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Dileucine Motif Is Sufficient for Internalization and Synaptic Vesicle Targeting of Vesicular Acetylcholine Transporter
Author(s) -
Colgan Lesley,
Liu Hao,
Huang Steven Y.,
Liu YongJian
Publication year - 2007
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2007.00555.x
Subject(s) - vesicular acetylcholine transporter , internalization , biology , microbiology and biotechnology , synaptic vesicle , vesicular transport protein , colocalization , immunoprecipitation , vesicle , protein sorting signals , endosome , sequence motif , transport protein , cholinergic , peptide sequence , biochemistry , neuroscience , signal peptide , gene , membrane , cell , intracellular , choline acetyltransferase
Efficient cholinergic transmission requires accurate targeting of vesicular acetylcholine transporter (VAChT) to synaptic vesicles (SVs). However, the signals that regulate this vesicular targeting are not well characterized. Although previous studies suggest that the C‐terminus of the transporter is required for its SV targeting, it is not clear whether this region is sufficient for this process. Furthermore, a synaptic vesicle‐targeting motif (SVTM) within this sequence remains to be identified. Here we use a chimeric protein, TacA, between an unrelated plasma membrane protein, Tac, and the C‐terminus of VAChT to demonstrate the sufficiency of the C‐terminus for targeting to synaptic vesicle‐like vesicles (SVLVs) in PC12 cells. TacA shows colocalization and cosedimentation with the SV marker synaptophysin. Deletion mutation analysis of TacA demonstrates that a short, dileucine motif‐containing sequence is required and sufficient to direct this targeting. Dialanine mutation analysis within this sequence suggests indistinguishable signals for both internalization and SV sorting. Using additional chimeras as controls, we confirm the specificity of this region for SVLVs targeting. Therefore, we suggest that the dileucine‐containing motif is sufficient as a dual signal for both internalization and SV targeting during VAChT trafficking.