Sorting of the vesicular GABA transporter to functional vesicle pools by an atypical dileucine-like motif

• Published in: The Journal of neuroscience Vol. 33; no. 26; pp. 10634 - 10646
• Main Authors: Santos, Magda S, Park, C Kevin, Foss, Sarah M, Li, Haiyan, Voglmaier, Susan M
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 26-06-2013
• Subjects: Adaptor Protein Complex 2 - metabolism; Adaptor Protein Complex 3 - metabolism; Amino Acid Motifs; Amino Acid Sequence; Animals; Brain Chemistry - genetics; Cells, Cultured; Data Interpretation, Statistical; DNA Mutational Analysis; Exocytosis - physiology; Fluorescent Antibody Technique; HEK293 Cells; Humans; Lentivirus - genetics; Leucine - physiology; Microscopy, Fluorescence; Molecular Sequence Data; Neurons - metabolism; Point Mutation - genetics; Point Mutation - physiology; Rats; RNA Interference; Signal Transduction - genetics; Signal Transduction - physiology; Synaptic Vesicles - metabolism; Transfection; Vesicular Inhibitory Amino Acid Transport Proteins - metabolism
• ISSN: 0270-6474; 1529-2401; 1529-2401
• DOI: 10.1523/jneurosci.0329-13.2013

Increasing evidence indicates that individual synaptic vesicle proteins may use different signals, endocytic adaptors, and trafficking pathways for sorting to distinct pools of synaptic vesicles. Here, we report the identification of a unique amino acid motif in the vesicular GABA transporter (VGAT) that controls its synaptic localization and activity-dependent recycling. Mutational analysis of this atypical dileucine-like motif in rat VGAT indicates that the transporter recycles by interacting with the clathrin adaptor protein AP-2. However, mutation of a single acidic residue upstream of the dileucine-like motif leads to a shift to an AP-3-dependent trafficking pathway that preferentially targets the transporter to the readily releasable and recycling pool of vesicles. Real-time imaging with a VGAT-pHluorin fusion provides a useful approach to explore how unique sorting sequences target individual proteins to synaptic vesicles with distinct functional properties.