PHOTORECEPTION AND TRANSDUCTION IN VISION

描述（改编自申请人的摘要）：长期目标 这项研究旨在确定视觉信号的分子基础， 哺乳动物的视锥光感受器具体目标是检查潜在的 三种选择性视锥细胞信号传导功能的机制差异 视锥细胞视色素，视锥细胞 cGMP磷酸二酯酶和锥鸟苷酸环化酶。视觉 将检查颜料的漂白特性、 转导蛋白和与抑制蛋白的相互作用。的cGMP 将评估磷酸二酯酶的内在活性、非催化活性 cGMP控制活性，G蛋白控制激活和关闭， 关闭.将检查鸟苷酸环化酶的内在差异。 活性和调节酶活性的机制。生化 寻找可能解释为什么哺乳动物的视锥细胞 敏感，高血压更迅速与较小的振幅，并适应 在较大的光通量范围内，信号形状几乎没有变化 与杆反应相比。

DESCRIPTION (Adapted from applicant's abstract): The long term goal of this research is to define the molecular basis of visual signaling in mammalian cone photoreceptors. Specific aims are to examine potential mechanistic differences in function of three selected cone signaling components compared to those in rods: the cone visual pigments, the cone cGMP phosphodiesterase, and the cone guanylyl cyclases. The visual pigments will be examined for their bleaching profile, activation of transducins, and interactions with arrestins. The cGMP phosphodiesterase will be assessed for intrinsic activity, non-catalytic cGMP control of activity, and G-protein control of activation and shut- off. The guanylyl cyclases will be examined for differences in intrinsic activity and mechanisms that regulate enzymatic activity. Biochemical mechanisms are sought that might explain why mammalian cones are less sensitive, hyperpolarize more rapidly with smaller amplitudes, and adapt over a larger range of light fluence with little change in signal shape in comparison with rod responses.