INFLUENCE OF PROTEIN/LIPID INTERACTIONS ON SIGNAL TRANSD

G蛋白偶联受体无处不在 信号转导系统的组件。这个项目是专门设计的 多不饱和磷脂在调节血糖中的作用 蛋白偶联信号转导及其机制的研究 乙醇在这些体系中的作用机理。视觉效果 杆状感光器中的转导通路，一个典型的G 蛋白质偶联系统，被用作模型系统。这个 脂质成分对：形成的动力学和程度的影响 后视紫红质II(MII)，视紫红质的G蛋白激活形式； MII/G蛋白复合体形成；G蛋白活化率； CGMP磷酸二酯酶(PDE)激活；GTP酶 G蛋白的活性正在研究中。以及 转导途径、酰链堆积中的功能措施 磷脂双层的性质正在通过使用来确定 时间分辨荧光光谱学。与世隔绝和 视紫红质在特定脂类双层中的重组 组合物允许评价磷脂酰基的作用 链组成。在目前的研究中，视紫红质、G蛋白和 PDE重组为磷脂双层膜，由 16：0、18：1 PC或16：0、22：6 PC，并与本机磁盘进行比较 G蛋白和PDE重新结合的膜。在… 低刺激水平，激活的视紫红质是 需要获得同等水平的光刺激的PDE活性 由16：0、18：1 PC组成的双层相对于由 16：0，22：6 PC。这些结果表明，增强的 在多不饱和化合物中观察到活性视紫红质的形成 磷脂沿着转导途径向下传播， 从而导致效应器酶PDE的活性水平更高。 许多神经递质受体是 G蛋白偶联受体超家族。因此减少了 视网膜和视网膜磷脂中的多不饱和酰基链 神经元组织可以预期导致低于最佳受体 功能。我们对视觉通路的观察表明，有些人 Omega-3中观察到的认知和视觉缺陷的一部分 有缺陷的动物是由于信号系统受损而导致的 由于膜磷脂中22：6N3链的丢失。

G protein-coupled receptors are ubiquitous components of signal transduction systems. This project is designed to assess the role of polyunsaturated phospholipids in modulating G protein- coupled signal transduction and to elucidate of the mechanism of action of ethanol in these systems. The visual transduction pathway in the rod photoreceptor, a prototypical G protein- coupled system, is being used as a model system. The effect lipid composition on: the kinetics and extent of formation of metarhodopsin II (MII), the G protein activating form of rhodopsin; MII/G protein complex formation; the rate of G protein activation; cGMP phosphodiesterase (PDE) activation; and the GTPase activity of the G protein are being studied. Along with the functional measures in the transduction pathway, acyl chain packing properties of the phospholipid bilayer are being determined by use of time-resolved fluorescence spectroscopy. The isolation and reconstitution of rhodopsin into bilayers of defined lipid composition allows an evaluation of the role of phospholipid acyl chain composition. In the current studies, rhodopsin, G protein, and PDE were reconstituted into phospholipid bilayers composed of 16:0, 18:1 PC or 16:0, 22:6 PC and compared to native disk membrane to which the G protein and PDE were reassociated. At low stimulus levels, twice as much activated rhodopsin was required to obtain equal levels of the light stimulated PDE activity bilayers composed of 16:0, 18:1 PC relative to those composed of 16:0, 22:6 PC. These results demonstrate that the enhanced formation of activated rhodopsin observed in polyunsaturated phospholipids is propagated down the transduction pathway, resulting in higher activity levels in the effector enzyme, PDE. Many of the neurotransmitter receptors are members of the superfamily of G protein-coupled receptors. Thus reductions of polyunsaturated acyl chains in the phospholipids in retinal and neuronal tissue can be expected to result in below optimal receptor function. Our observations in the visual pathway indicate that some part of the observed cognitive and visual deficits in omega-3 deficient animals arises from impaired signaling systems, resulting from the loss of 22:6n3 chains in membrane phospholipids.