Involved in acetylcholine transport into synaptic vesicles. Interacts with SEC14L1. High expression in all major cholinergic cell groups, including peripheral postganglionic parasympathetic cells, preganglionic sympathetic and parasympathetic cells, ventral spinal cord and brainstem motoneurons, cell groups in the basal forebrain, the habenula and the corpus striatum. Weakly expressed in the cortex and hippocampus. Belongs to the major facilitator superfamily. Vesicular transporter family.