TYROSINE PHOSPHORYLATION AND MAMMALIAN RETINA

通过细胞内酪氨酸磷酸化的信号是一个不可或缺的 包括生长在内的许多正常和异常细胞过程的组成部分， 分化、增殖、维持和存活。初始 在非眼组织中的这些信号级联中的事件涉及刺激 介导的酪氨酸激酶活化。酪氨酸的研究进展 哺乳动物视网膜中的磷酸化显示：1）光 刺激光感受器外节蛋白的酪氨酸磷酸化， 2)来自光适应视网膜的视杆细胞外段（ROS）富含 酪氨酸激酶c-Src、PLC γ/1和阻滞剂，3）至少三种 假定的酪氨酸激酶底物存在于分离的ROS中 磷脂酶C（PLC γ/1），磷脂酰肌醇3-激酶（PI 3-激酶） 和酪氨酸磷酸酶Syp）和4）光诱导的变化， PLC γ/1从内段到外段的定位 与酪氨酸磷酸化增加一致的光受体 在ROS。基于这些观察，我们假设光刺激 c-Src通过诱导其酪氨酸残基上的自磷酸化来表达。的 C-Src上的磷酸酪氨酸（P-Y）残基可以与Src结合 存在于其他光感受器信号传导中的同源区（SH 2）结构域 蛋白质（例如PLC γ/1、PI 3-激酶和酪氨酸磷酸酶Syp） 或与其他蛋白质上的磷酸酪氨酸结合结构域（PTB）结合， 这些蛋白质的酪氨酸磷酸化和随后的转运或 易位到外节。当前应用程序的目标 要确定：1.随后的运输或转移到外部 片段当前应用程序的目标是确定：1。如果c- SRC是大鼠感光细胞/视杆细胞中的一种光激活酪氨酸激酶 体内外节（ROS）; 2.主要蛋白质的身份 光感受器中酪氨酸磷酸化的底物 体内细胞;和3.如果体内酪氨酸磷酸化促进了 特异性蛋白质转运至光感受器ROS。几种不同 体内方法包括生物化学、免疫学和细胞化学 将利用各种技术来实现这些具体目标。我们提出 体内光介导的酪氨酸磷酸化可能在 维持功能或结构极化 感光细胞，这可能有助于整体维护， 这些细胞的存活。

Signaling through intracellular tyrosine phosphorylation is an integral component of many normal and aberrant cellular processes including growth, differentiation, proliferation, maintenance and survival. The initial event in these signaling cascades in non-ocular tissues involves stimulus mediated activation of a tyrosine kinase. Our studies on tyrosine phosphorylation in mammalian retinas in vivo show that: 1) light stimulates tyrosine phosphorylation of photoreceptor out segment proteins, 2) rod outer segments (ROS) from light-adapted retinas are enriched with the tyrosine kinase c-Src,PLCgamma/1, and arresting, 3) at least three putative tyrosine kinase substrates are present in isolated ROS (Phospholipase C (PLCgamma/1), Phosphatidylinositol 3-kinase (PI 3-kinase) and the tyrosine phosphatase Syp) and 4) light induces a changes in the localization of PLCgamma/1 from the inner to the outer segment of photoreceptors that is coincident with increased tyrosine phosphorylation in ROS. Based on these observations, we hypothesize that light stimulates c-Src by inducing its autophosphorylation on tyrosine residues. The phosphotyrosine (P-Y) residues on C-Src can then associated with Src homology regions (SH2) domains present in other photoreceptor signaling proteins (e.g. PLCgamma/1, PI 3-kinase and the tyrosine phosphatase Syp) or with phosphotyrosine binding domains (PTB) on other proteins leading to tyrosine phosphorylation of these proteins and subsequent transport or translocation to the outer segment. The goals of the current application are to determine: 1. subsequent transport or translocation to the outer segment. The goals of the current application are to determine: 1. if c- Src is a light-activated tyrosine kinase in rat photoreceptor cells/ rod outer segment (ROS) in vivo; 2. the identities of the major protein substrates that are tyrosine phosphorylated by light in photoreceptor cells in vivo; and 3. if tyrosine phosphorylation in vivo promotes the translocation of specific proteins to photoreceptor ROS. Several different in vivo approaches including biochemical, immunological and cytochemical techniques will be utilized in addressing these specific aims. We propose that in vivo light-mediated tyrosine phosphorylation may play a role in the maintenance of the functional or structural polarization of photoreceptor cells which may contribute to the overall maintenance and survival of these cells.