P562C, A NOVEL C2 DOMAIN PROTEIN OF LEUKOCYTES

白细胞NADPH氧化酶催化氧的产生 氧气和NADPH。酵母双杂交系统用于寻找 蛋白质与p67相互作用，p67是细胞内的一个亚基。 氧化物酶。该系统鉴定了一种编码a基因的B淋巴细胞基因。 含钙离子和脂结合C2结构域的56 kDa蛋白质 它的C末端的一半。RabPhilin-3A，一种与Rab3a结合的蛋白 在突触小泡运输中，具有类似的C2结构域结构， 提示这种命名为p56C2的新蛋白质并对其进行了表征 根据其在中性粒细胞和B淋巴细胞中的定位，其 与其他白细胞蛋白和皮质的相互作用 细胞骨架及其与血脂的关系。P56C2的功能 将通过检测其对体内氧化酶活性的影响来进行研究 磷酸化依赖的氧化酶激活系统，通过检查 耗竭细胞中的氧化酶激活和分泌囊泡融合 通过反义技术，并通过研究转基因 缺乏这种蛋白质的小鼠。我们将特别注意 P56C2与小鸟嘌呤Rap1A相互作用的可能性 与膜结合的核苷酸结合蛋白- 氧化酶的相关亚基。通过这些实验，我们 希望对O2的激活有更深入的了解- 白细胞的形成酶，在宿主防御中起重要作用的酶 以及炎症的有害副作用。

The leukocyte NADPH oxidase catalyzes the production of O2 from oxygen and NADPH. The yeast 2-hybrid system was used to look for proteins the interact with p67, one of the cytosolic subunits of the oxidase. This system identified a B lymphocyte cDNA that encoded a 56 kDa protein containing two Ca++ and lipid-binding C2 domains in its C-terminal half. Rabphilin-3A, a Rab3a-binding protein involved in synaptic vesicle trafficking, has a similar C2 domain structure, suggesting that the new protein, designated p56C2 and characterize it in terms of its location in neutrophils and B lymphocytes, its interactions with other leukocyte proteins and with the cortical cytoskeleton, and its association with lipids. The function of p56C2 will be studied by examining its effect on oxidase activation in the phosphorylation-dependent oxidase activating system, by examining oxidase activation and secretory vesicle fusion in cells depleted of the protein by antisense techniques, and by studying a transgenic mouse deficient in the protein. Particular attention will be paid to the possibility that p56C2 interacts with Rap1A, a small guanine nucleotide-binding protein that copurifies with the membrane- associated subunits of the oxidase. Through these experiments we hope to achieve a deeper understanding of the activation of the O2- forming oxidase of leukocytes, and enzyme important in host defense and in the harmful side effects of inflammation.