Ca2+ Regulates the Interaction between Synaptotagmin and Syntaxin 1

Chapman, Edwin R.; Hanson, Phyllis I.; An, Seong Jin; Jahn, Reinhard

doi:10.1074/jbc.270.40.23667

Cited by 356 publications

(308 citation statements)

References 46 publications

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“…6, this mutant is not an effective inhibitor of secretion. We note that the K326,327A mutant is able to bind to SNAREs (Chapman et al 1998), and this interaction requires both C2A and C2B (Chapman et al 1995; Davis et al 1999). These data indicate that C2B is not simply misfolded.…”

Section: Resultsmentioning

confidence: 79%

“…This is in striking contrast to the C2A domain of synaptotagmin, in which each of the Ca 2+ ligands are essential for binding to anionic phospholipids (Zhang et al 1998; Bai et al 2000). The interaction of synaptotagmin with SNAREs exhibits an intermediate dependence on Ca 2+ ligands within C2A: some mutations are tolerated, whereas other mutations have strong disruptive effects (Chapman et al 1995; Bai et al 2000). There appear to be multiple modes by which Ca 2+ binding can regulate the interactions of the C2 domains of synaptotagmin with effector molecules.…”

Section: Resultsmentioning

confidence: 99%

“…This complex is composed of the target SNAREs (t-SNAREs) syntaxin and SNAP-25 and the vesicle SNARE synaptobrevin (Söllner et al 1993); assembly of the complex is necessary (Littleton et al 1998; Chen et al 1999) and may be sufficient (Weber et al 1998) for exocytotic membrane fusion. Synaptotagmin forms direct contacts with both t-SNAREs at all stages of the SNARE complex assembly (data not shown; Chapman et al 1995; Schiavo et al 1997; Davis et al 1999; Gerona et al 2000) and can bind SNAREs and interact with membranes at the same time (Davis et al 1999). These interactions suggest that synaptotagmin may regulate SNARE-mediated membrane fusion by modulating the conformation and/or assembly of SNARE complexes.…”

Section: Introductionmentioning

confidence: 97%

“…The C2A domain is connected to C2B by a short tether and the tandem C2 domains cooperate to form complexes with components of the soluble N -ethyl maleimide-sensitive factor attachment protein receptor (SNARE) complex (Chapman et al 1995, Chapman et al 1996; Davis et al 1999; Gerona et al 2000). This complex is composed of the target SNAREs (t-SNAREs) syntaxin and SNAP-25 and the vesicle SNARE synaptobrevin (Söllner et al 1993); assembly of the complex is necessary (Littleton et al 1998; Chen et al 1999) and may be sufficient (Weber et al 1998) for exocytotic membrane fusion.…”

Section: Introductionmentioning

confidence: 99%

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The C2b Domain of Synaptotagmin Is a Ca2+–Sensing Module Essential for Exocytosis

Desai

Vyas

Earles

et al. 2000

The Journal of Cell Biology

116

165

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The synaptic vesicle protein synaptotagmin I has been proposed to serve as a Ca2+ sensor for rapid exocytosis. Synaptotagmin spans the vesicle membrane once and possesses a large cytoplasmic domain that contains two C2 domains, C2A and C2B. Multiple Ca2+ ions bind to the membrane proximal C2A domain. However, it is not known whether the C2B domain also functions as a Ca2+-sensing module. Here, we report that Ca2+ drives conformational changes in the C2B domain of synaptotagmin and triggers the homo- and hetero-oligomerization of multiple isoforms of the protein. These effects of Ca2+ are mediated by a set of conserved acidic Ca2+ ligands within C2B; neutralization of these residues results in constitutive clustering activity. We addressed the function of oligomerization using a dominant negative approach. Two distinct reagents that block synaptotagmin clustering potently inhibited secretion from semi-intact PC12 cells. Together, these data indicate that the Ca2+-driven clustering of the C2B domain of synaptotagmin is an essential step in excitation-secretion coupling. We propose that clustering may regulate the opening or dilation of the exocytotic fusion pore.

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Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The C2b Domain of Synaptotagmin Is a Ca2+–Sensing Module Essential for Exocytosis

Desai

Vyas

Earles

et al. 2000

The Journal of Cell Biology

116

165

View full text Add to dashboard Cite

show abstract

“…First, synaptobrevin and SNAP-25/syntaxin heterodimers present in the same vesicle may have an inappropriate orientation for the formation of a heterotrimer as opposed to synaptobrevin in a docked vesicle facing plasmalemmal syntaxin and SNAP-25. Second, protein-protein (or protein-lipid) interactions, for example binding of synaptotagmin [42,43], complexins [44] or secl homologues [4547] to syntaxin, may prevent the formation of the heterotrimers in the vesicular membrane. Specifically, n-secl inhibits the interaction of other proteins with syntaxin, including synaptobrevin and SNAP-25 [5].…”

Section: Discussionmentioning

confidence: 99%

Adrenal chromaffin cells contain functionally different SNAP‐25 monomers and SNAP‐25/syntaxin heterodimers

Höhne-Zell¹,

Gratzl²

1996

FEBS Letters

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C 2‐Domain Proteins Involved in Membrane Traffic

Rizo

2004

Handbook of Metalloproteins

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C 2 ‐domains are the second‐most abundant Ca 2+ ‐binding modules in nature. Their most common activity is Ca 2+ ‐dependent phospholipid binding, but other types of interactions have been observed for these versatile protein modules. A variety of proteins involved in membrane traffic contain multiple C 2 ‐domains, which often appear as two tandem C 2 ‐domains as in the case of synaptotagmins and rabphilin. The structures of the C 2 ‐domains of these proteins consist of a conserved β‐sandwich, formed by two four‐stranded β‐sheets, with variable loops at the top and the bottom that sometimes contain α‐helices. Multiple Ca 2+ ‐ions bind in a tight cluster at the top loops, usually without inducing substantial conformational changes. Instead, electrostatic changes caused by Ca 2+ binding induce the Ca 2+ ‐dependent interactions of C 2 ‐domains, which can also be aided by hydrophobic interactions and partial coordination of Ca 2+ by the target molecules. Extensive analysis of the structure and Ca 2+ ‐binding properties of the two synaptotagmin 1 C 2 ‐domains has helped design genetic experiments that have strongly supported the notion that this protein acts as the major Ca 2+ sensor in neurotransmitter release. These studies have also suggested that Ca 2+ ‐dependent phospholipid binding underlies the function of synaptotagmin 1 in triggering release.

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Ca2+ Regulates the Interaction between Synaptotagmin and Syntaxin 1

Cited by 356 publications

References 46 publications

The C2b Domain of Synaptotagmin Is a Ca2+–Sensing Module Essential for Exocytosis

The C2b Domain of Synaptotagmin Is a Ca2+–Sensing Module Essential for Exocytosis

Adrenal chromaffin cells contain functionally different SNAP‐25 monomers and SNAP‐25/syntaxin heterodimers

C 2‐Domain Proteins Involved in Membrane Traffic

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