Our goal is to better understand the role of cholecystokinin (CCK) in health and disease. This gut and brain hormone exists in multiple molecular forms, ranging in size from 4 to 58 amino acids, with functions including regulation of pancreatic secretion, gallbladder contraction, gastrointestinal motility, trophic effects, and satiety. Our approach is 3 fold: a) characterization and quantification of CCK peptides, b) functional and biochemical characterization of CCK receptors, and c) description of the molecular events associated with CCK-receptor interaction, including receptor activation and initiation of the effector cascade. The peptide-related components include: 1) the chemical and mass spectrometric elucidation of the primary structure of large human CCK peptides, 2) the establishment and validation of complementary approaches to the quantification of human CCK peptides (RIA, radioreceptor assay, and bioassay), and 3) the experimental (fluorescence, UV, and CD spectroscopy and NMR) and theoretical approaches to the determination of the conformation of the receptor-binding region of CCK. The receptor-related components include a major commitment to the development of new methodology, with initial application to the pancreatic acinar cell receptor; subsequent application will be to gastrointestinal smooth muscle, studying preparations of fresh and cultured, healthy and neoplastic cells and their membranes. We plan to develop a series of new probes for the CCK-binding region of the receptor; these will include 1) short CCK analogues with free amino groups available for chemical crosslinking, 2) analogues with incorporated aryl nitrene and carbene precursors for photoaffinity labeling, 3) anti-idiotypic antibodies, and 4) naturally-occurring auto-antibodies. We also plan to generate a series of immunologic probes for this receptor and its associated molecules, and to solubilize, purify, and reconstitute these in a functional state. These studies should further our understanding of the mechanisms whereby this hormone interacts with its receptor to activate it and initiate the effector cascade within target cells. This may help in the understanding of potential aberrations of CCK-receptor interaction which may occur in disease stages, and may have more general basic cellular and molecular implications for the important process of message transduction across a membrane.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK032878-04
Application #
3231229
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1983-08-01
Project End
1991-07-31
Budget Start
1986-08-01
Budget End
1987-07-31
Support Year
4
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
City
Rochester
State
MN
Country
United States
Zip Code
55905
Desai, A J; Dong, M; Harikumar, K G et al. (2016) Cholecystokinin-induced satiety, a key gut servomechanism that is affected by the membrane microenvironment of this receptor. Int J Obes Suppl 6:S22-S27
Miller, Laurence J; Desai, Aditya J (2016) Metabolic Actions of the Type 1 Cholecystokinin Receptor: Its Potential as a Therapeutic Target. Trends Endocrinol Metab 27:609-619
Desai, Aditya J; Dong, Maoqing; Miller, Laurence J (2016) Beneficial effects of ?-sitosterol on type 1 cholecystokinin receptor dysfunction induced by elevated membrane cholesterol. Clin Nutr 35:1374-1379
Desai, Aditya J; Henke, Brad R; Miller, Laurence J (2015) Elimination of a cholecystokinin receptor agonist 'trigger' in an effort to develop positive allosteric modulators without intrinsic agonist activity. Bioorg Med Chem Lett 25:1849-55
Harikumar, Kaleeckal G; Miller, Laurence J (2015) Use of Fluorescence Indicators in Receptor Ligands. Methods Mol Biol 1335:115-30
Desai, Aditya J; Lam, Polo C H; Orry, Andrew et al. (2015) Molecular Mechanism of Action of Triazolobenzodiazepinone Agonists of the Type 1 Cholecystokinin Receptor. Possible Cooperativity across the Receptor Homodimeric Complex. J Med Chem 58:9562-77
Desai, Aditya J; Dong, Maoqing; Harikumar, Kaleeckal G et al. (2015) Impact of ursodeoxycholic acid on a CCK1R cholesterol-binding site may contribute to its positive effects in digestive function. Am J Physiol Gastrointest Liver Physiol 309:G377-86
Dong, Maoqing; Vattelana, Ashton M; Lam, Polo C-H et al. (2015) Development of a highly selective allosteric antagonist radioligand for the type 1 cholecystokinin receptor and elucidation of its molecular basis of binding. Mol Pharmacol 87:130-40
Desai, Aditya J; Harikumar, Kaleeckal G; Miller, Laurence J (2014) A type 1 cholecystokinin receptor mutant that mimics the dysfunction observed for wild type receptor in a high cholesterol environment. J Biol Chem 289:18314-26
Dong, Maoqing; Miller, Laurence J (2013) Direct demonstration of unique mode of natural peptide binding to the type 2 cholecystokinin receptor using photoaffinity labeling. Peptides 46:143-9

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