title: Role of glutamate decarboxylase (GAD) isoform, GAD65, in GABA synthesis and transport into synaptic vesicles-Evidence from GAD65-knockout mice studies.
abstract: In GAD65-knockout mice, lack of GAD65 expression was confirmed. The expression level of vesicular GABA transporter (VGAT) was upregulated, and no change in the synaptic vesicles (SV)-associated GAD67 was found. GAD65(-/-) SV transported cytosolic GABA much more efficiently than that of the wild type, further supporting our model that there is a structural and functional coupling between GABA synthesis and packaging into SV. Both full-length and truncated forms of GAD65 could bind to GABAergic SV, indicating the N-terminus is not required for the anchoring of GAD65 to SV. Although both GAD65(-/-) SV reconstituted with either GAD65 or GAD67 could synthesize GABA from [3H] glutamate and transport this newly synthesized GABA into SV, the combined evidence suggests that GAD65 plays a major role in GABA transmission in normal physiological condition. However, GAD67 could serve this role under some pathological conditions.
authors.affiliation: Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA.
authors.forename: Heng
authors.initials: H
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Jin
authors.forename: Chandana
authors.initials: C
authors.lastname: Buddhala
authors.forename: Gregory
authors.initials: G
authors.lastname: Osterhaus
authors.forename: Eric
authors.initials: E
authors.lastname: Cohen
authors.forename: Hong
authors.initials: H
authors.lastname: Jin
authors.forename: Jianning
authors.initials: J
authors.lastname: Wei
authors.forename: Kathleen
authors.initials: K
authors.lastname: Davis
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Obata
authors.forename: Jang-Yen
authors.initials: JY
authors.lastname: Wu
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000235:genetics*; D005968:Glutamate Decarboxylase / Q000172:deficiency / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism; D007527:Isoenzymes / Q000172:deficiency / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D021381:Protein Transport / Q000235:genetics; D013572:Synaptic Vesicles / Q000235:genetics / Q000502:physiology*; D014316:Tritium / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; D014316:Tritium; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2