SNAREs, soluble N-ethylmaleimide-sensitive factor-attachment protein receptors, are essential proteins for fusion of cellular membranes. SNAREs localized on opposing membranes assemble to form a trans-SNARE complex, an extended, parallel four alpha-helical bundle that drives membrane fusion (PubMed:23217709, PubMed:25686604, PubMed:28306502). STX17 is a SNARE of the autophagosome involved in autophagy through the direct control of autophagosome membrane fusion with the lysosome membrane (PubMed:23217709, PubMed:25686604, PubMed:28306502, PubMed:28504273). May also play a role in the early secretory pathway where it may maintain the architecture of the endoplasmic reticulum-Golgi intermediate compartment/ERGIC and Golgi and/or regulate transport between the endoplasmic reticulum, the ERGIC and the Golgi (PubMed:21545355). Forms a SNARE complex composed of VAMP8, SNAP29 and STX17 involved in fusion of autophagosome with lysosome (PubMed:23217709, PubMed:25686604). Interacts with VAMP7 and VTI1B (PubMed:23217709). Probably interacts with BET1, SCFD1 and SEC22B (By similarity). Interacts with PTPN2 and ABL1; involved in STX17 phosphorylation (PubMed:23006999). Interacts with COPB1 (By similarity). Interacts with TMED9 and TMED10; the interaction is direct (PubMed:21545355). Interacts with ATG14 (PubMed:25686604). Interacts with RUBCNL/PACER; promoting targeting of RUBCNL/PACER to autophagosome (PubMed:28306502, PubMed:30704899). Interacts with VAMP8, SNAP29, VPS39 and VPS41; these interactions are increased in the absence of TMEM39A (PubMed:31806350, PubMed:33422265). (Microbial infection) The interactions with VAMP8, SNAP29 and VPS41 are decreased in presence of SARS coronavirus-2/SARS-CoV-2 ORF3A protein. Has a hairpin-like insertion into membranes. Localizes to the completed autophagosome membrane upon cell starvation (PubMed:23217709). Phosphorylated at Tyr-157 probably by ABL1. Dephosphorylation by PTPN2; regulates exit from the endoplasmic reticulum (By similarity). (Microbial infection) Cleaved by the L.pneumophila serine protease Lpg1137, impairing endoplasmic reticulum-mitochondria communication, leading to inhibit autophagy. Belongs to the syntaxin family.