Mso1p Regulates Membrane Fusion through Interactions with the Putative N-Peptide–binding Area in Sec1p Domain 1

Weber, Marion; Chernov, Konstantin G.; Turakainen, Hilkka; Wohlfahrt, Gerd; Pajunen, Maria I.; Savilahti, Harri; Jäntti, Jussi

doi:10.1091/mbc.e09-07-0546

Cited by 17 publications

(38 citation statements)

References 56 publications

(114 reference statements)

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“…A group of membrane transport factors, including Mso1 and Rabs, are known to interact with both SNAREs and SM proteins (63,(65)(66)(67). These SM-interacting factors may play alternative/compensatory roles in initiating the fusion complex formation when the N-peptide binding mode is lacking or inhibited.…”

Section: Discussionmentioning

confidence: 99%

“…These SM-interacting factors may play alternative/compensatory roles in initiating the fusion complex formation when the N-peptide binding mode is lacking or inhibited. Intriguingly, Mso1 occupies the same binding site on SM proteins as the Npeptide and has been postulated to mimic the N-peptide in facilitating membrane fusion (66). Functional compensation by alternative initiation factors may explain the discrepancies over the observed consequences of N-peptide disruption in vesicle fusion (61,68,69).…”

Section: Discussionmentioning

confidence: 99%

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Syntaxin N-terminal peptide motif is an initiation factor for the assembly of the SNARE–Sec1/Munc18 membrane fusion complex

Rathore

Bend

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

116

142

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Intracellular membrane fusion is mediated by the concerted action of N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and Sec1/Munc18 (SM) proteins. During fusion, SM proteins bind the N-terminal peptide (N-peptide) motif of the SNARE subunit syntaxin, but the function of this interaction is unknown. Here, using FRET-based biochemical reconstitution and Caenorhabditis elegans genetics, we show that the N-peptide of syntaxin-1 recruits the SM protein Munc18-1/nSec1 to the SNARE bundle, facilitating their assembly into a fusion-competent complex. The recruitment is achieved through physical tethering rather than allosteric activation of Munc18-1. Consistent with the recruitment role, the Npeptide is not spatially constrained along syntaxin-1, and it is functional when translocated to another SNARE subunit SNAP-25 or even when simply anchored in the target membrane. The N-peptide function is restricted to an early initiation stage of the fusion reaction. After association, Munc18-1 and the SNARE bundle together drive membrane merging without further involving the N-peptide. Thus, the syntaxin N-peptide is an initiation factor for the assembly of the SNARE-SM membrane fusion complex.I ntracellular membrane fusion is the basis of a wide range of fundamental biological processes, including organelle maintenance, hormone secretion, and inside-outside distribution of receptors and transporters. The merging of intracellular membrane bilayers is mediated by a fusion complex comprised of SNAREs and Sec1/Munc18 (SM) proteins (1). The core of the fusion machinery is the trans-SNARE complex (SNAREpin) formed by the pairing of the vesicle-rooted SNARE (v-SNARE) with the target membrane-associated SNAREs (t-SNAREs) (2-5). N-to C-terminal zippering of the trans-SNARE complex brings two membranes into close apposition and helps to overcome the energy barrier for fusion (6-10). SM proteins are soluble factors of 60-70 kDa that directly interact with their cognate trans-SNARE complexes to promote the speed and specificity of a fusion reaction (11)(12)(13)(14).Each fusion pathway in the cell requires a specific subset of SNAREs and SM proteins (15). The most intensely studied form of intracellular membrane fusion is calcium-triggered neurotransmitter release at the chemical synapse, which serves as the brain's major form of cell-cell communication (15)(16)(17)(18)(19). Neurotransmitter secretion is mediated by the fusion of exocytic vesicles with the plasma membrane and requires the v-SNARE vesicle-associated membrane protein 2 (VAMP2; also known as synaptobrevin-2), the t-SNAREs syntaxin-1 and soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP)-25, and the SM protein Munc18-1/ nSec1 (UNC-18 in nematodes and ROP in flies) (20-28).The interaction between SNAREs and SM proteins involves multiple binding modes. The primary target of SM proteins is believed to be the four-helix SNARE bundle (29-31). Assembled from the SNARE motifs and the transmembrane domains of t-and vSNAREs (4, 5), the SNARE bun...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Syntaxin N-terminal peptide motif is an initiation factor for the assembly of the SNARE–Sec1/Munc18 membrane fusion complex

Rathore

Bend

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

116

142

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“…The mss4ts and wild-type cells were transformed with plasmids expressing YFP(C)-MSO1 and SEC1-Venus(N) and subjected to analysis using the bimolecular fluorescence complementation (BiFC) assay (Hu et al. , 2002; Skarp et al ., 2008; Weber et al ., 2010). In mss4ts cells, Mso1p–Sec1p BiFC signal persisted at the permissive temperature 24°C but was partially mislocalized along the plasma membrane (Supplemental Figure S1, A and B).…”

Section: Resultsmentioning

confidence: 99%

“…In line with the previous results, no BiFC signal was obtained for Mso1p(1–39) and Mso1p(136–210), which lack the Sec1p-binding domain (Knop et al. , 2005; Weber et al. , 2010).…”

Section: Resultsmentioning

confidence: 99%

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A conserved regulatory mode in exocytic membrane fusion revealed by Mso1p membrane interactions

Weber-Boyvat

Zhao

Aro

et al. 2013

MBoC

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Applications of the Bacteriophage Mu In Vitro Transposition Reaction and Genome Manipulation via Electroporation of DNA Transposition Complexes

Haapa-Paananen

Savilahti

2017

Methods in Molecular Biology

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The capacity of transposable elements to insert into the genomes has been harnessed during the past decades to various in vitro and in vivo applications. This chapter describes in detail the general protocols and principles applicable for the Mu in vitro transposition reaction as well as the assembly of DNA transposition complexes that can be electroporated into bacterial cells to accomplish efficient gene delivery. These techniques with their modifications potentiate various gene and genome modification applications, which are discussed briefly here, and the reader is referred to the original publications for further details.

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Mso1p Regulates Membrane Fusion through Interactions with the Putative N-Peptide–binding Area in Sec1p Domain 1

Abstract: We show that the putative N-peptide binding area in Sec1p domain 1 is important for Mso1p binding and that Mso1p can interact with Sso1p and Sso2p. Our results suggest that Mso1p mimics N-peptide binding to facilitate membrane fusion.

Cited by 17 publications

References 56 publications

Syntaxin N-terminal peptide motif is an initiation factor for the assembly of the SNARE–Sec1/Munc18 membrane fusion complex

Syntaxin N-terminal peptide motif is an initiation factor for the assembly of the SNARE–Sec1/Munc18 membrane fusion complex

A conserved regulatory mode in exocytic membrane fusion revealed by Mso1p membrane interactions

Applications of the Bacteriophage Mu In Vitro Transposition Reaction and Genome Manipulation via Electroporation of DNA Transposition Complexes

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