Identification of Serine-875 as an Inhibitory Phosphorylation Site in the Calcium-Sensing Receptor.Citation formats

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Identification of Serine-875 as an Inhibitory Phosphorylation Site in the Calcium-Sensing Receptor. / Ward, Donald.

In: Molecular pharmacology, 2019.

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@article{4d647548f2ee459eb8d94e3157b407fc,
title = "Identification of Serine-875 as an Inhibitory Phosphorylation Site in the Calcium-Sensing Receptor.",
abstract = "The calcium-sensing receptor (CaS) is the principal controller of extracellular calcium (Ca2+o) homeostasis and is inhibited in vitro and in vivo by protein kinase C (PKC)-mediated phosphorylation at CaST888. However, PKC inhibition enhances signalling even in CaSs lacking Thr-888, suggesting that an additional inhibitory site exists. An apparently equivalent PKC regulatory site in metabotropic glutamate receptor-5 (Ser-839) aligns not with CaST888 but instead with CaSS875, not previously considered a PKC site. CaSS875A (non-phosphorylatable) exhibited significantly enhanced Ca2+o sensitivity of both intracellular Ca2+ mobilisation and extracellular signal-regulated kinase 1/2 (ERK1/2) activation, whereas the phosphomimetic CaSS875D mutant exhibited a loss of function. The CaSS875A/T888A double mutant exhibited even greater Ca2+o sensitivity than CaST888A alone, a response no longer enhanced by PKC inhibition. Finally, when expressed in CaS lacking its extracellular domain, the CaSS875A/T888A double mutation elicited maximal activation even under control conditions, but remained sensitive to negative allosteric modulation (NPS-2143) or Ca2+o removal. Therefore, we have now identified CaSS875 as the missing PKC phosphorylation site that, together with CaST888, shapes the CaS signalling that underpins Ca2+o homeostasis. Together with the inactive form of the CaS{\textquoteright}s extracellular domain, these sites attenuate Ca2+o sensitivity to attain appropriate physiological Ca2+o sensing. ",
author = "Donald Ward",
year = "2019",
doi = "10.1124/mol.119.116178",
language = "English",
journal = "Molecular pharmacology",
issn = "0026-8950",
publisher = "American Society for Pharmacology and Experimental Therapeutics",

}

RIS

TY - JOUR

T1 - Identification of Serine-875 as an Inhibitory Phosphorylation Site in the Calcium-Sensing Receptor.

AU - Ward, Donald

PY - 2019

Y1 - 2019

N2 - The calcium-sensing receptor (CaS) is the principal controller of extracellular calcium (Ca2+o) homeostasis and is inhibited in vitro and in vivo by protein kinase C (PKC)-mediated phosphorylation at CaST888. However, PKC inhibition enhances signalling even in CaSs lacking Thr-888, suggesting that an additional inhibitory site exists. An apparently equivalent PKC regulatory site in metabotropic glutamate receptor-5 (Ser-839) aligns not with CaST888 but instead with CaSS875, not previously considered a PKC site. CaSS875A (non-phosphorylatable) exhibited significantly enhanced Ca2+o sensitivity of both intracellular Ca2+ mobilisation and extracellular signal-regulated kinase 1/2 (ERK1/2) activation, whereas the phosphomimetic CaSS875D mutant exhibited a loss of function. The CaSS875A/T888A double mutant exhibited even greater Ca2+o sensitivity than CaST888A alone, a response no longer enhanced by PKC inhibition. Finally, when expressed in CaS lacking its extracellular domain, the CaSS875A/T888A double mutation elicited maximal activation even under control conditions, but remained sensitive to negative allosteric modulation (NPS-2143) or Ca2+o removal. Therefore, we have now identified CaSS875 as the missing PKC phosphorylation site that, together with CaST888, shapes the CaS signalling that underpins Ca2+o homeostasis. Together with the inactive form of the CaS’s extracellular domain, these sites attenuate Ca2+o sensitivity to attain appropriate physiological Ca2+o sensing.

AB - The calcium-sensing receptor (CaS) is the principal controller of extracellular calcium (Ca2+o) homeostasis and is inhibited in vitro and in vivo by protein kinase C (PKC)-mediated phosphorylation at CaST888. However, PKC inhibition enhances signalling even in CaSs lacking Thr-888, suggesting that an additional inhibitory site exists. An apparently equivalent PKC regulatory site in metabotropic glutamate receptor-5 (Ser-839) aligns not with CaST888 but instead with CaSS875, not previously considered a PKC site. CaSS875A (non-phosphorylatable) exhibited significantly enhanced Ca2+o sensitivity of both intracellular Ca2+ mobilisation and extracellular signal-regulated kinase 1/2 (ERK1/2) activation, whereas the phosphomimetic CaSS875D mutant exhibited a loss of function. The CaSS875A/T888A double mutant exhibited even greater Ca2+o sensitivity than CaST888A alone, a response no longer enhanced by PKC inhibition. Finally, when expressed in CaS lacking its extracellular domain, the CaSS875A/T888A double mutation elicited maximal activation even under control conditions, but remained sensitive to negative allosteric modulation (NPS-2143) or Ca2+o removal. Therefore, we have now identified CaSS875 as the missing PKC phosphorylation site that, together with CaST888, shapes the CaS signalling that underpins Ca2+o homeostasis. Together with the inactive form of the CaS’s extracellular domain, these sites attenuate Ca2+o sensitivity to attain appropriate physiological Ca2+o sensing.

U2 - 10.1124/mol.119.116178

DO - 10.1124/mol.119.116178

M3 - Article

JO - Molecular pharmacology

JF - Molecular pharmacology

SN - 0026-8950

ER -