Highly effective phosphorylation by G protein-coupled receptor kinase 7 of light-activated visual pigment in cones

被引:67
作者
Tachibanaki, S
Arinobu, D
Shimauchi-Matsukawa, Y
Tsushima, S
Kawamura, S
机构
[1] Osaka Univ, Grad Sch Sci, Grad Sch Frontier Biosci, Suita, Osaka 5650871, Japan
[2] Osaka Univ, Grad Sch Sci, Dept Biol, Suita, Osaka 5650871, Japan
关键词
rod; photoreceptors; retina; phototransduction;
D O I
10.1073/pnas.0501875102
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Cone photoreceptors show briefer photoresponses than rod photoreceptors. Our previous study showed that visual pigment phosphorylation, a quenching mechanism of light-activated visual pigment, is much more rapid in cones than in rods. Here, we measured the early time course of this rapid phosphorylation with good time resolution and directly compared it with the photoresponse time course in cones. At the time of photoresponse recovery, almost two phosphates were incorporated into a bleached cone pigment molecule, which indicated that the visual pigment phosphorylation coincides with the photoresponse recovery. The rapid phosphorylation in cones is attributed to very high activity of visual pigment kinase [G protein-coupled receptor kinase (GRK) 7] in cones. Because of this high activity, cone pigment is readily phosphorylated at very high bleach levels, which probably explains why cone photoresponses recover quickly even after a very bright light and do not saturate under intense background light. The high GRK7 activity is brought about by high content of a highly potent enzyme. The expression level of GRK7 was 10 times higher than that of rod kinase (GRK1), and the specific activity of a single GRK7 molecule was approximate to 10 times higher than that of GRK1. The specific activity of GRK7 is the highest among the GRKs so far known. Our result seems to explain the response characteristics of cone photoreceptors in many aspects, including the nonsaturation of the cone responses during daylight vision.
引用
收藏
页码:9329 / 9334
页数:6
相关论文
共 40 条
[31]  
SHICHI H, 1978, J BIOL CHEM, V253, P7040
[32]   Visual pigment: G-protein-coupled receptor for light signals [J].
Shichida, Y ;
Imai, H .
CELLULAR AND MOLECULAR LIFE SCIENCES, 1998, 54 (12) :1299-1315
[33]   RHODOPSIN KINASE PREPARED FROM BOVINE ROD DISK MEMBRANES QUENCHES LIGHT ACTIVATION OF CGMP PHOSPHODIESTERASE IN A RECONSTITUTED SYSTEM [J].
SITARAMAYYA, A .
BIOCHEMISTRY, 1986, 25 (19) :5460-5468
[34]   Activation of transducin by a Xenopus short wavelength visual pigment [J].
Starace, DM ;
Knox, BE .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1997, 272 (02) :1095-1100
[35]   Amino acid residues of S-modulin responsible for interaction with rhodopsin kinase [J].
Tachibanaki, S ;
Nanda, K ;
Sasaki, K ;
Ozaki, K ;
Kawamura, S .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (05) :3313-3319
[36]   Low amplification and fast visual pigment phosphorylation as mechanisms characterizing cone photoresponses [J].
Tachibanaki, S ;
Tsushima, S ;
Kawamura, S .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2001, 98 (24) :14044-14049
[37]  
Weiss E R, 1998, Mol Vis, V4, P27
[38]   Species-specific differences in expression of G-protein-coupled receptor kinase (GRK) 7 and GRK1 in mammalian cone photoreceptor cells: Implications for cone cell phototransduction [J].
Weiss, ER ;
Ducceschi, MH ;
Horner, TJ ;
Li, AM ;
Craft, CM ;
Osawa, S .
JOURNAL OF NEUROSCIENCE, 2001, 21 (23) :9175-9184
[39]   Prolonged photoresponses in transgenic mouse rods lacking arrestin [J].
Xu, J ;
Dodd, RL ;
Makino, CL ;
Simon, MI ;
Baylor, DA ;
Chen, J .
NATURE, 1997, 389 (6650) :505-509
[40]  
YAU KW, 1994, INVEST OPHTH VIS SCI, V35, P9