Vesicle Transport Through Interaction With t-SNAREs Homolog 1B (VTI1B)

Membrane traffic in eukaryotic cells requires the interaction of a vesicle-associated soluble NSF attachment protein receptor (v-SNARE) on transport vesicles with a t-SNARE on the target membrane. Vti1 is an S. cerevisiae v-SNARE that is essential for viability. Vti1 participates both in Golgi to prevacuolar transport and in traffic to the cis-Golgi. The deduced 232-amino acid human protein contains a C-terminal transmembrane domain and 2 predicted coiled-coil regions. The yeast and human proteins are 29% identical. Expression of human VTI1 in yeast indicated that VTI1 can replace yeast Vti1 in both Golgi transport reactions. Northern blot analysis detected a 1.2-kb VTI1 mRNA in all human tissues tested. Searches of an EST database identified cDNAs encoding a mouse protein with 93% sequence identity to human VTI1.