title: Roles of intraloops-2 and -3 and the proximal C-terminus in signalling pathway selection from the human calcium-sensing receptor.
abstract: The calcium-sensing receptor (CaSR) couples to signalling pathways via intracellular loops 2 and 3, and the C-terminus. However, the requirements for signalling are largely undefined. We investigated the impacts of selected point mutations in iL-2 (F706A) and iL-3 (L797A and E803A), and a truncation of the C-terminus (R866X) on extracellular Ca(2+) (Ca(2+)o)-stimulated phosphatidylinositol-specific phospholipase-C (PI-PLC) and various other signalling responses. CaSR-mediated activation of PI-PLC was markedly attenuated in all four mutants and similar suppressions were observed for Ca(2+)o-stimulated ERK1/2 phosphorylation. Ca(2+)o-stimulated intracellular Ca(2+) (Ca(2+)i) mobilization, however, was relatively preserved for the iL-2 and iL-3 mutants and suppression of adenylyl cyclase was unaffected by either E803A or R866X. The CaSR selects for specific signalling pathways via the proximal C-terminus and key residues in iL-2, iL-3.
authors: School of Molecular Bioscience, University of Sydney, NSW 2006, Australia.
authors: Mahvash A
authors: MA
authors: Goolam
authors: School of Molecular Bioscience, University of Sydney, NSW 2006, Australia.
authors: James H
authors: JH
authors: Ward
authors: School of Molecular Bioscience, University of Sydney, NSW 2006, Australia.
authors: Vimesh A
authors: VA
authors: Avlani
authors: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia.
authors: Katie
authors: K
authors: Leach
authors: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia.
authors: Arthur
authors: A
authors: Christopoulos
authors: School of Molecular Bioscience, University of Sydney, NSW 2006, Australia. Electronic address: arthur.conigrave@sydney.edu.au.
authors: Arthur D
authors: AD
authors: Conigrave
mesh_terms: D020816:Amino Acid Motifs; D020013:Calcium Signaling; D000242:Cyclic AMP / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D009154:Mutation; D011499:Protein Processing, Post-Translational; D044169:Receptors, Calcium-Sensing / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: C095550:CASR protein, human; D044169:Receptors, Calcium-Sensing; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases; D010738:Type C Phospholipases
keywords: Adenosine 3′,5′-cyclic monophosphate; Biased signalling; Calcium-sensing receptor; ERK(1/2); G-protein coupled receptor; Phosphatidylinositol-specific phospholipase-C