Neuroscience 2004 Abstract
| Presentation Number: | 280.8 |
|---|---|
| Abstract Title: | Ubiquitination mechanisms in support of norepinephrine transporter regulation. |
| Authors: |
Sung, U.*1,2
; Han, Q.1,2
; Link, A. J.3
; Blakely, R. D.1,2
1Ctr Mol Neurosci, Vanderbilt Uni, Nashville, TN 2Depts. Pharmacol, Vanderbilt Uni, Nashville, TN 3Microbio and Immunol, Vanderbilt Uni, Nashville, TN |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Transporters -- Monoamines, GABA, etc. |
| Session: |
280. Dopamine Transporter II Poster |
| Presentation Time: | Sunday, October 24, 2004 4:00 PM-5:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # G37 |
| Keywords: | norepinephrine transporter, proteomics, ubiquitin, proteasome |
The norepinephrine transporter (NET) terminates noradrenergic signals by clearing released NE from extracellular synapses. Stimulation of presynaptic receptors regulates activity of NET via second messengers and kinase/ phosphatase linked pathways that modulate surface trafficking and alter catalytic activity. Stimulation of M3 acetylcholine receptors induces internalization of NET via protein kinase C dependent pathways (Apparsundaram et al. 1998). Further clarification of these pathways may suggest candidates for novel therapeutics as well as identify mechanisms that may be altered in disease states. Recently, we conducted immunoprecipitation (IP) of NET from a stably transfected neuroblastoma (CAD cells) and analyzed the proteins co-immunoprecipitated with NET by LC-MS/MS (Sung et al., 2003, SFN). In the analysis, we identified multiple peptides related to ubiquitin (Ub) system among other NET associated proteins. These proteins include the E3 ligase Nedd-4, E2 conjugating and E1 activating enzymes, suggesting an interaction of NET or NET-associated proteins with complexes containing Ub enzymes and the potential for regulation of NET by ubiquitination. Co-transfected hNET and Ub followed by reciprocal IP indicates that NET may be in association with Ub-tagged complexes or a direct target for ubiquitination. Application of phorbol ester or stimulation of M3 receptors by methacholine rapidly increased recovery of NET/Ub complexes. Treatment of transfected CAD cells with a proteasomal inhibitor triggers accumulation of NET protein, suggesting NET as a target for Ub-mediated proteasomal degradation. Our findings support a role for ubiquitination of NET and/or NET associated proteins in the regulated trafficking and turnover of transporter proteins. Current studies seek to identify targets of Ub modification as well as elucidate mechanisms by which Ub participate in NET regulation. This work is supported by NIH award MH58921 to R.D.B.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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