Allosteric and orthosteric sites in CC chemokine receptor (CCR5), a chimeric receptor approach

TY - JOUR

T1 - Allosteric and orthosteric sites in CC chemokine receptor (CCR5), a chimeric receptor approach

AU - Thiele, Stefanie

AU - Steen, Anne

AU - Jensen, Pia C

AU - Mokrosinski, Jacek

AU - Frimurer, Thomas M

AU - Rosenkilde, Mette M

PY - 2011/10/28

Y1 - 2011/10/28

N2 - Chemokine receptors play a major role in immune system regulation and have consequently been targets for drug development leading to the discovery of several small molecule antagonists. Given the large size and predominantly extracellular receptor interaction of endogenous chemokines, small molecules often act more deeply in an allosteric mode. However, opposed to the well described molecular interaction of allosteric modulators in class C 7-transmembrane helix (7TM) receptors, the interaction in class A, to which the chemokine receptors belong, is more sparsely described. Using the CCR5 chemokine receptor as a model system, we studied the molecular interaction and conformational interchange required for proper action of various orthosteric chemokines and allosteric small molecules, including the well known CCR5 antagonists TAK-779, SCH-C, and aplaviroc, and four novel CCR5 ago-allosteric molecules. A chimera was successfully constructed between CCR5 and the closely related CCR2 by transferring all extracellular regions of CCR2 to CCR5, i.e. a Trojan horse that resembles CCR2 extracellularly but signals through a CCR5 transmembrane unit. The chimera bound CCR2 (CCL2 and CCL7), but not CCR5 chemokines (CCL3 and CCL5), with CCR2-like high affinities and potencies throughout the CCR5 signaling unit. Concomitantly, high affinity binding of small molecule CCR5 agonists and antagonists was retained in the transmembrane region. Importantly, whereas the agonistic and antagonistic properties were preserved, the allosteric enhancement of chemokine binding was disrupted. In summary, the Trojan horse chimera revealed that orthosteric and allosteric sites could be structurally separated and still act together with transmission of agonism and antagonism across the different receptor units.

AB - Chemokine receptors play a major role in immune system regulation and have consequently been targets for drug development leading to the discovery of several small molecule antagonists. Given the large size and predominantly extracellular receptor interaction of endogenous chemokines, small molecules often act more deeply in an allosteric mode. However, opposed to the well described molecular interaction of allosteric modulators in class C 7-transmembrane helix (7TM) receptors, the interaction in class A, to which the chemokine receptors belong, is more sparsely described. Using the CCR5 chemokine receptor as a model system, we studied the molecular interaction and conformational interchange required for proper action of various orthosteric chemokines and allosteric small molecules, including the well known CCR5 antagonists TAK-779, SCH-C, and aplaviroc, and four novel CCR5 ago-allosteric molecules. A chimera was successfully constructed between CCR5 and the closely related CCR2 by transferring all extracellular regions of CCR2 to CCR5, i.e. a Trojan horse that resembles CCR2 extracellularly but signals through a CCR5 transmembrane unit. The chimera bound CCR2 (CCL2 and CCL7), but not CCR5 chemokines (CCL3 and CCL5), with CCR2-like high affinities and potencies throughout the CCR5 signaling unit. Concomitantly, high affinity binding of small molecule CCR5 agonists and antagonists was retained in the transmembrane region. Importantly, whereas the agonistic and antagonistic properties were preserved, the allosteric enhancement of chemokine binding was disrupted. In summary, the Trojan horse chimera revealed that orthosteric and allosteric sites could be structurally separated and still act together with transmission of agonism and antagonism across the different receptor units.

KW - Allosteric Regulation

KW - Amides

KW - Animals

KW - Benzoates

KW - COS Cells

KW - Cercopithecus aethiops

KW - Chemokines

KW - Cyclic N-Oxides

KW - Humans

KW - Piperazines

KW - Piperidines

KW - Pyridines

KW - Quaternary Ammonium Compounds

KW - Receptors, CCR2

KW - Receptors, CCR5

KW - Recombinant Fusion Proteins

KW - Spiro Compounds

U2 - 10.1074/jbc.M111.243808

DO - 10.1074/jbc.M111.243808

M3 - Journal article

C2 - 21878623

SN - 0021-9258

VL - 286

SP - 37543

EP - 37554

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 43

ER -