STX1A
Function
Plays an essential role in hormone and neurotransmitter calcium-dependent exocytosis and endocytosis (PubMed:26635000). Part of the SNARE (Soluble NSF Attachment Receptor) complex composed of SNAP25, STX1A and VAMP2 which mediates the fusion of synaptic vesicles with the presynaptic plasma membrane. STX1A and SNAP25 are localized on the plasma membrane while VAMP2 resides in synaptic vesicles. The pairing of the three SNAREs from the N-terminal SNARE motifs to the C-terminal anchors leads to the formation of the SNARE complex, which brings membranes into close proximity and results in final fusion. Participates in the calcium-dependent regulation of acrosomal exocytosis in sperm (PubMed:23091057). Also plays an important role in the exocytosis of hormones such as insulin or glucagon-like peptide 1 (GLP-1) (By similarity).
Involvement in disease
STX1A is located in the Williams-Beuren syndrome (WBS) critical region. WBS results from a hemizygous deletion of several genes on chromosome 7q11.23, thought to arise as a consequence of unequal crossing over between highly homologous low-copy repeat sequences flanking the deleted region.
Post-translational modifications
Phosphorylated by CK2 (By similarity). Phosphorylation at Ser-188 by DAPK1 significantly decreases its interaction with STXBP1.
Sumoylated, sumoylation is required for regulation of synaptic vesicle endocytosis.
Sequence Similarities
Belongs to the syntaxin family.
Tissue Specificity
Isoform 1
Highly expressed in embryonic spinal cord and ganglia and in adult cerebellum and cerebral cortex.
Isoform 2
Expressed in heart, liver, fat, skeletal muscle, kidney and brain.
Cellular localization
- Cytoplasmic vesicle
- Secretory vesicle
- Synaptic vesicle membrane
- Single-pass type IV membrane protein
- Synapse
- Synaptosome
- Cell membrane
- Colocalizes with KCNB1 at the cell membrane.
- Isoform 2
- Secreted
Alternative names
STX1, STX1A, Syntaxin-1A, Neuron-specific antigen HPC-1