Comparative Study on Molecular Mechanism of Photoreception in the Retina and Pineal Gland

视网膜与松果体感光分子机制的比较研究

• 批准号: 05454027
• 负责人: FUKADA Yoshitaka
• 金额: $ 3.84万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05454027/
• 关键词: Rod; Cone; Pineal Gland; Photon-Signal Transduction; Photoreceptor Protein; Pinopsin; G-Protein; Transducin; 光情報伝達; ロドプシン; 脂肪酸修飾; 慨日リズム; 脂質修飾; メチル化

Many vertebrates have several types of photoreceptive cells ; rods and cones in the retina, and pinealocytes in the pineal gland. It is important to understand the difference in molecular mechanism responsible for the diverged cellular functions ; that is, rods for scotopic vision, cones for color vision, and pinealocytes for circadian regulation of biological clock. This project aimed at comparative studies on the photon-signal transduction processes in the three types of photoreceptive cells, particularly at the structures and functions of photoreceptive pigments and signal-transducing G-proteins in the cells.[Rod] To identify the physiological roles of lipid modifications of transducin alpha-and betagamma-subunits (Talpha and Tbetagamma), we studied the mechanism of the subunit interaction and the membrane association. It ws clearly shown that the isoprenyl and methyl groups of Tgamma regulate the efficiency of photon-signal transduction by affecting 1) Talpha-Tbetagamma coupling th … More rough direct contact with alpha-subunit, and 2) the interaction between transducin and cellular membranes. Monoclonal antibodies recognizing the structure of the N-terminal fatty acid of Talpha stained almost all of the rod outer segments in a bovine retina, suggesting that a single rod cell contains the four isoforms of Talpha modified with four kinds of fatty acids. The target of recoverin was shown to be rhodopsin kinase. The complex of calcium-recoverin-rhodopsin kinase was stabilized by the membrane association, by which the kinase activity was effectively inhibited.[Cone] Comparative studies on cone and rod photoreceptive pigments by low temperature spectroscopy, laser flash photolysis, and circular dichroism showed that the life times of the active intermediates of cone pigments are much faster than that of rhodopsin. This clearly indicates that the molecular property of cone pigment is one of the major determinants for physiological photoresponse of cones. Photochemical reactions of chimeric mutants composed of rod-and cone-type pigments demonstrated that the structures of helices 1 through 3 determines the life time of the active intermediate of photoreceptive pigments.[Pinealocytes] Little is known about the photon-signal transduction process in a photosensitive pineal gland. We found opsin-like immunoreaction in the gland by immunohistochemistry. Then we isolated the cDNA encoding a pineal specific opsin-like protein. Reconstitution experiment with 11-cis-retinal revealed its blue-light sensitivity, and thus we named it "pinopsin" after pineal opsin. This is the first demonstration of an opsin expressed in non-retinal tissues. Less

许多脊椎动物有几种类型的感光细胞;视网膜中的视杆细胞和视锥细胞，以及松果体中的松果体细胞。重要的是要了解不同的细胞功能的分子机制的差异，即暗视觉，视锥细胞的颜色视觉，和松果体细胞的生物钟的昼夜调节。本项目旨在比较研究三种光感受细胞的光-信号转导过程，特别是光感受色素和信号转导G蛋白的结构和功能。[Rod]为了确定转导素α和β γ亚基（Talpha和Tbetagamma）的脂质修饰的生理作用，我们研究了亚基相互作用和膜缔合的机制。它清楚地表明，异戊二烯基和甲基基团的T γ调节的光信号转导效率，通过影响1）α-T β γ耦合， ...更多信息 与α-亚基的粗糙直接接触; 2）转导素与细胞膜之间的相互作用。单克隆抗体识别的N-末端脂肪酸的Talpha染色的牛视网膜中几乎所有的杆外段的结构，这表明一个单一的杆细胞包含四种异构体的Talpha修饰与四种脂肪酸。recoverin的作用靶点是视紫红质激酶。钙恢复素-视紫红质激酶复合物的膜结合稳定了视紫红质激酶的活性，有效地抑制了视紫红质激酶的活性。[锥]通过低温光谱、激光闪光光解和圆二色性对锥和棒感光色素的比较研究表明，锥色素的活性中间体的寿命比视紫红质的寿命快得多。这清楚地表明，视锥色素的分子特性是决定视锥细胞生理光反应的主要因素之一。由棒状和锥形色素组成的嵌合突变体的光化学反应表明，螺旋1至3的结构决定了感光色素活性中间体的寿命。[松果体细胞]对感光松果体中的光子信号转导过程知之甚少。免疫组化结果显示，腺内有视蛋白样免疫反应。然后我们分离了编码松果体特异性视蛋白样蛋白的cDNA。用11-顺式-视黄醛重建实验表明，它对蓝光敏感，因此我们以松果体视蛋白命名为“pinopsin”。这是第一次证明视蛋白在非视网膜组织中表达。少

项目成果

Yoshinori Shichida: "Nanosecond laser photolysis of iodopsin,a chicken red-sensitive cone visual pigment." Biochemistry. 32. 10832-10838 (1993)

Yoshinori Shichida：“碘紫红质的纳秒激光光解，碘紫红质是一种鸡红色敏感的视锥视觉色素。”

Satoshi Tamotsu: "Localization of iodopsin and rod-opsin immunoreactivity in the retina and pineal complex of the river lamprey,Lampetra japonica." Cell Tissue Res.278. 1-10 (1994)

Satoshi Tamotsu：“七鳃鳗视网膜和松果体复合体中碘紫红质和视杆细胞视蛋白免疫反应性的定位。”

D.Kojima, H.Imai, T.Okano, Y.Fukada, F.Crescitelli, T.Yoshizawa and Y.Shichida: "Purification and low temperature spectroscopy of gecko visual pigments green and blue." Biochemistry. 34. 1096-1106 (1995)

D.Kojima、H.Imai、T.Okano、Y.Fukada、F.Crescitelli、T.Yoshizawa 和 Y.Shichida：“壁虎视色素绿色和蓝色的纯化和低温光谱。”

K.Sanada, T.Takao, Y.Shimonishi, T.Yoshizawa and Y.Fukada.: "Role of heterogeneous N-terminal acylation of recoverin in rhodopsin phosphorylation." J.Biol.Chem.270. 15459-15462 (1995)

K.Sanada、T.Takao、Y.Shimonishi、T.Yoshizawa 和 Y.Fukada.：“恢复蛋白异质 N 末端酰化在视紫红质磷酸化中的作用”。

T.Okano and Y.Fukada: "Brain is the third eye." Newton. 15. 102-107 (1995)

T.Okano 和 Y.Fukada：“大脑是第三只眼。”