

“…This observation can be explained by the discovery that the Vc peptide-assisted fusion reaction mimics SNARE-SM-mediated membrane fusion rather than the basal fusion reaction . Although the juxtamembrane motif of VAMP2 can associate with t-SNARE and Munc18-1 Xu et al, 2010), our and others' data showed that the juxtamembrane motif is dispensable for SNARE-SNARE and SNARE-Munc18-1 interactions (Figure 3; Jiao et al, 2018).…”

Section: Discussionmentioning

confidence: 41%

Intracellular Vesicle Fusion Requires a Membrane-Destabilizing Peptide Located at the Juxtamembrane Region of the v-SNARE

Rathore

Liu

et al. 2019

Cell Reports

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“…When superimposed these structures implied that Vps33 templates the initial assembly of the trans-SNARE complex, allowing the trans-complex to transit into a metastable "half-zipped" intermediate. Single-molecule force spectroscopy experiments strongly supported this interpretation (Jiao et al, 2018;Ma et al, 2015). It remains unclear whether the templating mechanism is generalizable to all SMs, and it is 60 unclear to what extent SMs promote SNARE-mediated fusion through additional general or pathway-specific mechanisms.We have turned our attention to Sly1, the ER-Golgi SM.…”

mentioning

confidence: 94%

Golgi SM protein Sly1 promotes productivetrans-SNARE complex assembly through multiple mechanisms

Duan

Gao

Banfield

2020

Preprint

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SNARE chaperones of the Sec1/mammalian Unc-18 (SM) family have critical roles in SNAREmediated membrane fusion. Using SNARE and Sly1 mutants, and a new in vitro assay of fusion, we separate and assess proposed mechanisms through which Sly1 augments fusion: (i) opening the closed conformation of the Qa-SNARE Sed5; (ii) close-range tethering of vesicles 5 to target organelles, mediated by the Sly1-specific regulatory loop; and (iii) preferential nucleation of productive trans-SNARE complexes. We show that all three mechanisms are important and operate in parallel, and we present evidence that close-range tethering is particularly important for trans-complex assembly when cis-SNARE assembly is a competing process. In addition, the autoinhibitory N-terminal Habc domain of Sed5 has at least two 10 positive activities: the Habc domain is needed for correct Sed5 localization, and it directly promotes Sly1-dependent fusion. Remarkably, "split Sed5," with the Habc domain present only as a soluble fragment, is functional both in vitro and in vivo.In addition to SNAREs and tethering factors, proteins of the Sec1/mammalian Unc-18 (SM) family have critical roles in SNARE-mediated fusion (Carr and Rizo, 2010;Rizo and Sudhof, 2012;Sudhof and Rothman, 2009). The first SM proteins identified through genetic 35 screens were Vps33a (carnation in Drosophila) and Saccharomyces cerevisiae Sec1 (UNC-18 in Caenorabditis elegans; Munc18-1 or nSec1 in mammals; Novick et al., 1979;Patterson, 1932).Despite their early identification and clear importance, and despite major efforts by many laboratories, the general mechanisms of SM function are only now emerging. All SM proteins exhibit strong evolutionary and structural homology, but they interact with cognate SNARE 40 proteins in very different ways. For example, yeast Sly1, yeast Vps45, and Munc18-1 all interact with short N-peptides at the amino termini of their cognate Qa-SNARE proteins (Bracher and Weissenhorn, 2002;Carpp et al., 2006;Dulubova et al., 2002;Furgason et al., 2009; Grabowski and Gallwitz, 1997;Yamaguchi et al., 2002). In contrast, Qa-SNARE N-peptide interactions do not occur with human or yeast Vps33, or with yeast Sec1 (Baker et al., 2015; Dulubova et al., 45 2001;Lobingier and Merz, 2012;Togneri et al., 2006). We have called SM proteins that interact with Qa-SNARE N-peptides Class I, and those that do not, Class II (Lobingier and Merz, 2012).Early structural and biochemical studies revealed that Munc18-1 tightly binds the Qa-SNARE Syntaxin-1A in its closed conformation, suggesting an inhibitory role for Munc18-1. (Dulubova et al., 1999;Misura et al., 2000;Yang et al., 2000). However, the emerging consensus 50 is that the core and evolutionarily conserved role of SM proteins is positive, rather than inhibitory. Specifically, SM proteins are hypothesized to nucleate and stabilize fusioncompetent trans-SNARE complexes (Carr and Rizo, 2010;Sudhof and Rothman, 2009;Toonen and Verhage, 2003;Yoon and Munson, 2018). A breakthrough was achieved in 2015 with two structure...

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Munc18-1 catalyzes neuronal SNARE assembly by templating SNARE association

Cited by 15 publications

References 54 publications

Structural analysis of de novo STXBP1 mutation in complex with syntaxin 1A reveals a major alteration in the interaction interface in a child with developmental delay and spasticity

Structural analysis of de novo STXBP1 mutation in complex with syntaxin 1A reveals a major alteration in the interaction interface in a child with developmental delay and spasticity

Intracellular Vesicle Fusion Requires a Membrane-Destabilizing Peptide Located at the Juxtamembrane Region of the v-SNARE

Golgi SM protein Sly1 promotes productivetrans-SNARE complex assembly through multiple mechanisms

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