Allosteric Modulation of the Calcium-sensing Receptor Rectifies Signaling Abnormalities Associated with G-protein alpha-11 Mutations Causing Hypercalcemic and Hypocalcemic Disorders

作者：Babinsky Valerie N; Hannan Fadil M; Gorvin Caroline M; Howles Sarah A; Ne**it M Andrew; Rust Nigel; Hanyaloglu Aylin C; Hu Jianxin; Spiegel Allen M; Thakker Rajesh V^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2016, 291(20): 10876-10885.

DOI：10.1074/jbc.M115.696401

Germline loss- and gain-of-function mutations of G-protein alpha-11 (G alpha(11)), which couples the calcium-sensing receptor (CaSR) to intracellular calcium (Ca-i(2+)) signaling, lead to familial hypocalciuric hypercalcemia type 2 (FHH2) and autosomal dominant hypocalcemia type 2 (ADH2), respectively, whereas somatic Gall mutations mediate uveal melanoma development by constitutively up-regulating MAPK signaling. Cinacalcet and NPS-2143 are allosteric CaSR activators and inactivators, respectively, that ameliorate signaling disturbances associated with CaSR mutations, but their potential to modulate abnormalities of the downstream Gall protein is unknown. This study investigated whether cinacalcet and NPS-2143 may rectify Ca-i(2+) alterations associated with FHH2- and ADH2-causing Got, mutations, and evaluated the influence of germline gain of-function Gall mutations on MAPK signaling by measuring ERK phosphorylation, and assessed the effect of NPS-2143 on a uveal melanoma Gall mutant. WT and mutant G alpha(11) proteins causing FHH2, ADH2 or uveal melanoma were transfected in CaSR-expressing HEK293 cells, and Ca-i(2+) and ERK phosphorylation responses measured by flow-cytometry and Alphascreen immunoassay following exposure to extracellular Ca2+ (Ca-0(2+)) and allosteric modulators. Cinacalcet and NPS-2143 rectified the Ca-i(2+) responses of FHH2- and ADH2-associated G alpha(11) loss and gain-of-function mutations, respectively. ADH2-causing

• 出版日期2016-5-13
• 单位NIH