Journal article
Calmodulin binding to glutamate decarboxylase is required for regulation of glutamate and GABA metabolism and normal development in plants
EMBO Journal, Vol.15(12), pp.2988-2996
01/Jun/1996
Abstract
Glutamate decarboxylase (GAD) catalyzes the decarboxylation of glutamate to CO2 and gamma-aminobutyrate (GABA). GAD is ubiquitous in prokaryotes and eukaryotes, but only plant GAD has been shown to bind calmodulin (CaM). Here, we assess the role of the GAD CaM-binding domain in vivo. Transgenic tobacco plants expressing a mutant petunia GAD lacking the CaM-binding domain (GAD Delta C plants) exhibit severe morphological abnormalities, such as short stems, in which cortex parenchyma cells fail to elongate, associated with extremely high GABA and low glutamate levels. The morphology of transgenic plants expressing the full-length GAD (GAD plants) is indistinguishable from that of wild-type (WT) plants, In WT and GAD plant extracts, GAD activity is inhibited by EGTA and by the CaM antagonist trifluoperazine, and is associated with a CaM-containing protein complex of similar to 500 kDa, In contrast, GAD Delta C plants lack normal GAD complexes, and GAD activity in their extracts is not affected by EGTA and trifluoperazine. We conclude that CaM binding to GAD is essential for the regulation of GABA and glutamate metabolism, and that regulation of GAD activity is necessary for normal plant development. This study is the first to demonstrate an in vivo function for CaM binding to a target protein in plants.
Details
- Title
- Calmodulin binding to glutamate decarboxylase is required for regulation of glutamate and GABA metabolism and normal development in plants
- Creators
- G Baum (null) - The Weizmann Institute of ScienceS Lev-Yadun (null) - The Weizmann Institute of ScienceY Fridmann (null) - The Weizmann Institute of ScienceT Arazi (null) - The Weizmann Institute of ScienceH Katsnelson (null) - The Weizmann Institute of ScienceM Zik (null) - The Weizmann Institute of ScienceH Fromm (Corresponding Author) - The Weizmann Institute of Science
- Resource Type
- Journal article
- Publication Details
- EMBO Journal, Vol.15(12), pp.2988-2996; 01/Jun/1996
- Number of pages
- 9
- Language
- English
- DOI
- https://doi.org/10.1002/j.1460-2075.1996.tb00662.x
- Grant note
- We thank D.Dolev for excellent technical assistance in the preparation and maintenance of transgenic plants, and Professors E.Galun, J.Gressel and G.Galili for critically reading the manuscript. G.B. was the recipient of a Levi Eshkol Graduate Fellowship from the Ministry of Science & the Arts, Israel. This work was supported by grants to H.F. from the United States-IsraelBinational Agricultural Research and Development Fund, from the Wolfson Research Awardsadministered by the Israel Academy of Sciences and Humanities, and by a grant from the Israel Ministry of Science & the Arts and the Gesellschaft fir Biotechnologische Forschung, GBF Braunschweig, Germany. H.E. is the Incumbent of the Abraham and Jenny Fialkow Career Development Chair in Biology.
- Scientific Unit
- The Weizmann Institute of Science
- Record Identifier
- 993266005303596
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