Umesh, Anita and Cohen, Bruce N. and Ross, Linda S. and Gill, Sarjeet S. (2003) Functional characterization of a glutamate/aspartate transporter from the mosquito Aedes aegypti. Journal of Experimental Biology, 206 (13). pp. 2241-2255. ISSN 0022-0949. http://resolver.caltech.edu/CaltechAUTHORS:20111010-145028790
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Glutamate elicits a variety of effects in insects, including inhibitory and excitatory signals at both neuromuscular junctions and brain. Insect glutamatergic neurotransmission has been studied in great depth especially from the standpoint of the receptor-mediated effects, but the molecular mechanisms involved in the termination of the numerous glutamatergic signals have only recently begun to receive attention. In vertebrates, glutamatergic signals are terminated by Na^+/K^+-dependent high-affinity excitatory amino acid transporters (EAAT), which have been cloned and characterized extensively. Cloning and characterization of a few insect homologues have followed, but functional information for these homologues is still limited. Here we report a study conducted on a cloned mosquito EAAT homologue isolated from the vector of the dengue virus, Aedes aegypti. The deduced amino acid sequence of the protein, AeaEAAT, exhibits 40–50% identity with mammalian EAATs, and 45–50% identity to other insect EAATs characterized thus far. It transports l-glutamate as well as l- and d-aspartate with high affinity in the micromolar range, and demonstrates a substrate-elicited anion conductance when heterologously expressed in Xenopus laevis oocytes, as found with mammalian homologues. Analysis of the spatial distribution of the protein demonstrates high expression levels in the adult thorax, which is mostly observed in the thoracic ganglia. Together, the work presented here provides a thorough examination of the role played by glutamate transport in Ae. aegypti.
|Additional Information:||© 2003 The Company of Biologists Ltd. Accepted 3 April 2003. We thank Drs V. Filippov, Y. Park, C. S. Chiu, and M. E. Adams for valuable discussions throughout the course of this work; Dr Y. Zhao for expert technical guidance; Drs V. Filippov, M. L. Patrick and Ms H. R. Sanders for critically perusing the manuscript; and Ms A. Soderini-Coviella for maintaining the Ae. aegypti colony and help with dissections. This research was funded by grants AI 48049 to S.S.G. and a University of California Dissertation Research Grant to A.U.|
|Subject Keywords:||glutamate/aspartate transporter; mosquito; Aedes aegypti; neurotransmitter; amino acid; electrophysiology; localization|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||11 Oct 2011 21:41|
|Last Modified:||26 Dec 2012 14:15|
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