Extension of Helix 12 in Munc18-1 Induces Vesicle Priming

Munch, A.S.; Kedar, G.H.; Weering, Jan R.T. van; Vázquez-Sánchez, Sonia; He, Enqi; André, Timon; Braun, Tobias; Söllner, Thomas H.; Verhage, Matthijs; Sørensen, Jakob Balslev

doi:10.1523/jneurosci.0007-16.2016

Cited by 50 publications

(79 citation statements)

References 61 publications

(72 reference statements)

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“…Note that Munc18 expression has been described to cause increased syntaxin-1 targeting to the plasma membrane (Gulyas-Kovacs et al. , 2007); however, in the present context, we always quantified the total syntaxin-1 immunolabeling of the cell, which is not significantly changed during short-term Munc18-1 overexpression (Munch et al. , 2016).…”

Section: Resultsmentioning

confidence: 97%

Regulation of Ca²⁺channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

Toft-Bertelsen

Ziomkiewicz

Houy

et al. 2016

MBoC

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Section: Resultsmentioning

confidence: 97%

Regulation of Ca²⁺channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

Toft-Bertelsen

Ziomkiewicz

Houy

et al. 2016

MBoC

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“…Mammalian MUNC18 and homologous C. elegans UNC-18 interact with SNARE protein complexes to regulate docking, priming, and exocytosis of SVs and DCVs (50,51,57,58,(61)(62)(63). Repetitive electrical stimulation of murine auditory and cerebellar synapses substantially raises the rate of NT release (15,54).…”

Section: Discussionmentioning

confidence: 99%

“…A homology-based model places serines 311 and 322 in a loop that links two antiparallel ␣-helices in the UNC-18 3a domain (55). Structures determined for homologous MUNC18 and its binding partners revealed that segments of the ␣-helix adjoining the C terminus of the specified loop mediate interactions with v-and t-SNARE complexes and syntaxin (61)(62)(63). This suggests that Ser 311 and Ser 322 are well positioned to participate in the reversible regulation of UNC-18 functions via phosphorylation and dephosphorylation.…”

Section: Discussionmentioning

confidence: 99%

A Calcium- and Diacylglycerol-Stimulated Protein Kinase C (PKC), Caenorhabditis elegans PKC-2, Links Thermal Signals to Learned Behavior by Acting in Sensory Neurons and Intestinal Cells

Land

Rubin

2017

Molecular and Cellular Biology

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Ca 2ϩ -and diacylglycerol (DAG)-activated protein kinase C (cPKC) promotes learning and behavioral plasticity. However, knowledge of in vivo regulation and exact functions of cPKCs that affect behavior is limited. We show that PKC-2, a Caenorhabditis elegans cPKC, is essential for a complex behavior, thermotaxis. C. elegans memorizes a nutrient-associated cultivation temperature (T c ) and migrates along the T c within a 17 to 25°C gradient. pkc-2 gene disruption abrogated thermotaxis; a PKC-2 transgene, driven by endogenous pkc-2 promoters, restored thermotaxis behavior in pkc-2 Ϫ/Ϫ animals. Cell-specific manipulation of PKC-2 activity revealed that thermotaxis is controlled by cooperative PKC-2-mediated signaling in both AFD sensory neurons and intestinal cells. Cold-directed migration (cryophilic drive) precedes T c tracking during thermotaxis. Analysis of temperature-directed behaviors elicited by persistent PKC-2 activation or inhibition in AFD (or intestine) disclosed that PKC-2 regulates initiation and duration of cryophilic drive. In AFD neurons, PKC-2 is a Ca 2ϩ sensor and signal amplifier that operates downstream from cyclic GMP-gated cation channels and distal guanylate cyclases. UNC-18, which regulates neurotransmitter and neuropeptide release from synaptic vesicles, is a critical PKC-2 effector in AFD. UNC-18 variants, created by mutating Ser 311 or Ser 322 , disrupt thermotaxis and suppress PKC-2-dependent cryophilic migration.KEYWORDS C. elegans signal integration, MUNC18 and UNC-18, calcium, diacylglycerol-activated PKC, cyclic GMP-gated channel, protein kinase C, regulation of learned behavior, sensory neuron, signal transduction, thermotaxis D iacylglycerol (DAG) and free cytoplasmic Ca 2ϩ mediate actions of hormones, neurotransmitters (NTs), and other stimuli that activate phospholipases C␤ and C␥ (1). Conventional protein kinase C isoforms (cPKCs ␣, ␤I, ␤II, and ␥) are widely expressed effectors of Ca 2ϩ and DAG in mammalian tissues (2-5). cPKCs are translocated to membranes and activated by binding Ca 2ϩ and DAG via their respective C2 and C1 domains. Thus, cPKCs are poised to receive, amplify, and disseminate the complete spectrum of intracellular signals generated by phospholipase C activation. Accordingly, cPKCs often couple extracellular stimuli to physiological processes that are coregulated by dynamic changes in Ca 2ϩ and DAG levels. In contrast, novel PKC isoforms (nPKCs ␦, , , and ) are activated by DAG alone.Some cell functions are redundantly regulated by combinations of PKCs. However, individual cPKCs can control key aspects of homeostasis or, when misregulated, promote pathological processes. For example, PKC␣ selectively regulates cardiac contrac-

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“…Munc18-1 stabilizes the t-SNARE complex, which is required for efficient docking (15). Furthermore, Munc18-1 induces Tc folding and the NTD conformational change, activating the t-SNARE complex to initiate SNARE zippering (8,32,33). Note that Munc18-1 also binds to SNAREs in other modes that play crucial roles in SNARE assembly (8,14,31).…”

Section: Discussionmentioning

confidence: 99%

“…The NTD of the native SNARE complex slowly assembles but readily disassembles upon vesicle undocking (8,9), limiting the overall rate of SNARE assembly and membrane fusion. Munc18-1 and other regulatory proteins enhance NTD assembly to initiate SNARE zippering (17,31,32). Vc-57 significantly increased the rate and stability of NTD assembly, suggesting that this peptide efficiently activated the t-SNARE complex to initiate SNARE zippering.…”

Section: Effect Of T-snare Conformational Switch On Ternary Snare Zipmentioning

confidence: 99%

Stability, folding dynamics, and long-range conformational transition of the synaptic t-SNARE complex

Zhang

Rebane

et al. 2016

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

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Synaptic soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) couple their stepwise folding to fusion of synaptic vesicles with plasma membranes. In this process, three SNAREs assemble into a stable four-helix bundle. Arguably, the first and rate-limiting step of SNARE assembly is the formation of an activated binary target (t)-SNARE complex on the target plasma membrane, which then zippers with the vesicle (v)-SNARE on the vesicle to drive membrane fusion. However, the t-SNARE complex readily misfolds, and its structure, stability, and dynamics are elusive. Using single-molecule force spectroscopy, we modeled the synaptic t-SNARE complex as a parallel three-helix bundle with a small frayed C terminus. The helical bundle sequentially folded in an N-terminal domain (NTD) and a C-terminal domain (CTD) separated by a central ionic layer, with total unfolding energy of ∼17 k B T, where k B is the Boltzmann constant and T is 300 K. Peptide binding to the CTD activated the t-SNARE complex to initiate NTD zippering with the v-SNARE, a mechanism likely shared by the mammalian uncoordinated-18-1 protein (Munc18-1). The NTD zippering then dramatically stabilized the CTD, facilitating further SNARE zippering. The subtle bidirectional t-SNARE conformational switch was mediated by the ionic layer. Thus, the t-SNARE complex acted as a switch to enable fast and controlled SNARE zippering required for synaptic vesicle fusion and neurotransmission.t-SNARE complex | SNARE four-helix bundle | SNARE assembly | membrane fusion | optical tweezers S ynaptic soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) mediate fast and calcium-triggered fusion of synaptic vesicles to presynaptic plasma membranes required for neurotransmission (1). They consist of VAMP2 (vesicle associated membrane protein 2, also called synaptobrevin 2) anchored on vesicles (v-SNARE) and syntaxin and SNAP-25 (synaptosome associated protein 25) located on target plasma membranes (t-SNAREs) (2). These SNAREs contain characteristic SNARE motifs of ∼60 amino acids (3) (Fig. 1A). Syntaxin and SNAP-25 can form a 1:1 t-SNARE complex (4-6). During membrane fusion, the t-and v-SNAREs join to form an extraordinarily stable four-helix bundle (3, 7-10). In the core of the bundle are 15 layers of hydrophobic amino acids and a central ionic layer containing three glutamines and one arginine. Whereas the zippering energy and kinetics between t-and v-SNAREs have recently been measured (8, 9), the structure, stability, and dynamics of the t-SNARE complex have not been well understood.The structure and dynamics of the t-SNARE complex are crucial for SNARE assembly and membrane fusion. Formation of the t-SNARE complex is likely an obligate intermediate before SNARE zippering (6,(11)(12)(13)(14). A preformed t-SNARE complex docks the vesicles to plasma membranes (15) and boosts the speed, strength, and accuracy of SNARE zippering (5, 9, 16). Furthermore, the t-SNARE complex is an important target for proteins that regulate SNAR...

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Extension of Helix 12 in Munc18-1 Induces Vesicle Priming

Cited by 50 publications

References 61 publications

Regulation of Ca²⁺channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

Regulation of Ca²⁺channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

A Calcium- and Diacylglycerol-Stimulated Protein Kinase C (PKC), Caenorhabditis elegans PKC-2, Links Thermal Signals to Learned Behavior by Acting in Sensory Neurons and Intestinal Cells

Stability, folding dynamics, and long-range conformational transition of the synaptic t-SNARE complex

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Extension of Helix 12 in Munc18-1 Induces Vesicle Priming

Cited by 50 publications

References 61 publications

Regulation of Ca2+channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

Regulation of Ca2+channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

A Calcium- and Diacylglycerol-Stimulated Protein Kinase C (PKC), Caenorhabditis elegans PKC-2, Links Thermal Signals to Learned Behavior by Acting in Sensory Neurons and Intestinal Cells

Stability, folding dynamics, and long-range conformational transition of the synaptic t-SNARE complex

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Regulation of Ca²⁺channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

Regulation of Ca²⁺channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters