Lin N, Bazan H E
Department of Ophthalmology, LSU Eye Center, Louisiana State University Medical Center School of Medicine, New Orleans 70112.
Curr Eye Res. 1992 Sep;11(9):899-907. doi: 10.3109/02713689209033487.
Protein kinase C (PKC) has been implicated in cell proliferation and differentiation. Multiple forms of PKC have been isolated, principally from the brain where PKC is most abundant. In rabbit corneal epithelium, two distinct major peaks of PKC activity were resolved by hydroxyapatite column chromatography. Peak 2, with 65% of the total PKC activity, corresponds to alpha-PKC, based on its mobility in the column and Western blot analysis using specific monoclonal antibodies. Peak 1 did not react with either polyclonal or monoclonal antibodies to PKC alpha-, beta-, and gamma-isoforms suggesting the presence of isoforms specific to the corneal epithelium, or of another member of the PKC family. To investigate possible changes in the amounts of the various PKC subspecies during wound healing, the enzyme activities of the isolated subspecies were assayed 2, 5, and 7 days after corneal de-epithelialization. Two days after wounding, by which time the migratory limbal epithelium had covered the denuded area, total PKC activity was unchanged but alpha-PKC activity had increased to 77% of the total activity, compared with 65% in non-wounded epithelium. An increased proportion of alpha-PKC activity was also observed 5 and 7 days after wounding, during which time proliferation of epithelium continued. We hypothesize that alpha-PKC plays a role in long-term responses after injury such as gene expression and corneal epithelial proliferation. Moreover, these studies indicate that the cornea provides a good model of in vivo wound healing for PKC studies.
蛋白激酶C（PKC）与细胞增殖和分化有关。已分离出多种形式的PKC，主要来自PKC含量最丰富的大脑。在兔角膜上皮中，通过羟基磷灰石柱色谱法分离出两个不同的主要PKC活性峰。基于其在柱中的迁移率以及使用特异性单克隆抗体的蛋白质印迹分析，峰2占总PKC活性的65%，对应于α-PKC。峰1与针对PKCα、β和γ亚型的多克隆或单克隆抗体均无反应，这表明存在角膜上皮特有的亚型，或PKC家族的另一个成员。为了研究伤口愈合过程中各种PKC亚型数量的可能变化，在角膜去上皮化后2、5和7天测定分离出的亚型的酶活性。受伤后两天，此时迁移的角膜缘上皮已覆盖裸露区域，总PKC活性未变，但α-PKC活性已增加至总活性的77%，而未受伤上皮中的这一比例为65%。在受伤后5天和7天也观察到α-PKC活性比例增加，在此期间上皮细胞继续增殖。我们假设α-PKC在损伤后的长期反应如基因表达和角膜上皮增殖中起作用。此外，这些研究表明角膜为PKC研究提供了一个良好的体内伤口愈合模型。
