Wolfe P C, Chang E Y, Rivera J, Fewtrell C
Department of Pharmacology, Cornell University, Ithaca, New York 14853, USA.
J Biol Chem. 1996 Mar 22;271(12):6658-65. doi: 10.1074/jbc.271.12.6658.
Adhesion of RBL-2H3 mucosal mast cells to fibronectin-coated surfaces has been linked to changes in secretion and tyrosine kinase activity. We now show that adhesion affects the sensitivity of RBL cells to the protein kinase C activator phorbol 12-myristate 13-acetate (PMA). In suspended cells, PMA inhibited antigen-induced calcium influx (as measured by manganese influx) and changes in intracellular free calcium and had complex effects on antigen-stimulated secretion. However, in adherent cells PMA had little effect on these responses. Suspended cells only secreted in response to thapsigargin if they were co-treated with PMA, while adherent cells secreted in response to thapsigargin alone. The thapsigargin-induced secretion in adherent cells was inhibited by protein kinase C down-regulation and by the protein kinase C inhibitor GF 109203X, but not by calphostin C. We suggest that protein kinase C is constitutively activated in adherent cells, possibly due to modification of the regulatory domain of the enzyme.
RBL - 2H3黏膜肥大细胞与纤连蛋白包被表面的黏附与分泌及酪氨酸激酶活性的变化有关。我们现在表明，黏附会影响RBL细胞对蛋白激酶C激活剂佛波酯12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）的敏感性。在悬浮细胞中，PMA抑制抗原诱导的钙内流（通过锰内流测量）以及细胞内游离钙的变化，并对抗原刺激的分泌有复杂的影响。然而，在贴壁细胞中，PMA对这些反应几乎没有影响。悬浮细胞只有在与PMA共同处理时才会对毒胡萝卜素产生分泌反应，而贴壁细胞单独对毒胡萝卜素就会产生分泌反应。贴壁细胞中由毒胡萝卜素诱导的分泌受到蛋白激酶C下调以及蛋白激酶C抑制剂GF 109203X的抑制，但不受钙磷蛋白C的抑制。我们认为蛋白激酶C在贴壁细胞中被组成性激活，可能是由于该酶调节域的修饰。
