Lazo P A, Cuevas L, Gutierrez del Arroyo A, Orúe E
Unidad de Genética y Medicina Molecular (Consejo Superior de Investigaciones Científicas), Instituto de Salud Carlos III, Majadahonda, Spain.
Cell Immunol. 1997 Jun 15;178(2):132-40. doi: 10.1006/cimm.1997.1139.
The CD53 antigen is a member of the tetraspan family of proteins with unknown function. Stimulation of rat IR938F B-cell lymphoma cells with monoclonal antibody MRC OX44 (anti-rat CD53) triggered a homotypic adhesion reaction which reached a maximum effect at 24 hr. This effect occurred at 37 degrees C but not at 4 degrees C. Adhesion was prevented by removal of divalent cations, Ca2+ and Mg2+, with EGTA and EDTA as chelating agents. The adhesion induced by MRC OX44 was inhibited by cycloheximide and actinomycin D, suggesting that de novo protein synthesis was required for this effect. The addition of mAb WT1 against rat LFA-1 (CD11a) antigen had no effect on adhesion, suggesting that the cell-cell interaction is not mediated by the expression of LFA-1 antigen. The intracellular signals required to induce adhesion were inhibited by two tyrosine kinase inhibitors, genistein and piceatannol. Wortmannin, a selective inhibitor of phosphoinositide 3-kinase activity, completely blocked adhesion. Two protein kinase C inhibitors, H7 and bisindolylmaleimide, inhibited the adhesion, suggesting that part of the signal is mediated by PKC. Electron microscopy of aggregated cells showed that the interaction is localized to short membrane regions, where contact areas of higher density in opposing zones from both cells were detected. We postulate that there is a common adhesion mechanism that is modulated by several tetraspan family members and associated proteins. This adhesion structure might represent a novel form of cell communication among lymphoid cells.
CD53抗原是功能未知的四跨膜蛋白家族成员。用单克隆抗体MRC OX44（抗大鼠CD53）刺激大鼠IR938F B细胞淋巴瘤细胞会引发同型黏附反应，该反应在24小时时达到最大效应。此效应在37℃时出现，但在4℃时不出现。用EGTA和EDTA作为螯合剂去除二价阳离子Ca2+和Mg2+可阻止黏附。MRC OX44诱导的黏附受到环己酰亚胺和放线菌素D的抑制，这表明这种效应需要从头合成蛋白质。添加抗大鼠LFA-1（CD11a）抗原的单克隆抗体WT1对黏附没有影响，这表明细胞间相互作用不是由LFA-1抗原的表达介导的。诱导黏附所需的细胞内信号受到两种酪氨酸激酶抑制剂染料木黄酮和白皮杉醇的抑制。渥曼青霉素是一种磷酸肌醇3激酶活性的选择性抑制剂，它完全阻断了黏附。两种蛋白激酶C抑制剂H7和双吲哚马来酰胺抑制了黏附，这表明部分信号是由蛋白激酶C介导的。对聚集细胞的电子显微镜观察表明，这种相互作用局限于短的膜区域，在来自两个细胞相对区域中检测到更高密度的接触区域。我们推测存在一种由几个四跨膜家族成员和相关蛋白调节的共同黏附机制。这种黏附结构可能代表了淋巴细胞间一种新型的细胞通讯形式。
