Protein Kinase C Gamma in the Lens

描述（由申请方提供）：在透镜中，间隙连接活性因透镜/神经特异性PKC γ亚型的激活而降低。这种酶被生长和应激因子如IGF-1、LEDGF和过氧化氢激活。激活后，PKC γ易位至膜并磷酸化透镜连接蛋白，如Cx43。这导致通过将间隙连接斑块分解成含有小窝蛋白-1的质膜脂筏而形成间隙连接。这种PKC γ功能可以通过间隙连接的分解和防止损伤信号传递到邻近细胞来保护透镜免受氧化应激，这是在缺血期间可能发生的过程。我们的假设是PKC γ在透镜中充当应力传感器。这种同工型比其他经典的PKC同工型对氧化和活化信号（如二酰基甘油）更敏感。因此，当存在于细胞中时，它是压力的主要PKC传感器。PKC γ敲除模型不能减少间隙连接对过氧化氢的反应，并且该模型可能对导致白内障的氧化应激损伤更敏感。具体的目的，旨在测试PKC γ作为透镜应力传感器的作用是：1。识别结构 透镜PKC gamma的特征，其允许这是应力传感器。这将包括鉴定对接蛋白和识别位点，其使该酶保持在非活性状态。2.通过鉴定蛋白质上的相互作用位点，确定PKC γ如何与脂筏中的Cx43和小窝蛋白-1相互作用。3.确定整个透镜通过激活PKC γ和降低Cx46和Cx 50的功能对过氧化氢应激作出反应的机制。4.确定链脲佐菌素大鼠糖尿病期间间隙连接的PKC γ控制如何受损。5.评估PKC γ基因敲除小鼠模型，以确定PKC γ在整个透镜应激反应中的作用。将设计能够从14-3-3对接蛋白去除PKC γ并激活透镜中的PKC γ的肽。这应该会导致间隙连接的分解，并有助于防止氧化应激造成的损害。这些肽也可用于预防缺血对视网膜的损伤。

DESCRIPTION (provided by applicant): 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-1-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.