Ca2+/calmodulin regulates trafficking of Ca(V)1.2 Ca2+ channels in cultured hippocampal neurons.
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.
Wang
Hong-Gang
HG
Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
George
Meena S
MS
Kim
James
J
Wang
Chaojian
C
Pitt
Geoffrey S
GS
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
D020746:Calcium Channels, L-Type; D002147:Calmodulin; C419385:L-type calcium channel alpha(1C); D049452:Green Fluorescent Proteins; D002118:Calcium
Neuron. 1999 Mar;22(3):549-58
10197534
Nature. 1999 May 13;399(6732):155-9
10335845
Nature. 1999 May 13;399(6732):159-62
10335846
Neuron. 2000 Mar;25(3):533-5
10774722
J Biol Chem. 2000 Aug 18;275(33):25436-44
10816591
Nature. 2001 May 24;411(6836):484-9
11373682
J Biol Chem. 2001 Aug 3;276(31):28920-6
11384990
J Biol Chem. 2001 Aug 17;276(33):30794-802
11408490
Science. 2001 Jul 6;293(5527):98-101
11441182
J Biol Chem. 2001 Oct 12;276(41):37980-5
11495911
Science. 2001 Oct 12;294(5541):333-9
11598293
Nat Neurosci. 2002 Mar;5(3):210-7
11865310
Nat Rev Neurosci. 2002 Nov;3(11):873-83
12415295
Nat Rev Neurosci. 2002 Dec;3(12):921-31
12461549
J Neurosci. 2003 Apr 15;23(8):3446-56
12716953
J Biol Chem. 2003 Jul 11;278(28):25940-6
12734181
Curr Opin Neurobiol. 2003 Jun;13(3):354-65
12850221
Nat Neurosci. 2003 Sep;6(9):948-55
12937422
Neuron. 2003 Sep 11;39(6):951-60
12971895
Neuron. 2003 Oct 9;40(2):265-76
14556708
J Bioenerg Biomembr. 2003 Dec;35(6):599-620
15000522
Neuron. 2004 Mar 4;41(5):745-54
15003174
Science. 2004 Apr 16;304(5669):432-5
15087548
Eur J Neurosci. 2004 Apr;19(8):2109-22
15090038
J Neurosci. 2004 May 12;24(19):4698-708
15140941
J Neurosci. 2005 Jul 27;25(30):7062-70
16049183
EMBO Rep. 2005 Aug;6(8):717-22
16065065
J Neurosci. 2005 Oct 26;25(43):9883-92
16251435
Circ Res. 2006 Apr 28;98(8):1055-63
16556865
Circ Res. 2006 Apr 28;98(8):1048-54
16556866
Eur J Neurosci. 2006 May;23(9):2297-310
16706838
J Neurosci. 2006 Oct 18;26(42):10677-89
17050707
Biochem Soc Trans. 2006 Nov;34(Pt 5):903-9
17052224
Neuron. 1996 Jan;16(1):89-101
8562094
Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1903-8
9465115
Nature. 1998 Mar 12;392(6672):198-202
9515967
J Neurosci. 1998 Aug 15;18(16):6319-30
9698323