Palmitoylation stabilizes unliganded rod opsin.
S-palmitoylation is a conserved feature in many G protein-coupled receptors (GPCRs) involved in a broad array of signaling processes. The prototypical GPCR, rhodopsin, is S-palmitoylated on two adjacent C-terminal Cys residues at its cytoplasmic surface. Surprisingly, absence of palmitoylation has only a modest effect on in vitro or in vivo signaling. Here, we report that palmitoylation-deficient (Palm(-/-)) mice carrying two Cys to Thr and Ser mutations in the opsin gene displayed profound light-induced retinal degeneration that first involved rod and then cone cells. After brief bright light exposure, their retinas exhibited two types of deposits containing nucleic acid and invasive phagocytic macrophages. When Palm(-/-) mice were crossed with Lrat(-/-) mice lacking lecithin:retinol acyl transferase to eliminate retinoid binding to opsin and thereby rendering the eye insensitive to light, rapid retinal degeneration occurred even in 3- to 4-week-old animals. This rapid degeneration suggests that nonpalmitoylated rod opsin is unstable. Treatment of 2-week-old Palm(-/-)Lrat(-/-) mice with an artificial chromophore precursor prevented this retinopathy. In contrast, elimination of signaling to G protein in Palm(-/-)Gnat1(-/-) mice had no effect, indicating that instability of unpalmitoylated opsin lacking chromophore rather than aberrant signal transduction resulted in retinal pathology. Together, these observations provide evidence for a structural role of rhodopsin S-palmitoylation that may apply to other GPCRs as well.
Maeda
Akiko
A
Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
Okano
Kiichiro
K
Park
Paul S-H
PS
Lem
Janis
J
Crouch
Rosalie K
RK
Maeda
Tadao
T
Palczewski
Krzysztof
K
D000818:Animals; D054878:Lipoylation; D008264:Macrophages / Q000378:metabolism; D008565:Membrane Proteins / Q000172:deficiency / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010750:Phosphoproteins / Q000172:deficiency / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D017299:Rod Opsins / Q000378:metabolism*
D008565:Membrane Proteins; C512641:Palm protein, mouse; D010750:Phosphoproteins; D017299:Rod Opsins
J Biol Chem. 1991 Oct 25;266(30):20118-23
1939072
J Biol Chem. 2004 Mar 12;279(11):10422-32
14684738
Vision Res. 2003 Dec;43(28):2983-90
14611934
J Biol Chem. 2005 Jul 1;280(26):24293-300
15851469
Proc Natl Acad Sci U S A. 1993 Jan 1;90(1):40-4
8419942
Hum Mol Genet. 2009 Jun 15;18(12):2277-87
19339306
Biochemistry. 2003 Mar 18;42(10):2759-67
12627940
Mol Pharmacol. 2009 Jan;75(1):1-12
18945819
Biochemistry. 2009 May 26;48(20):4294-304
19348429
J Biol Chem. 2003 Jul 4;278(27):24896-24903
12707280
J Biol Chem. 2009 May 29;284(22):15173-83
19304658
Proc Natl Acad Sci U S A. 2000 Jul 18;97(15):8623-8
10869443
J Biol Chem. 2000 Mar 3;275(9):6189-94
10692411
Biochemistry. 1994 Feb 22;33(7):1718-23
8110774
Exp Eye Res. 1986 Dec;43(6):929-40
2949994
PLoS Med. 2005 Nov;2(11):e333
16250670
J Biol Chem. 2008 Sep 26;283(39):26684-93
18658157
Mol Membr Biol. 2009 Jan;26(1):14-31
19191172
J Cell Biol. 2004 Feb 2;164(3):373-83
14745001
Vision Res. 2006 Dec;46(27):4493-501
16989884
Annu Rev Biochem. 2006;75:743-67
16756510
J Biol Chem. 1996 Mar 1;271(9):5215-24
8617805
Nat Genet. 2002 Oct;32(2):254-60
12219089
Exp Eye Res. 2001 Nov;73(5):735-7
11747373
Nature. 2003 Jan 9;421(6919):127-8
12520290
Methods Enzymol. 1995;250:348-61
7651164
J Biol Chem. 2000 Jan 21;275(3):1930-6
10636894
J Biol Chem. 1984 Apr 25;259(8):5054-7
6715336
Curr Pharm Des. 2006;12(14):1797-808
16712489
J Biol Chem. 1987 Apr 15;262(11):5210-5
3558391
FEBS Lett. 1988 Mar 28;230(1-2):1-5
3350146