Sec1/Munc18-like (SM) proteins functionally interact with SNARE proteins in vesicular fusion. Despite their high sequence conservation, structurally disparate binding modes for SM proteins with syntaxins have been observed. Several SM proteins appear to bind only to a short peptide present at the N terminus of syntaxin, designated the N-peptide, while Munc18a binds to a 'closed' conformation fo...

We have screened for proteins that interact with v-SNAREs of the late secretory pathway in the yeast Saccharomyces cerevisiae. A novel protein, designated Vsm1, binds tightly to the Snc2 v-SNARE in the two-hybrid system and can be coimmunoprecipitated with Snc1 or Snc2 from solubilized yeast cell extracts. Disruption of the VSM1 gene results in an increase of proteins secreted into the medium b...

A hallmark of eukaryotic cells is the ability to segregate biochemical reactions within membrane-bound organelles. SNARE proteins, the protein family that mediate membrane fusion of vesicles trafficking between organelles, are conserved through phylogeny from yeast to man, as well as throughout the cell from the endoplasmic reticulum to the plasma membrane. SNAREs are integral membrane proteins...

To enable fusion between biological membranes, t-SNAREs and v-SNARE present in opposing bilayers, interact and assemble in a circular configuration forming ring-complexes, which establish continuity between the opposing membranes, in presence of calcium ions. The size of a t-/v-SNARE ring complex is dictated by the curvature of the opposing membrane. Hence smaller vesicles form small SNARE-ring...

Neurons communicate at chemical synapses via exocytosis of synaptic vesicles containing neurotransmitter, a process mediated by SNARE proteins. SEPT5, a predominantly brainspecific member of the septin family of GDP/GTP-binding cytoskeletal proteins, binds the SNARE STX1A. Furthermore, SEPT5 inhibits exocytosis and has been implicated in the organization of synaptic vesicles within the presynap...

Trans-QabcR-SNARE pairing on opposing membranes is crucial for eukaryotic membrane fusion, but how selective pairs of Qabc- and R-SNARE proteins regulate membrane fusion specificity remains elusive. Here, we studied 14 purified full-length SNAREs that function in yeast endoplasmic reticulum (ER)-Golgi, intra-Golgi, endosomal, and vacuolar transport by comprehensively testing cis-QabcR-SNARE ass...

Target membrane proteins, SNAP-25 and syntaxin (t-SNARE), and secretory vesicleassociated membrane protein (v-SNARE), are part of the conserved protein complex involved in fusion of opposing bilayers in biological systems in the presence of calcium. It is known that SNARE interaction allows opposing bilayers to come close within a distance of approximately 3 Å, enabling calcium to drive membran...

To further characterize the molecular mechanisms of platelet function, we have sought to identify some of the proteins that mediate the secretory events of the platelet release reaction. We report that platelets contain the general elements of the membrane transport apparatus: N-ethylmaleimide sensitive fusion protein (NSF), p115/transcytosis-associated protein (p115/TAP), and the soluble NSF a...

The KChIPs (K(+) channel-interacting proteins) are EF hand-containing proteins required for the traffic of channel-forming Kv4 K(+) subunits to the plasma membrane. KChIP1 is targeted, through N-terminal myristoylation, to intracellular vesicles that appear to be trafficking intermediates from the ER (endoplasmic reticulum) to the Golgi but differ from those underlying conventional ER-Golgi tra...

SNARE proteins direct membrane fusion events required for platelet granule secretion. These proteins are oriented in cell membranes such that most of the protein resides in a cytosolic compartment. Evaluation of SNARE protein localization in activated platelets using immunonanogold staining and electron microscopy, however, demonstrated expression of SNAP-23 and syntaxin-2 on the extracellular ...