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 suppresses agonist-driven CB sub(1) receptor internalization and regulates receptor replenishment in an agonist-biased manner

Ist Teil von

• Journal of neurochemistry, 2016-11, Vol.139 (3), p.396-407

Erscheinungsjahr

2016

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Cannabinoid receptor interacting protein 1a (CRIP1a) is a CB sub(1) receptor (CB sub(1)R) distal C-terminus-associated protein that modulates CB sub(1)R signaling via G proteins, and CB sub(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 sub(1)R plasma membrane trafficking. To follow the effects of agonists and antagonists on cell surface CB sub(1)Rs, we utilized the genetically homogeneous cloned neuronal cell line N18TG2, which endogenously expresses both CB sub(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 sub(1)R plasma membrane expression. Results indicate that CP55940 or WIN55212-2 (10 nM, 5 min) reduced cell surface CB sub(1)R by a dynamin- and clathrin-dependent process, and this was attenuated by CRIP1a over-expression. CP55940-mediated cell surface CB sub(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 sub(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 sub(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 sub(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. The CB sub(1)R-interacting protein CRIP1a functions to differentially modulate agonist-promoted versus non-agonist-mediated CB sub(1)R internalization and cell surface equilibrium. Association of CRIP1a with the CB sub(1)R precludes agonist-driven internalization via a mechanism involving beta -arrestin, clathrin and dynamin. CRIP1a also functions to fine-tune CB sub(1)R cell surface levels through delivery of newly synthesized CB sub(1)R receptors to the plasma membrane.