STX4 is a plasma membrane t-SNARE protein that mediates transport vesicle docking and membrane fusion events critical for cellular trafficking. As a SNARE complex component, STX4 partners with SNAP23 and VAMP proteins to regulate diverse membrane fusion processes, including GLUT4 translocation to the cell surface and synaptic vesicle docking 1. STX4 participates in secretory autophagy, where autophagosomes fuse with the plasma membrane for cytokine secretion; TRIM16-regulated STX4 colocalizes with LC3B and IL6 in cancer-associated fibroblasts to mediate autophagy-dependent IL6 secretion 2. STX4 also functions in autophagic proteostasis of α-synuclein; knockdown impairs lysosomal function and α-synuclein clearance relevant to Parkinson's disease 3. Beyond neurodegeneration, STX4 influences childhood asthma susceptibility through CD4+ and CD8+ T cell-mediated immune mechanisms, with DNA methylation regulating its expression 4. In ovarian cancer, STX4 promotes tumor progression via EMT/MMP2/CCND1 pathways, with silencing reducing proliferation and invasion 5. STX4 dysregulation appears in Parkinson's disease proteogenomic networks 6 and associates with lipid metabolism through adipose-brain communication 7. Mutations cause autosomal recessive deafness, highlighting its role in auditory function.