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Carboxypeptidase E cytoplasmic tail mediates localization of synaptic vesicles to the pre‐active zone in hypothalamic pre‐synaptic terminals
Author(s) -
Lou Hong,
Park Joshua J.,
Cawley Niamh X.,
Sarcon Annahita,
Sun Lei,
Adams Tiffany,
Peng Loh Yoke
Publication year - 2010
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2010.06820.x
Subject(s) - active zone , synaptic vesicle , microbiology and biotechnology , synaptophysin , biology , cytoplasm , synapse , glutamate receptor , chemistry , biophysics , vesicle , neuroscience , biochemistry , membrane , immunology , immunohistochemistry , receptor
J. Neurochem. (2010) 114 , 886–896. Abstract How synaptic vesicles (SVs) are localized to the pre‐active zone (5–200 nm beneath the active zone) in the nerve terminal, which may represent the slow response SV pool, is not fully understood. Electron microscopy revealed the number of SVs located in the pre‐active zone, was significantly decreased in hypothalamic neurons of carboxypeptidase E knockout (CPE‐KO) mice compared with wild‐type mice. Additionally, we found K + ‐stimulated glutamate secretion from hypothalamic embryonic neurons was impaired in CPE‐KO mice. Biochemical studies indicate that SVs from the hypothalamus of wild‐type mice and synaptic‐like microvesicles from PC12 cells contain a transmembrane form of CPE, with a cytoplasmic tail (CPE C10 ), maybe involved in synaptic function. Yeast two‐hybrid and pull‐down experiments showed that the CPE cytoplasmic tail interacted with γ‐adducin, which binds actin enriched at the nerve terminal. Total internal reflective fluorescence (TIRF) microscopy using PC12 cells as a model showed that expression of GFP‐CPE C15 reduced the steady‐state level of synaptophysin‐mRFP containing synaptic‐like microvesicles accumulated in the area within 200 nm from the sub‐plasma membrane (TIRF zone). Our findings identify the CPE cytoplasmic tail, as a new mediator for the localization of SVs in the actin‐rich pre‐active zone in hypothalamic neurons and the TIRF zone of PC12 cells.