The function of VTI1B (vesicle transport through interaction with t-SNAREs 1B, Ensembl gene identifier ENSG00000100568) is as follows. SNAREs (soluble N-ethylmaleimide-sensitive factor-attachment protein receptors) are essential proteins for intracellular membrane fusion. SNAREs localized on opposing membranes assemble to form a trans-SNARE complex, an extended, parallel four-helix bundle whose assembly releases energy that drives membrane fusion. The core SNARE complex typically consists of four alpha-helical domains, three from target membrane SNAREs (t-SNAREs) and one from a vesicle SNARE (v- SNARE) (PubMed:21388490, PubMed:23217709). On late endosomes, regulates trafficking from late endosomes to the lysosome (Probable). {ECO:0000269|PubMed:21388490, ECO:0000269|PubMed:23217709, ECO:0000305|PubMed:21388490}.