Project 7 - Cell-specific CaSR signaling

Host Institution: University of Manchester
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Hypothesis: CaSR signalling involves pleiotropic interactions between multiple G protein pathways with the potential for cell-specific competition between these effectors known as conditional efficacy.

Objectives:To determine the relative stoichiometry of CaSR partner/effector proteins between different cell-types and then relate these to their differential responsiveness. ESR_UM will use HEK-293, endothelial (HUVEC), parathyroid (PTH-C1), and colonic cells to compare CaSR signalling responses among cell types [Ca²⁺i and a panel of kinase effectors]. Phosphorylation of the CaSR on T888 is a crucial signalling control. Therefore, ESR_UM will compare the relative activities of gain-of-function (T888A) and loss-of-function (T888D) CaSR mutants between the 4 cell types in order to identify cell-specific differences in the consequence of CaSRT888 phosphorylation. Finally, ESRUM will examine the relative effects of altering intracellular cAMP concentration or relative expression of particular effector proteins (G_q/11, G_i/o, G_12/13, rho & rho-GEF) in the different cells to show how these alter CaSR signalling dynamics.