GLAST stability and activity are enhanced by interaction with the PDZ scaffold NHERF-2

NEUROSCIENCE LETTERS

卷:487

Article

Yun, C. Chris²  Hall, Randy A.¹ 

[1] Emory Univ, Rollins Res Ctr, Sch Med, Dept Pharmacol, Atlanta, GA 30322 USA

[2] Emory Univ, Dept Med, Sch Med, Atlanta, GA 30322 USA

关键词: Glia;    Astrocyte;    Neurodegeneration;    Excitatory amino acid;    Transporter;    Receptor;   

DOI  :  10.1016/j.neulet.2010.04.043

来源: Elsevier

【 摘 要 】

The astrocytic glutamate transporter GLAST (also known as EAAT1) is a key regulator of extracellular glutamate levels in many regions of vertebrate brains. To identify novel interacting partners that might regulate the localization and function of GLAST in astrocytes, we screened the transporter's C-terminus (GLAST-CT) against a proteomic array of 96 different PDZ domains. The GLAST-CT robustly and specifically interacted with PDZ domains from two related scaffolding proteins, the Na+/H+ exchanger regulatory factors 1 and 2 (NHERF-1 and NHERF-2). Studies on cultured rat cortical astrocytes revealed that these cells are highly enriched in NHERF-2 relative to NHERF-1. Endogenous GLAST and NHERF-2 from cultured astrocytes were found to robustly co-immunoprecipitate, and further co-immunoprecipitation studies on mutant versions of GLAST expressed in transfected cells revealed the GLAST/NHERF-2 interaction to be dependent on the last amino acid of the GLAST-CT. Knockdown of endogenous NHERF-2 in astrocytes via siRNA treatment resulted in a significant reduction in GLAST activity, which corresponded to significantly reduced total expression of GLAST protein and reduced half-life of GLAST, as assessed in pulse-chase metabolic labeling studies. These findings reveal that NHERF-2 can interact with GLAST in astrocytes to enhance GLAST stability and activity. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

【 授权许可】

Free