t-SNARE involved in the molecular regulation of neurotransmitter release. May play an important role in the synaptic function of specific neuronal systems. Associates with proteins involved in vesicle docking and membrane fusion. Regulates plasma membrane recycling through its interaction with CENPF. Modulates the gating characteristics of the delayed rectifier voltage-dependent potassium channel KCNB1 in pancreatic beta cells. Part of the SNARE core complex containing SNAP25, VAMP2 and STX1A; this complex binds CPLX1. Found in a complex containing SYT1, SV2B and syntaxin-1 (By similarity). Found in a ternary complex with STX1A and VAMP8 (By similarity). Interacts with HSC70 and with SYT9, forming a complex with DNAJC5 (By similarity). The interaction with SYT9 is inhibited in presence of calcium (By similarity). Isoform 1 and isoform 2 interact with BLOC1S6. Interacts with CENPF. Interacts with EQTN. Interacts with HGS. Interacts with KCNB1 (via N-terminus); reduces the voltage-dependent potassium channel KCNB1 activity in pancreatic beta cells. Interacts with OTOF. Interacts with RIMS1. Interacts with SNAPIN. Interacts with STXBP6. Interacts with TRIM9. Interacts with ZDHHC13 (via ANK repeats). Interacts with ZDHHC17 (via ANK repeats). Associates with the BLOC-1 complex. Interacts with PLCL1 (via C2 domain). Interacts with PRRT2; this interaction may impair the formation of the SNARE complex (By similarity). Interacts with alpha-synuclein/SNCA (By similarity). Interacts with PRPH2 (By similarity). Interacts with ROM1 (By similarity). Interacts with STX3 (By similarity). Membrane association requires palmitoylation. Expressed throughout cytoplasm, concentrating at the perinuclear region. Colocalizes with KCNB1 at the cell membrane (By similarity). Colocalizes with PLCL1 at the cell membrane (By similarity). The N-terminus is blocked. Belongs to the SNAP-25 family.