Details

Autor(en) / Beteiligte

• Blume, Lawrence C.
• Leone-Kabler, Sandra
• Luessen, Deborah J.
• Marrs, Glen S.
• Lyons, Erica
• Bass, Caroline E.
• Chen, Rong
• Selley, Dana E.
• Howlett, Allyn C.

Titel

Cannabinoid receptor interacting protein suppress agonist–driven CB1 receptor internalization and regulates receptor replenishment in an agonist–biased manner

Ist Teil von

• Journal of neurochemistry, 2016-09, Vol.139 (3), p.396-407

Erscheinungsjahr

2016

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Cannabinoid receptor interacting protein 1a (CRIP1a) is a CB 1 receptor (CB 1 R) distal C-terminus-associated protein that modulates CB 1 R signaling via G proteins, and CB 1 R down-regulation but not desensitization ( Blume et al . [2015] Cell Signal. , 27, 716–726; Smith et al . [2015] Mol. Pharmacol. , 87, 747–765). In this study, we determined the involvement of CRIP1a in CB 1 R plasma membrane trafficking. To follow the effects of agonists and antagonists on cell surface CB 1 Rs, we utilized the genetically homogeneous cloned neuronal cell line N18TG2, which endogenously expresses both CB 1 R and CRIP1a, and exhibits a well-characterized endocannabinoid signaling system. We developed stable CRIP1a-over-expressing and CRIP1a-siRNA-silenced knockdown clones to investigate gene dose effects of CRIP1a on CB 1 R plasma membrane expression. Results indicate that CP55940 or WIN55212-2 (10 nM, 5 min) reduced cell surface CB 1 R by a dynamin- and clathrin-dependent process, and this was attenuated by CRIP1a over-expression. CP55940-mediated cell surface CB 1 R loss was followed by a cycloheximide-sensitive recovery of surface receptors (30–120 min), suggesting the requirement for new protein synthesis. In contrast, WIN55212-2-mediated cell surface CB 1 Rs recovered only in CRIP1a knockdown cells. Changes in CRIP1a expression levels did not affect a transient rimonabant (10 nM)-mediated increase in cell surface CB 1 Rs, which is postulated to be as a result of rimonabant effects on ‘non-agonist-driven’ internalization. These studies demonstrate a novel role for CRIP1a in agonist-driven CB 1 R cell surface regulation postulated to occur by two mechanisms: 1) attenuating internalization that is agonist-mediated, but not that in the absence of exogenous agonists, and 2) biased agonist-dependent trafficking of de novo synthesized receptor to the cell surface.