title: Ca2+/calmodulin regulates trafficking of Ca(V)1.2 Ca2+ channels in cultured hippocampal neurons.
abstract: As the Ca2+-sensor for Ca2+-dependent inactivation, calmodulin (CaM) has been proposed, but never definitively demonstrated, to be a constitutive Ca(V)1.2 Ca2+ channel subunit. Here we show that CaM is associated with the Ca(V)1.2 pore-forming alpha1C subunit in brain in a Ca2+-independent manner. Within its CaM binding pocket, alpha1C has been proposed to contain a membrane targeting domain. Because ion channel subunits assemble early during channel biosynthesis, we postulated that this association with CaM could afford the opportunity for Ca2+-dependent regulation of membrane targeting. We showed that the isolated domain functioned as a Ca2+/CaM regulated trafficking determinant for CD8 (a model transmembrane protein) using fluorescent-activated cell sorting analysis and, using green fluorescent protein-tagged alpha1C subunits expressed in cultured hippocampal neurons, that Ca2+/CaM interaction with this domain accelerated trafficking of Ca(V)1.2 channels to distal regions of the dendritic arbor. Furthermore, this Ca2+/CaM-accelerated trafficking was activity dependent. Thus, CaM imparts Ca2+-dependent regulation not only to mature Ca(V)1.2 channels at the cell surface but also to steps during channel biosynthesis.
authors: Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
authors: Hong-Gang
authors: HG
authors: Wang
authors: Meena S
authors: MS
authors: George
authors: James
authors: J
authors: Kim
authors: Chaojian
authors: C
authors: Wang
authors: Geoffrey S
authors: GS
authors: Pitt
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism*; D002147:Calmodulin / Q000502:physiology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology*; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D008954:Models, Biological; D009154:Mutation / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection
chemical_list: D020746:Calcium Channels, L-Type; D002147:Calmodulin; C419385:L-type calcium channel alpha(1C); D049452:Green Fluorescent Proteins; D002118:Calcium
references: Neuron. 1999 Mar;22(3):549-58
references: 10197534
references: Nature. 1999 May 13;399(6732):155-9
references: 10335845
references: Nature. 1999 May 13;399(6732):159-62
references: 10335846
references: Neuron. 2000 Mar;25(3):533-5
references: 10774722
references: J Biol Chem. 2000 Aug 18;275(33):25436-44
references: 10816591
references: Nature. 2001 May 24;411(6836):484-9
references: 11373682
references: J Biol Chem. 2001 Aug 3;276(31):28920-6
references: 11384990
references: J Biol Chem. 2001 Aug 17;276(33):30794-802
references: 11408490
references: Science. 2001 Jul 6;293(5527):98-101
references: 11441182
references: J Biol Chem. 2001 Oct 12;276(41):37980-5
references: 11495911
references: Science. 2001 Oct 12;294(5541):333-9
references: 11598293
references: Nat Neurosci. 2002 Mar;5(3):210-7
references: 11865310
references: Nat Rev Neurosci. 2002 Nov;3(11):873-83
references: 12415295
references: Nat Rev Neurosci. 2002 Dec;3(12):921-31
references: 12461549
references: J Neurosci. 2003 Apr 15;23(8):3446-56
references: 12716953
references: J Biol Chem. 2003 Jul 11;278(28):25940-6
references: 12734181
references: Curr Opin Neurobiol. 2003 Jun;13(3):354-65
references: 12850221
references: Nat Neurosci. 2003 Sep;6(9):948-55
references: 12937422
references: Neuron. 2003 Sep 11;39(6):951-60
references: 12971895
references: Neuron. 2003 Oct 9;40(2):265-76
references: 14556708
references: J Bioenerg Biomembr. 2003 Dec;35(6):599-620
references: 15000522
references: Neuron. 2004 Mar 4;41(5):745-54
references: 15003174
references: Science. 2004 Apr 16;304(5669):432-5
references: 15087548
references: Eur J Neurosci. 2004 Apr;19(8):2109-22
references: 15090038
references: J Neurosci. 2004 May 12;24(19):4698-708
references: 15140941
references: J Neurosci. 2005 Jul 27;25(30):7062-70
references: 16049183
references: EMBO Rep. 2005 Aug;6(8):717-22
references: 16065065
references: J Neurosci. 2005 Oct 26;25(43):9883-92
references: 16251435
references: Circ Res. 2006 Apr 28;98(8):1055-63
references: 16556865
references: Circ Res. 2006 Apr 28;98(8):1048-54
references: 16556866
references: Eur J Neurosci. 2006 May;23(9):2297-310
references: 16706838
references: J Neurosci. 2006 Oct 18;26(42):10677-89
references: 17050707
references: Biochem Soc Trans. 2006 Nov;34(Pt 5):903-9
references: 17052224
references: Neuron. 1996 Jan;16(1):89-101
references: 8562094
references: Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1903-8
references: 9465115
references: Nature. 1998 Mar 12;392(6672):198-202
references: 9515967
references: J Neurosci. 1998 Aug 15;18(16):6319-30
references: 9698323