Kumagai A, Okamoto K
J Biochem. 1985 Jul;98(1):1-7. doi: 10.1093/oxfordjournals.jbchem.a135247.
By the use of a shake culture system, we have previously shown (Oyama, M., Okamoto, K., & Takeuchi, I. (1982) J. Cell Sci. 56, 223-232) that both cAMP and cAMP-dependent cell contact are required for prespore differentiation in Dictyostelium discoideum. The present study was undertaken to examine changes of the plasma membrane proteins during prespore differentiation in the shake culture system. Rabbit antibodies prepared against the plasma membrane fraction of the differentiated cells inhibited the reaggregation of the differentiated cells but not that of aggregation-competent cells. This result indicates that new contact sites are formed in the differentiated cells. By the combined use of the antibody-conjugated immuno-adsorbent with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, changes of membrane proteins were analyzed with the cells incubated under various conditions. Three proteins were found to be present specifically in the differentiated cells only in the presence of cAMP, one of which (105K protein) appeared when cells became adhesive, but before prespore specific proteins were detected. Two others (80K and 58K proteins) appeared during prespore differentiation after cells formed agglomerates.
通过使用振荡培养系统，我们之前已经表明（Oyama, M., Okamoto, K., & Takeuchi, I. (1982) J. Cell Sci. 56, 223 - 232），环磷酸腺苷（cAMP）和依赖cAMP的细胞接触对于盘基网柄菌的前孢子分化都是必需的。本研究旨在检测振荡培养系统中前孢子分化过程中质膜蛋白的变化。针对分化细胞的质膜部分制备的兔抗体抑制了分化细胞的再聚集，但不抑制具有聚集能力的细胞的再聚集。这一结果表明在分化细胞中形成了新的接触位点。通过将抗体偶联免疫吸附剂与十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳相结合，分析了在各种条件下培养的细胞的膜蛋白变化。发现有三种蛋白质仅在存在cAMP的情况下特异性地存在于分化细胞中，其中一种（105K蛋白）在细胞变得具有黏附性时出现，但在检测到前孢子特异性蛋白之前。另外两种（80K和58K蛋白）在细胞形成聚集体后的前孢子分化过程中出现。
