TY - JOUR
T1 - Reversible, allosteric small-molecule inhibitors of regulator of G protein signaling proteins
AU - Blazer, L L
AU - Roman, D L
AU - Chung, A
AU - Larsen, M J
AU - Greedy, Ben M
AU - Husbands, Stephen M
AU - Neubig, R R
PY - 2010/9
Y1 - 2010/9
N2 - Regulators of G protein signaling (RGS) proteins are potent negative modulators of G protein signaling and have been proposed as potential targets for small-molecule inhibitor development. We report a high-throughput time-resolved fluorescence resonance energy transfer screen to identify inhibitors of RGS4 and describe the first reversible small-molecule inhibitors of an RGS protein. Two closely related compounds, typified by CCG-63802 [((2E)-2-(1,3-benzothiazol-2-yl)-3-[9-methyl-2-(3-methylphenoxy)-4-oxo-4 H-pyrido[1,2-a]pyrimidin-3-yl]prop-2-enenitrile)], inhibit the interaction between RGS4 and G alpha(o) with an IC50 value in the low micromolar range. They show selectivity among RGS proteins with a potency order of RGS 4 > 19 = 16 > 8 >> 7. The compounds inhibit the GTPase accelerating protein activity of RGS4, and thermal stability studies demonstrate binding to the RGS but not to G alpha(o). On RGS4, they depend on an interaction with one or more cysteines in a pocket that has previously been identified as an allosteric site for RGS regulation by acidic phospholipids. Unlike previous small-molecule RGS inhibitors identified to date, these compounds retain substantial activity under reducing conditions and are fully reversible on the 10-min time scale. CCG-63802 and related analogs represent a useful step toward the development of chemical tools for the study of RGS physiology.
AB - Regulators of G protein signaling (RGS) proteins are potent negative modulators of G protein signaling and have been proposed as potential targets for small-molecule inhibitor development. We report a high-throughput time-resolved fluorescence resonance energy transfer screen to identify inhibitors of RGS4 and describe the first reversible small-molecule inhibitors of an RGS protein. Two closely related compounds, typified by CCG-63802 [((2E)-2-(1,3-benzothiazol-2-yl)-3-[9-methyl-2-(3-methylphenoxy)-4-oxo-4 H-pyrido[1,2-a]pyrimidin-3-yl]prop-2-enenitrile)], inhibit the interaction between RGS4 and G alpha(o) with an IC50 value in the low micromolar range. They show selectivity among RGS proteins with a potency order of RGS 4 > 19 = 16 > 8 >> 7. The compounds inhibit the GTPase accelerating protein activity of RGS4, and thermal stability studies demonstrate binding to the RGS but not to G alpha(o). On RGS4, they depend on an interaction with one or more cysteines in a pocket that has previously been identified as an allosteric site for RGS regulation by acidic phospholipids. Unlike previous small-molecule RGS inhibitors identified to date, these compounds retain substantial activity under reducing conditions and are fully reversible on the 10-min time scale. CCG-63802 and related analogs represent a useful step toward the development of chemical tools for the study of RGS physiology.
UR - http://www.scopus.com/inward/record.url?scp=77956254304&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1124/mol.110.065128
U2 - 10.1124/mol.110.065128
DO - 10.1124/mol.110.065128
M3 - Article
SN - 0026-895X
VL - 78
SP - 524
EP - 533
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 3
ER -