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Cannabinoid receptor interacting protein suppresses agonist‐driven CB 1 receptor internalization and regulates receptor replenishment in an agonist‐biased manner
Author(s) -
Blume Lawrence C.,
LeoneKabler Sandra,
Luessen Deborah J.,
Marrs Glen S.,
Lyons Erica,
Bass Caroline E.,
Chen Rong,
Selley Dana E.,
Howlett Allyn C.
Publication year - 2016
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.13767
Subject(s) - receptor , agonist , cycloheximide , internalization , cannabinoid receptor , microbiology and biotechnology , g protein , cannabinoid receptor agonists , signal transduction , biology , chemistry , biochemistry , protein biosynthesis
Cannabinoid receptor interacting protein 1a ( CRIP 1a) 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 CRIP 1a 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 N18 TG 2, which endogenously expresses both CB 1 R and CRIP 1a, and exhibits a well‐characterized endocannabinoid signaling system. We developed stable CRIP 1a‐over‐expressing and CRIP 1a‐si RNA ‐silenced knockdown clones to investigate gene dose effects of CRIP 1a on CB 1 R plasma membrane expression. Results indicate that CP 55940 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 CRIP 1a over‐expression. CP 55940‐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 CRIP 1a knockdown cells. Changes in CRIP 1a 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 CRIP 1a 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.