title: Calcium sensing receptor mutations implicated in pancreatitis and idiopathic epilepsy syndrome disrupt an arginine-rich retention motif.
abstract: Calcium sensing receptor (CaSR) mutations implicated in familial hypocalciuric hypercalcemia, pancreatitis and idiopathic epilepsy syndrome map to an extended arginine-rich region in the proximal carboxyl terminus. Arginine-rich motifs mediate endoplasmic reticulum retention and/or retrieval of multisubunit proteins so we asked whether these mutations, R886P, R896H or R898Q, altered CaSR targeting to the plasma membrane. Targeting was enhanced by all three mutations, and Ca(2+)-stimulated ERK1/2 phosphorylation was increased for R896H and R898Q. To define the role of the extended arginine-rich region in CaSR trafficking, we independently determined the contributions of R890/R891 and/or R896/K897/R898 motifs by mutation to alanine. Disruption of the motif(s) significantly increased surface expression and function relative to wt CaSR. The arginine-rich region is flanked by phosphorylation sites at S892 (protein kinase C) and S899 (protein kinase A). The phosphorylation state of S899 regulated recognition of the arginine-rich region; S899D showed increased surface localization. CaSR assembles in the endoplasmic reticulum as a covalent disulfide-linked dimer and we determined whether retention requires the presence of arginine-rich regions in both subunits. A single arginine-rich region within the dimer was sufficient to confer intracellular retention comparable to wt CaSR. We have identified an extended arginine-rich region in the proximal carboxyl terminus of CaSR (residues R890 - R898) which fosters intracellular retention of CaSR and is regulated by phosphorylation. Mutation(s) identified in chronic pancreatitis and idiopathic epilepsy syndrome therefore increase plasma membrane targeting of CaSR, likely contributing to the altered Ca(2+) signaling characteristic of these diseases.
authors.affiliation: Weis Center for Research, Geisinger Clinic, Danville, PA 17822, USA.
authors.forename: Ann
authors.initials: A
authors.lastname: Stepanchick
authors.forename: Jennifer
authors.initials: J
authors.lastname: McKenna
authors.forename: Olivia
authors.initials: O
authors.lastname: McGovern
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Gerda E
authors.initials: GE
authors.lastname: Breitwieser
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D020013:Calcium Signaling; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004827:Epilepsy / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010195:Pancreatitis / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D044169:Receptors, Calcium-Sensing / Q000235:genetics / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D044169:Receptors, Calcium-Sensing
references.citation: Exp Clin Endocrinol Diabetes. 2003 Feb;111(1):21-6
references.pmid: 12605346
references.citation: Trends Pharmacol Sci. 2005 Mar;26(3):131-7
references.pmid: 15749158
references.citation: J Biol Chem. 2001 Nov 23;276(47):44129-36
references.pmid: 11535593
references.citation: J Biol Chem. 2002 Dec 20;277(51):49691-9
references.pmid: 12399473
references.citation: J Biol Chem. 2001 Oct 19;276(42):39053-9
references.pmid: 11489900
references.citation: Biochim Biophys Acta. 2007 Apr;1768(4):853-70
references.pmid: 17074298
references.citation: Annu Rev Med. 2010;61:413-24
references.pmid: 20059346
references.citation: Neuropharmacology. 2003 Nov;45(6):755-67
references.pmid: 14529714
references.citation: Kidney Int. 2007 Jun;71(11):1155-62
references.pmid: 17332735
references.citation: J Biol Chem. 2005 Mar 25;280(12):11140-6
references.pmid: 15657061
references.citation: J Clin Endocrinol Metab. 2000 Apr;85(4):1695-702
references.pmid: 10770217
references.citation: Biol Chem. 2006 Sep;387(9):1227-36
references.pmid: 16972791
references.citation: J Biol Chem. 2007 Mar 30;282(13):9517-9525
references.pmid: 17284438
references.citation: Am J Physiol. 1998 Mar;274(3):F611-22
references.pmid: 9530279
references.citation: Nat Rev Mol Cell Biol. 2004 Dec;5(12):959-70
references.pmid: 15573134
references.citation: J Biol Chem. 1998 Dec 18;273(51):34558-67
references.pmid: 9852126
references.citation: J Endocrinol. 2010 Mar;204(3):287-97
references.pmid: 20032198
references.citation: J Cell Biol. 1999 May 31;145(5):951-9
references.pmid: 10352013
references.citation: J Biol Chem. 2002 Dec 27;277(52):50543-9
references.pmid: 12409307
references.citation: Hum Mutat. 2004 Aug;24(2):107-11
references.pmid: 15241791
references.citation: Brain Res Dev Brain Res. 1997 May 20;100(1):13-21
references.pmid: 9174241
references.citation: Traffic. 2004 Dec;5(12):993-1005
references.pmid: 15522100
references.citation: J Biol Chem. 1997 Dec 12;272(50):31355-61
references.pmid: 9395465
references.citation: Pflugers Arch. 2000 Dec;441(2-3):379-87
references.pmid: 11211126
references.citation: J Biol Chem. 1998 Nov 6;273(45):29712-8
references.pmid: 9792684
references.citation: Subcell Biochem. 2007;45:139-67
references.pmid: 18193637
references.citation: Mol Endocrinol. 2009 Jul;23(7):1115-23
references.pmid: 19389809
references.citation: J Biol Chem. 1999 Jul 16;274(29):20561-8
references.pmid: 10400686
references.citation: Curr Biol. 2003 Apr 15;13(8):638-46
references.pmid: 12699619
references.citation: Annu Rev Genomics Hum Genet. 2009;10:63-87
references.pmid: 19453252
references.citation: J Invest Dermatol. 2007 May;127(5):1074-83
references.pmid: 17124506
references.citation: Physiol Rev. 2007 Jul;87(3):965-1010
references.pmid: 17615394
references.citation: J Clin Endocrinol Metab. 2007 Nov;92(11):4373-9
references.pmid: 17698911
references.citation: J Clin Endocrinol Metab. 2001 Nov;86(11):5313-23
references.pmid: 11701698
references.citation: Scand J Gastroenterol. 2006 Mar;41(3):343-8
references.pmid: 16497624
references.citation: J Biol Chem. 2008 Sep 5;283(36):24435-47
references.pmid: 18621740
references.citation: Curr Pharm Biotechnol. 2009 Apr;10(3):270-81
references.pmid: 19355937
references.citation: Medicine (Baltimore). 2002 Jan;81(1):1-26
references.pmid: 11807402
references.citation: World J Gastroenterol. 2008 Jul 28;14(28):4486-91
references.pmid: 18680227
references.citation: Ann Neurol. 2008 Aug;64(2):158-67
references.pmid: 18756473
references.citation: Nat Neurosci. 2008 Mar;11(3):285-91
references.pmid: 18223649
references.citation: J Neurosci. 2001 Feb 15;21(4):1189-202
references.pmid: 11160389
references.citation: Cell. 2002 Nov 15;111(4):577-88
references.pmid: 12437930