Rab GTPases, their effectors, SNAREs of the R, Qa, Qb, and Qc families, and SM SNARE-binding proteins catalyze intracellular membrane fusion. At the vacuole/lysosome, they are integrated by the homotypic fusion and vacuole protein sorting (HOPS) complex. Two HOPS subunits bind vacuolar Rabs for tethering, another binds the Qc SNARE, and a fourth HOPS subunit, an SM protein, has conserved groove...

Membrane fusion is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. Although membrane fusion is required for separating daughter cells in eukaryotic cytokinesis, the SNARE complexes involved are not known. In plants, membrane vesicles targeted to the cell division plane fuse with one another to form the partitioning membrane, progressing from ...

SNARE complex formation is essential for intracellular membrane fusion. Vesicle-associated (v-) SNARE intertwines with target membrane (t-) SNARE to form a coiled coil that bridges two membranes and facilitates fusion. For the SNARE family involved in neuronal communications, complex formation is tightly regulated by the v-SNARE-membrane interactions. However, it was found using EPR that comple...

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...

Membrane fusion in the secretory pathway is mediated by SNAREs (located on the vesicle membrane [v-SNARE] and the target membrane [t-SNARE]). In all cases examined, t-SNARE function is provided as a three-helix bundle complex containing three approximately 70-amino acid SNARE motifs. One SNARE motif is provided by a syntaxin family member (the t-SNARE heavy chain), and the other two helices are...

Whereas SNARE (soluble N -ethylmaleimide-sensitive factor attachment protein receptor) heptad-repeats are well studied, SNAREs also have upstream N-domains of indeterminate function. The assembly of yeast vacuolar SNAREs into complexes for fusion can be studied in chemically defined reactions. Complementary proteoliposomes bearing a Rab:GTP and either the vacuolar R-SNARE or one of the three in...

Upon Ca2+ influx synaptic vesicles fuse with the plasma membrane and release their neurotransmitter cargo into the synaptic cleft. Key players during this process are the Q-SNAREs syntaxin 1a and SNAP-25 and the R-SNARE synaptobrevin 2. It is thought that these membrane proteins gradually assemble into a tight trans-SNARE complex between vesicular and plasma membrane, ultimately leading to memb...

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are required for intracellular membrane fusion, and are differentially localized throughout the cell. SNAREs on vesicle and target membranes contain "SNARE motifs" which interact to form a four-helix bundle that contributes to the fusion of two membranes. SNARE motif sequences fall into four classes, homologo...