TY - JOUR
T1 - Evidence that specific interactions play a role in the cholesterol sensitivity of G protein-coupled receptors
AU - Geiger, James
AU - Sexton, Rick
AU - Al-Sahouri, Zina
AU - Lee, Ming Yue
AU - Chun, Eugene
AU - Harikumar, Kaleeckal G.
AU - Miller, Laurence J.
AU - Beckstein, Oliver
AU - Liu, Wei
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/9/1
Y1 - 2021/9/1
N2 - G protein-coupled receptors (GPCRs) are known to be modulated by membrane cholesterol levels, but whether or not the effects are caused by specific receptor-cholesterol interactions or cholesterol's general effects on the membrane is not well-understood. We performed coarse-grained molecular dynamics (CGMD) simulations coupled with structural bioinformatics approaches on the β2-adrenergic receptor (β2AR) and the cholecystokinin (CCK) receptor subfamily. The β2AR has been shown to be sensitive to membrane cholesterol and cholesterol molecules have been clearly resolved in numerous β2AR crystal structures. The two CCK receptors are highly homologous and preserve similar cholesterol recognition motifs but despite their homology, CCK1R shows functional sensitivity to membrane cholesterol while CCK2R does not. Our results offer new insights into how cholesterol modulates GPCR function by showing cholesterol interactions with β2AR that agree with previously published data; additionally, we observe differential and specific cholesterol binding in the CCK receptor subfamily while revealing a previously unreported Cholesterol Recognition Amino-acid Consensus (CRAC) sequence that is also conserved across 38% of class A GPCRs. A thermal denaturation assay (LCP-Tm) shows that mutation of a conserved CRAC sequence on TM7 of the β2AR affects cholesterol stabilization of the receptor in a lipid bilayer. The results of this study provide a better understanding of receptor-cholesterol interactions that can contribute to novel and improved therapeutics for a variety of diseases.
AB - G protein-coupled receptors (GPCRs) are known to be modulated by membrane cholesterol levels, but whether or not the effects are caused by specific receptor-cholesterol interactions or cholesterol's general effects on the membrane is not well-understood. We performed coarse-grained molecular dynamics (CGMD) simulations coupled with structural bioinformatics approaches on the β2-adrenergic receptor (β2AR) and the cholecystokinin (CCK) receptor subfamily. The β2AR has been shown to be sensitive to membrane cholesterol and cholesterol molecules have been clearly resolved in numerous β2AR crystal structures. The two CCK receptors are highly homologous and preserve similar cholesterol recognition motifs but despite their homology, CCK1R shows functional sensitivity to membrane cholesterol while CCK2R does not. Our results offer new insights into how cholesterol modulates GPCR function by showing cholesterol interactions with β2AR that agree with previously published data; additionally, we observe differential and specific cholesterol binding in the CCK receptor subfamily while revealing a previously unreported Cholesterol Recognition Amino-acid Consensus (CRAC) sequence that is also conserved across 38% of class A GPCRs. A thermal denaturation assay (LCP-Tm) shows that mutation of a conserved CRAC sequence on TM7 of the β2AR affects cholesterol stabilization of the receptor in a lipid bilayer. The results of this study provide a better understanding of receptor-cholesterol interactions that can contribute to novel and improved therapeutics for a variety of diseases.
KW - Cholecystokinin (CCK) receptors
KW - Cholesterol
KW - Cholesterol recognition amino-acid consensus (CRAC)
KW - Course-grained molecular dynamics
KW - G protein-coupled receptors
UR - http://www.scopus.com/inward/record.url?scp=85099613775&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85099613775&partnerID=8YFLogxK
U2 - 10.1016/j.bbamem.2021.183557
DO - 10.1016/j.bbamem.2021.183557
M3 - Article
C2 - 33444621
AN - SCOPUS:85099613775
SN - 0005-2736
VL - 1863
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 9
M1 - 183557
ER -