Reynhout J K, Lampe P D, Johnson R G
Department of Biological Sciences, Bethel College, St. Paul, Minnesota 55112.
Exp Cell Res. 1992 Feb;198(2):337-42. doi: 10.1016/0014-4827(92)90388-o.
Currently little is known about the regulation of gap junction communication in the lens. We report here on the effects of the protein kinase C activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), on cultured bovine lens cells which appeared to be epithelial in nature. Dramatically reduced intercellular transfer of the fluorescent dye Lucifer yellow was observed when the cultured lens cells were treated with octanol, a known inhibitor of gap junction communication. TPA (4 beta isomer) was also shown to reduce intercellular permeability within these cultures. In contrast, an inactive form of TPA, 4 alpha-TPA, did not decrease dye transfer. Permeability was evaluated in terms of both the number of cells receiving dye and the rate of decrease in fluorescence intensity in the injected cell. The maximum decreases in dye transfer occurred at 2 h of TPA treatment and dye transfer gradually increased to control levels over a time course of many hours. Incubation of cultures with 32Pi and immunoprecipitation using antibodies to the N- and C-terminal regions of connexin43 demonstrated a gap junction phosphoprotein of 43,000 Da. Phosphorylation of connexin43 increased during the first 2 h of TPA treatment. These results suggest that protein kinase C has a direct or indirect effect on gap junction communication in cultured lens cells.
目前，对于晶状体中缝隙连接通讯的调节机制知之甚少。我们在此报告蛋白激酶C激活剂12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）对培养的牛晶状体细胞的影响，这些细胞似乎具有上皮细胞的性质。当用已知的缝隙连接通讯抑制剂辛醇处理培养的晶状体细胞时，观察到荧光染料路西法黄的细胞间转移显著减少。TPA（4β异构体）也被证明可降低这些培养物中的细胞间通透性。相比之下，TPA的无活性形式4α - TPA并没有减少染料转移。通透性通过接受染料的细胞数量和注射细胞中荧光强度的降低速率来评估。染料转移的最大减少发生在TPA处理2小时时，并且在数小时的时间过程中染料转移逐渐增加至对照水平。用32Pi培养细胞并用针对连接蛋白43的N端和C端区域的抗体进行免疫沉淀，证实了一种43,000 Da的缝隙连接磷蛋白。在TPA处理的前2小时内，连接蛋白43的磷酸化增加。这些结果表明蛋白激酶C对培养的晶状体细胞中的缝隙连接通讯有直接或间接的影响。
