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Modulation of Cell Specific Signaling by Cross‐Linking Receptors with Multivalent Ligands
Author(s) -
Weber Craig S,
Vagner Josef,
Josan Jatinder S,
Gillies Robert,
Lynch Ronald M
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.816.10
Subject(s) - receptor , agonist , chemistry , cholecystokinin , intracellular , g protein coupled receptor , hek 293 cells , signal transduction , microbiology and biotechnology , cholecystokinin receptor , biophysics , ligand (biochemistry) , functional selectivity , biochemistry , biology
Connecting two ligands with a flexible linker produces a molecule with potential to cross‐link multiple receptors on a cells surface. We previously showed that a hetero‐multivalent ligand (htMVL) composed of melanocyte stimulating hormone (MSH) and cholecystokinin (CCK) parmacophores connected by peptidomimetic linkers exhibits a >50 fold increase in binding affinity (relative to monomers) only to cells expressing both receptors. Here we evaluate the signaling properties of this htMVL by measuring intracellular Ca 2+ ([Ca 2+ ] i ) in HEK cells engineered to express both receptors. CCK by itself elevates [Ca 2+ ] i , while MSH elevates cAMP at sub‐μM concentrations. The CCK induced Ca 2+ response was abolished when both monovalent ligands were added together, suggesting synergy between the two receptors. Conversely, the MSK/CCK ligand elicited an elevation in [Ca 2+ ] i though it was significantly attenuated compared to monovalent CCK. Since the binding affinity of the htMVL is greater than the CCK monomer, this htMVL acts as a weak agonist by itself, but a super‐antagonist of the normal CCK response. Further, the cell signaling properties of the htMVL is further evidence that this agent is binding to and activating both receptors simultaneously. Our findings indicate that htMVLs may provide new pharmacological tools for altering cell‐type specific signaling. Supported by NIH, RO1 CA097360 and CA123547.