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. Involved in vesicular transport from the late endosomes to the trans-Golgi network. Along with VAMP7, involved in an non-conventional RAB1-dependent traffic route to the cell surface used by KCNIP1 and KCND2. May be involved in increased cytokine secretion associated with cellular senescence. Interacts with distinct SNARE complexes that contain either STX5 or STX6. Interacts with NAPA and, to a lesser extent, with NAPG. Identified in a complex containing STX6, STX12, VAMP4 and VTI1A. Belongs to the VTI1 family.