Neuroscience 2005 Abstract
| Presentation Number: | 727.15 |
|---|---|
| Abstract Title: | Functional diversity of p16 and its variants. |
| Authors: |
Tu, S.*1
; Shin, Y.1
; Zago, W. M.1
; Lipton, S. A.1
; Tong, G.1
; Nakanishi, N.1
1Ctr Neurosci & Aging, The Burnham Inst., La Jolla, CA |
| Primary Theme and Topics |
Neural Excitability, Synapses, and Glia: Cellular Mechanisms - Synaptic Transmission -- Postsynaptic organization and structure |
| Secondary Theme and Topics | Neural Excitability, Synapses, and Glia: Cellular Mechanisms<br />- Synaptic Plasticity<br />-- Spines and structural plasticity |
| Session: |
727. Postsynaptic Organization and Function: PSD Composition Poster |
| Presentation Time: | Tuesday, November 15, 2005 3:00 PM-4:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # F42 |
| Keywords: | NR3A, NMDA, PSD-95, dendritic spine |
P16 was first identified as a gene that was upregulated in mice deficient for NR3A (a novel NMDA receptor subunit; Tu et al., 2003, SfN abstract 796.2). We showed previously that forced expression of p16 in cultured hippocampal neurons resulted in increased PSD-95 clustering and enhanced dendritic-spine density. In the current study, we examined the functional diversity among p16 homologues. p16 is a member of a large gene family, and its variants show sequence diversity at the C-terminus. Due to these variations, some p16 members are predicted to bind PDZ domain-containing proteins, such as PSD-95, while others do not. We first tested this idea by co-expressing p16 or select variants together with PSD-95 in COS cells. In these experiments, variations at the C-termini among the p16 variants produced differential binding to PDZ domains. We next examined two p16 variants (p16-svi, which binds to PSD-95, and p16-svk, which does not) for their ability to cluster PSD-95 and increase dendritic spine density. We transduced fusion proteins between p16 variants and EGFP (referred to as EGFP-p16-svi and EGFP-p16-svk) into cultured neurons. As predicted from each variant’s ability to bind PSD-95, EGFP-p16-svi closely co-localized with PSD-95 in dendritic spines of transfected neurons. In contrast, EGFP-p16-svk did not co-localize with PSD-95. Instead, it appeared to appose PSD-95 within dendritic spines. Intriguingly, upon forced expression, both EGFP-p16-svi and –svk increased the density of PSD-95 clusters and dendritic spines. However, the effects of EGFP-p16-svi on these increases were significantly larger than those of EGFP-p16-svk. The exact mechanism(s) by which these two variants exert their actions on dendritic spine physiology are currently under investigation.
Supported by NIH P01 HD29587 and R01 EY05477
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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