A calcium-sensing receptor mutation causing hypocalcemia disrupts a transmembrane salt bridge to activate β-arrestin-biased signaling.
A calcium-sensing receptor mutation causing hypocalcemia disrupts a transmembrane salt bridge to activate β-arrestin-biased signaling.
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DOI：
10.1126/scisignal.aan3714
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发表时间：
2018-02-20
影响因子：
7.3
通讯作者：
Thakker RV
中科院分区：
文献类型：
--
作者：
Gorvin CM;Babinsky VN;Malinauskas T;Nissen PH;Schou AJ;Hanyaloglu AC;Siebold C;Jones EY;Hannan FM;Thakker RV
钙敏感受体（CaSR）是一种G蛋白偶联受体（GPCR），其通过Gq/11和Gi/o信号传导以刺激细胞溶质钙（Ca 2 +i）和丝裂原活化蛋白激酶（MAPK）信号传导来控制细胞外钙稳态。CASR功能丧失和功能获得突变分别导致家族性低钙尿高钙血症1型（FHH 1）和常染色体显性低钙血症1型（ADH 1），研究表明CaSR以偏倚的方式发出信号。因此，与FHH 1相关的一些突变主要通过MAPK途径导致信号传导，而与ADH 1相关的突变优先增强Ca 2 + 1应答。在这里，我们报告了一个以前未识别的ADH 1相关的R680 G CaSR突变，这导致了CaSR结构基序，介导偏置信号的鉴定。在HEK 293细胞中表达R680 G CaSR突变体表明，该突变增加了MAPK信号传导，而不改变Ca 2 +i反应。此外，这种MAPK活性的功能获得独立于Gq/11和GI/o发生，而是由涉及β-抑制蛋白支架蛋白的非经典途径介导。同源建模和诱变研究表明，R680 G CaSR突变通过破坏分别位于CaSR跨膜结构域3和胞外环-2的Arg 680和Glu 767之间形成的盐桥选择性地增强β-arrestin信号传导。因此，我们的研究结果证明了CaSR信号通过β-arrestin和Arg 680-Glu 767盐桥在介导信号偏差中的重要性。
The calcium-sensing receptor (CaSR) is a G protein–coupled receptor (GPCR) that signals through Gq/11 and Gi/o to stimulate cytosolic calcium (Ca2+i) and mitogen-activated protein kinase (MAPK) signaling to control extracellular calcium homeostasis. Studies of loss- and gain-of-function CASR mutations, which cause familial hypocalciuric hypercalcemia type 1 (FHH1) and autosomal dominant hypocalcemia type 1 (ADH1), respectively, have revealed the CaSR to signal in a biased manner. Thus, some mutations associated with FHH1 lead to signaling predominantly through the MAPK pathway, whereas mutations associated with ADH1 preferentially enhance Ca2+i responses. Here, we report a previously unidentified ADH1-associated R680G CaSR mutation, which led to the identification of a CaSR structural motif that mediates biased signaling. Expressing the R680G CaSR mutant in HEK293 cells showed that this mutation increased MAPK signaling without altering Ca2+i responses. Moreover, this gain-of-function in MAPK activity occurred independently of Gq/11 and Gi/o, and was mediated instead by a non-canonical pathway involving β-arrestin scaffolding proteins. Homology modeling and mutagenesis studies showed the R680G CaSR mutation selectively enhanced β-arrestin signaling by disrupting a salt bridge formed between Arg680 and Glu767, which are located in the CaSR transmembrane domain 3 and extracellular loop-2, respectively. Thus, our results demonstrate CaSR signaling through β-arrestin and the importance of the Arg680-Glu767 salt bridge in mediating signaling bias.
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影响因子：
6.2
作者：
Gorvin, Caroline M.;Cranston, Treena;Thakker, Rajesh V.
通讯作者：
Thakker, Rajesh V.
影响因子：
4.8
作者：
Hu, JX;Reyes-Cruz, G;Spiegel, AM
通讯作者：
Spiegel, AM
影响因子：
4.8
作者：
Leach, Katie;Wen, Adriel;Christopoulos, Arthur
通讯作者：
Christopoulos, Arthur
影响因子：
4.8
作者：
Daaka, Y;Luttrell, LM;Lefkowitz, RJ
通讯作者：
Lefkowitz, RJ
影响因子：
3.5
作者：
Hannan FM;Howles SA;Rogers A;Cranston T;Gorvin CM;Babinsky VN;Reed AA;Thakker CE;Bockenhauer D;Brown RS;Connell JM;Cook J;Darzy K;Ehtisham S;Graham U;Hulse T;Hunter SJ;Izatt L;Kumar D;McKenna MJ;McKnight JA;Morrison PJ;Mughal MZ;O'Halloran D;Pearce SH;Porteous ME;Rahman M;Richardson T;Robinson R;Scheers I;Siddique H;Van't Hoff WG;Wang T;Whyte MP;Nesbit MA;Thakker RV
通讯作者：
Thakker RV