Date of Award
Robert M. Dores, Ph.D.
Cynthia V. Fukami
ACTH, Adrenocorticotropic hormone, Activation, CHO-K1, MC2R, Melanocortin 2 receptor, Melanocortin, Silurana Tropicalis
Melanocortin receptor ligand selectivity has been a question not easily answered. The inability to functionally express melanocortin 2 receptor (MC2R) has inhibited the study of why MC2R is only stimulated by ACTH, a melanocortin hormone. With the recent discovery of the MC2R accessory protein (MRAP), creating a heterologous system is now feasible. Using a general cell line like CHO-K1 cells, which do not express endogenous MCRs, we were able to create a heterologous expression system and test the selectivity of MC2R using analog variants of ACTH(1-24). Our results indicate an amino acid requirement in the C-terminal portion of ACTH(1-24) for activation, which supports the 2-step method of activation hypothesized for MC2R. This site, the tetra basic cleavage site, when altered does not stimulate cAMP production and does not compete with ACTH(1-24) for binding. We also demonstrate the potential for a non-mammalian MC2R system in cloning full length Silurana tropicalis MC2R and completed localization studies with this system with MRAP using CHO-K1 cells.
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Kristopher D. Veo
Received from ProQuest
Veo, Kristopher D., "Amino Acid Residues Implicated in the Interaction of Melanocortin Ligands and Their Receptors: A Study of MC2R Selectivity" (2009). Electronic Theses and Dissertations. 945.