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Targeting of the 67-kDa isoform of glutamic acid decarboxylase to intracellular organelles is mediated by its interaction with the NH2- terminal region of the 65-kDa isoform of glutamic acid decarboxylase

Dirkx, R. ; Thomas, A. ; Li, L. ; Lernmark, A. LU orcid ; Sherwin, R. S. ; De Camilli, P. and Solimena, M. (1995) In Journal of Biological Chemistry 270(5). p.2241-2246
Abstract

The two isoforms of glutamic acid decarboxylase (GAD), GAD67 and GAD65, synthesize the neurotransmitter γ-aminobutyric acid in neurons and pancreatic β-cells. Previous studies suggest that GAD67 is a soluble cytosolic protein, whereas GAD65 is membrane-associated. Here we study the intracellular distribution of GAD67 in neurons, pancreatic β-cells, and fibroblasts transfected either with GAD65 and GAD67 together or with GAD67 alone. Neuronal GAD67 is partially recovered with GAD65 in membrane- containing pellet fractions and Triton X-114 detergent phases. The two proteins coimmunoprecipitate from extracts of brain and GAD65-GAD67 cotransfected fibroblasts, but not when extracts of GAD65 and GAD67 transfected fibroblasts were mixed and... (More)

The two isoforms of glutamic acid decarboxylase (GAD), GAD67 and GAD65, synthesize the neurotransmitter γ-aminobutyric acid in neurons and pancreatic β-cells. Previous studies suggest that GAD67 is a soluble cytosolic protein, whereas GAD65 is membrane-associated. Here we study the intracellular distribution of GAD67 in neurons, pancreatic β-cells, and fibroblasts transfected either with GAD65 and GAD67 together or with GAD67 alone. Neuronal GAD67 is partially recovered with GAD65 in membrane- containing pellet fractions and Triton X-114 detergent phases. The two proteins coimmunoprecipitate from extracts of brain and GAD65-GAD67 cotransfected fibroblasts, but not when extracts of GAD65 and GAD67 transfected fibroblasts were mixed and used as a stating material for immunoprecipitation. GAD67 is concentrated in the Gorgi complex region in GAD65-GAD67 cotransfected fibroblasts, but not in fibroblasts transfected with GAD67 alone. A pool of neuronal GAD67 colocalizes with GAD65 in the Golgi complex region and in many synapses. The two proteins also colocalize in the perinuclear region of some pancreatic ̄-cells. GAD67 interacts with the NH2-terminal region of GAD65, even in the absence of palmitoylation of this region of GAD65. Taken together, our results indicate that GAD65-GAD67 association occurs in vivo and is required for the targeting of GAD67 to membranes.

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author
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publishing date
type
Contribution to journal
publication status
published
in
Journal of Biological Chemistry
volume
270
issue
5
pages
2241 - 2246
publisher
American Society for Biochemistry and Molecular Biology
external identifiers
  • pmid:7836456
  • scopus:0028929053
ISSN
0021-9258
DOI
10.1074/jbc.270.5.2241
language
English
LU publication?
no
id
2a6eee77-902c-426b-9c10-b4a9537c373c
date added to LUP
2019-09-11 08:56:10
date last changed
2024-03-13 08:27:27
@article{2a6eee77-902c-426b-9c10-b4a9537c373c,
  abstract     = {{<p>The two isoforms of glutamic acid decarboxylase (GAD), GAD67 and GAD65, synthesize the neurotransmitter γ-aminobutyric acid in neurons and pancreatic β-cells. Previous studies suggest that GAD67 is a soluble cytosolic protein, whereas GAD65 is membrane-associated. Here we study the intracellular distribution of GAD67 in neurons, pancreatic β-cells, and fibroblasts transfected either with GAD65 and GAD67 together or with GAD67 alone. Neuronal GAD67 is partially recovered with GAD65 in membrane- containing pellet fractions and Triton X-114 detergent phases. The two proteins coimmunoprecipitate from extracts of brain and GAD65-GAD67 cotransfected fibroblasts, but not when extracts of GAD65 and GAD67 transfected fibroblasts were mixed and used as a stating material for immunoprecipitation. GAD67 is concentrated in the Gorgi complex region in GAD65-GAD67 cotransfected fibroblasts, but not in fibroblasts transfected with GAD67 alone. A pool of neuronal GAD67 colocalizes with GAD65 in the Golgi complex region and in many synapses. The two proteins also colocalize in the perinuclear region of some pancreatic ̄-cells. GAD67 interacts with the NH<sub>2</sub>-terminal region of GAD65, even in the absence of palmitoylation of this region of GAD65. Taken together, our results indicate that GAD65-GAD67 association occurs in vivo and is required for the targeting of GAD67 to membranes.</p>}},
  author       = {{Dirkx, R. and Thomas, A. and Li, L. and Lernmark, A. and Sherwin, R. S. and De Camilli, P. and Solimena, M.}},
  issn         = {{0021-9258}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{5}},
  pages        = {{2241--2246}},
  publisher    = {{American Society for Biochemistry and Molecular Biology}},
  series       = {{Journal of Biological Chemistry}},
  title        = {{Targeting of the 67-kDa isoform of glutamic acid decarboxylase to intracellular organelles is mediated by its interaction with the NH<sub>2</sub>- terminal region of the 65-kDa isoform of glutamic acid decarboxylase}},
  url          = {{http://dx.doi.org/10.1074/jbc.270.5.2241}},
  doi          = {{10.1074/jbc.270.5.2241}},
  volume       = {{270}},
  year         = {{1995}},
}