Protein Kinase C Gamma in the Lens

在晶状体中，缝隙连接活性因晶状体/神经特异性PKC伽马亚型的激活而降低。 这种酶被生长和压力因素激活，如IGF-1、LEDGF和过氧化氢。 一旦激活，PKC-γ转位到膜上，并磷酸化晶状体连接蛋白，如 Cx43。这通过将缝隙连接斑块分解成 含L小窝蛋白的质膜脂筏。这种PKC伽马功能可以保护晶状体免受 通过分解缝隙连接而产生的氧化应激和防止损伤信号传递到 邻近的细胞，这一过程可能发生在缺血期间。我们的假设是，PKC伽马作为 在镜头里安装了一个应力传感器。这种异构体对氧化和激活信号更敏感，如 二酰甘油，而不是其他经典的PKC亚型。因此，当它存在于细胞中时，它是主要的PKC传感器 压力。Pkc-γ基因敲除模型不能减少对氢的反应的缝隙连接。 过氧化氢和这一模型可能对导致白内障的氧化应激损伤更敏感。这个 旨在测试PKC伽马作为透镜应力传感器的作用的具体目标是：1.识别结构 镜头的PKC伽马的特点，使这是一个应力传感器。这将包括标识 对接蛋白质和识别位点，维持该酶处于非活性状态。2.确定PKC如何 通过鉴定蛋白质上的相互作用部位，GAMA与脂筏中的Cx43和小窝蛋白-1相互作用。3. 确定整个晶状体对过氧化氢胁迫的反应机制是通过激活 PKC-γ和Cx46、Cx50.4功能降低。确定GAP的PKC伽马控制 链脲佐菌素大鼠在糖尿病期间连接受到损害。5.评估PKC伽马基因敲除 用小鼠模型测定PKC-γ在整个晶状体应激反应中的作用。多肽将是 设计了一种可以从14-3-3对接蛋白中去除PKC-γ并激活PKC-γ的方法 镜头。这应该会导致缝隙连接的解体，并有助于防止氧化应激造成的损害。 这些多肽也可能有助于防止缺血对视网膜的损害。

In the lens gap junction activity is decreased by activation of the lens/neural-specific PKC gamma isoform. This enzyme is activated by growth and stress factors such as IGF-1, LEDGF, and by hydrogen peroxide. Upon activation PKC gamma translocates to membranes and phosphorylates lens connexin proteins such as Cx43. This causes inhibiton of gap junctions through disassembly of gap junction plaques into caveolin-l-containing plasma membrane lipid rafts. This PKC gamma function could protect the lens from oxidative stress through disassembly of gap junctions and prevention of the passage of damaging signals to neighboring cells, a process which can occur during ischemia. Our hypothesis is that PKC gamma serves as a stress sensor in the lens. This isoform is more sensitive to oxidative and activation signals such as diacylglycerol, than other classical PKC isoforms. Thus, when present in cells it is the major PKC sensor of stress. The PKC gamma knock-out model is not able to decrease gap junctions in response to hydrogen peroxide and this model may be more sensitive to oxidative stress damage which causes cataracts. The specific aims, designed to test the role of PKC gamma as a lens stress sensor are: 1. Identify structural features of the lens PKC gamma which allow this to be a stress sensor. This will include identification of the docking protein and recognition sites which maintain this enzyme in an inactive state. 2. Determine how PKC gamma interacts with Cx43 and caveolin-1 in lipid rafts by identification of interaction sites on the proteins. 3. Determine the mechanism by which whole lens responds to hydrogen peroxide stress through activation of PKC gamma and decreased function of Cx46 and Cx50.4. Determine how the PKC gamma control of gap junctions is compromised during diabetes in the streptozotocin rat. 5. Assess the PKC gamma knock-out mouse model to determine the role of PKC gamma in the whole lens stress response. Peptides will be designed which can remove the PKC gamma from the 14-3-3 docking protein and activate PKC gamma in lens. This should cause disassembly of gap junctions and help to prevent damage from oxidative stress. These peptides could also be useful to prevent damage to retina from ischemia.