Yoshida Motonobu, Sakuragi Naoya, Kondo Ken, Tanesaka Eiji
Department of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
Comp Biochem Physiol B Biochem Mol Biol. 2006 Feb;143(2):138-44. doi: 10.1016/j.cbpb.2005.10.006. Epub 2006 Jan 4.
A cell adhesion molecule, 80-kDa csA, is involved in EDTA-resistant cell contact at the aggregation stage of Dictyostelium discoideum. A 31-kDa csA was isolated from the 80-kDa csA by treatment with Achromobacter protease I. Results from thin-layer chromatography and MALDI-TOF MS analysis indicated that the 31-kDa csA contains ceramide as a component of glycosylphosphatidyl-inositol (GPI). Comparison between the 80-kDa csA and the 31-kDa csA treated with phosphatidylinositol-specific phospholipase C (PI-PLC) or GPI-specific phospholipase D (GPI-PLD) was carried out. Our results indicated that the GPI-anchor of the 31-kDa csA was more sensitive to PI-PLC treatment than that of the 80-kDa csA, and that the anchor in both was easily cleaved by GPI-PLD treatment. They suggested that the resistance of 80-kDa csA to PI-PLC treatment was due to steric hindrance and myo-inositol modification. The results of the 80-kDa csA and the 31-kDa csA treated with sphingomyelinase were similar to those with PI-PLC treatment. In the presence of 1,10-phenanthroline, a GPI-PLD inhibitor, development of Dictyostelium was markedly inhibited, suggesting that GPI-PLD is functional in developmental regulation through cell adhesion.
一种细胞黏附分子，80 kDa的csA，在盘基网柄菌聚集阶段参与抗EDTA的细胞接触。通过无色杆菌蛋白酶I处理从80 kDa的csA中分离出一种31 kDa的csA。薄层色谱和基质辅助激光解吸电离飞行时间质谱分析结果表明，31 kDa的csA含有神经酰胺作为糖基磷脂酰肌醇（GPI）的一个组成部分。对用磷脂酰肌醇特异性磷脂酶C（PI-PLC）或GPI特异性磷脂酶D（GPI-PLD）处理的80 kDa的csA和31 kDa的csA进行了比较。我们的结果表明，31 kDa的csA的GPI锚对PI-PLC处理比80 kDa的csA更敏感，并且两者的锚都很容易被GPI-PLD处理切割。结果表明，80 kDa的csA对PI-PLC处理的抗性是由于空间位阻和肌醇修饰。用鞘磷脂酶处理80 kDa的csA和31 kDa的csA得到的结果与用PI-PLC处理的结果相似。在GPI-PLD抑制剂1,10-菲咯啉存在的情况下，盘基网柄菌的发育受到显著抑制，这表明GPI-PLD通过细胞黏附在发育调控中发挥作用。
