The role of proteins belonging to a plastin gene family in host defenses against bacterial infections.

我们以前确定了一个65 kDa的蛋白质（p65），在活化的巨噬细胞磷酸化。它已被证明是人类L-plastin的小鼠同源物，被鉴定为人类癌细胞中的新型蛋白质。P65/L-plastin具有一系列Ca^2+、钙调蛋白和肌动蛋白结合结构域，被认为在白细胞和癌细胞中起关键作用。我们在大肠杆菌中表达了重组γ p65/L-plastin。大肠杆菌中的蛋白质结合b-肌动蛋白，并使用大量的蛋白质作为免疫原制备高滴度抗体。抗rp 65/L-plastin抗体识别天然p65/L-plastin以及rp 65/L-plastin，并使我们能够检测细胞内p65/L-plastin的精细结构，并且发现其定位通过细菌组分的刺激而广泛改变。我们进一步开发了一种酶联免疫吸附测定系统和流式细胞术方法，使用这些试剂，这使得有可能测量抗体，包括对p65/L-plastin的自身抗体，并评估白细胞中蛋白质的成熟依赖性表达。

We previously identified a 65-kDa protein (p65) that was phosphorylated in activated macrophages. It has turned out to be a murine homologue of human L-plastin that was identified as a novel protein in human cancer cells. P65/L-plastin is characterized by a series of Ca^<2+>-, calmodulin- and actin-binding domains, and is thought to play a crucial role in leukocytes and cancer cells. We have expressed a recombinant γ p65/L-plastin in E. coli that binds to b-actin and prepared high-titer antibodies using large amounts of the protein as immunogen. Anti-rp65/L-plastin antibodies recognize native p65/L-plastin as well as rp65/L-plastin and have enabled us to detect fine structures of intracellular p65/L-plastin, and it was found that its localization was extensively changed by stimulation with bacterial components. We further developed an enzyme-linked immunosorbent assay system and a flow cytometry method using these reagents, which made it possible to measure antibodies including autoantibodies against p65/L-plastin and to evaluate the maturation-dependent expression of the protein in leukocytes.