The proposed studies will investigate the mechanisms by which agonist-selectivity in G protein activation allows selection of differential therapeutically-relevant signal transduction pathways. Working hypotheses begin with a model of sequential steps of ligand docking to the inactive receptor-GGDP complex; agonist-induced conformational change in the receptor and concomitant conformational change in the G protein resulting in its activation (GDP/GTP exchange); G-alpha or G-betagamma regulation of effectors leading to signal transduction pathway activation. Studies previously supported by this grant demonstrated the G protein selectivity that CB, intracellular domains prefer (IL4 with G-alpha0 or G-alphai3, and IL3 with G-alphai1 or G-alphai2). We further demonstrated that agonists of distinct chemical classes influence these different receptor-G protein linteractions. We propose the testable hypothesis that chemically distinct CB1 ligands and Iphosphorylation modifications define which signal transduction pathway(s) are activated.
In Aim 1, we continue to define the types of G proteins that interact with the CB1 receptor, and investigate the necessary receptor domains, and the influence of agonists and phosphorylation.
In Aim 2, we investigate the CB 1 receptor intracellular surface structure that interfaces with G proteins and assess modifications imposed by post-translational events, in collaboration with structural biology studies by Jason Burgess at RTI, Intl., Sudha Cowsik, and John (Joong-Youn) Shim.
In Aim 3, we assess the potential for agonist-directed signal transduction pathway selection: adenylyl cyclase inhibition, MAPK activation, Ca 2v regulation, and NO production, which represent a diversity in potential signal transduction pathway mechanisms. The opportunity for drug design of agonists to facilitate selective receptor-G protein mediated signal transduction pathways may allow stimulation of neuronal cells in brain regions that regulate beneficial effects such as pain relief and alleviation of spasticity and motor dysfunction of neurodegenerative diseases, versus neurons in brain regions that promote untoward responses such as cognitive dysfunction and memory dysregulation.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA003690-22
Application #
7029701
Study Section
Molecular Neuropharmacology and Signaling Study Section (MNPS)
Program Officer
Rapaka, Rao
Project Start
1984-09-01
Project End
2006-10-13
Budget Start
2006-04-01
Budget End
2006-10-13
Support Year
22
Fiscal Year
2006
Total Cost
$99,650
Indirect Cost
Name
North Carolina Central University
Department
Type
Organized Research Units
DUNS #
783691801
City
Durham
State
NC
Country
United States
Zip Code
27707
Eldeeb, Khalil; Leone-Kabler, Sandra; Howlett, Allyn C (2017) Mouse Neuroblastoma CB1 Cannabinoid Receptor-Stimulated [35S]GTP?S Binding: Total and Antibody-Targeted G? Protein-Specific Scintillation Proximity Assays. Methods Enzymol 593:1-21
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Eldeeb, Khalil; Leone-Kabler, Sandra; Howlett, Allyn C (2016) CB1 cannabinoid receptor-mediated increases in cyclic AMP accumulation are correlated with reduced Gi/o function. J Basic Clin Physiol Pharmacol 27:311-22
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Conner-Kerr, Teresa; Malpass, Gloria; Steele, Arhalia et al. (2015) Effects of 35 kHz, low-frequency ultrasound application in vitro on human fibroblast morphology and migration patterns. Ostomy Wound Manage 61:34-41
Sesay, John S; Gyapong, Reginald N K; Najafi, Leila T et al. (2015) G?i/o-dependent Ca(2+) mobilization and G?q-dependent PKC? regulation of Ca(2+)-sensing receptor-mediated responses in N18TG2 neuroblastoma cells. Neurochem Int 90:142-51
Blume, Lawrence C; Eldeeb, Khalil; Bass, Caroline E et al. (2015) Cannabinoid receptor interacting protein (CRIP1a) attenuates CB1R signaling in neuronal cells. Cell Signal 27:716-726

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