V-SNARE that mediates vesicle transport pathways through interactions with t-SNAREs on the target membrane. These interactions are proposed to mediate aspects of the specificity of vesicle trafficking and to promote fusion of the lipid bilayers. May be concerned with increased secretion of cytokines associated with cellular senescence. Forms a SNARE complex with STX7, STX8 and VAMP8 which functions in the homotypic fusion of late endosomes. Component of the SNARE complex composed of STX7, STX8, VAMP7 and VIT1B that is required for heterotypic fusion of late endosomes with lysosomes (By similarity). May interact with STX17. Interacts with CLINT1 (By similarity). Belongs to the VTI1 family.