|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online 3 May 2006
doi: 10.1242/dev.02399
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Center for Molecular Genetics, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0368, USA.
* Author for correspondence (e-mail: wloomis{at}ucsd.edu)
Accepted 7 April 2006
When prespore cells approach the top of the stalk in a Dictyostelium fruiting body, they rapidly encapsulate in response to the signalling peptide SDF-2. Glutamate decarboxylase, the product of the gadA gene, generates GABA from glutamate. gadA is expressed exclusively in prespore cells late in development. We have found that GABA induces the release of the precursor of SDF-2, AcbA, from prespore cells. GABA also induces exposure of the protease domain of TagC on the surface of prestalk cells where it can convert AcbA to SDF-2. The receptor for GABA in Dictyostelium, GrlE, is a seven-transmembrane G-protein-coupled receptor that is most similar to GABAB receptors. The signal transduction pathway from GABA/GrlE appears to be mediated by PI3 kinase and the PKB-related protein kinase PkbR1. Glutamate acts as a competitive inhibitor of GABA functions in Dictyostelium and is also able to inhibit induction of sporulation by SDF-2. The signal transduction pathway from SDF-2 is independent of the GABA/glutamate signal transduction pathway, but the two appear to converge to control release of AcbA and exposure of TagC protease. These results indicate that GABA is not only a neurotransmitter but also an ancient intercellular signal.
Key words: gadA, GrlE, SDF-2, Sporulation, GPCR
Related articles in Development:
This article has been cited by other articles:
![]() |
N. Van Driessche, H. Alexander, J. Min, A. Kuspa, S. Alexander, and G. Shaulsky Global transcriptional responses to cisplatin in Dictyostelium discoideum identify potential drug targets PNAS, September 25, 2007; 104(39): 15406 - 15411. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. G. Forde and P. J. Lea Glutamate in plants: metabolism, regulation, and signalling J. Exp. Bot., July 1, 2007; 58(9): 2339 - 2358. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Cabral, C. Anjard, W. F. Loomis, and A. Kuspa Genetic Evidence that the Acyl Coenzyme A Binding Protein AcbA and the Serine Protease/ABC Transporter TagA Function Together in Dictyostelium discoideum Cell Differentiation Eukaryot. Cell, December 1, 2006; 5(12): 2024 - 2032. [Abstract] [Full Text] [PDF] |
||||