Vilgrain I, Chinn A, Gaillard I, Chambaz E M, Feige J J
Unité INSERM 244, Biochimie des Régulations Cellulaires Endocrines, Département de Biologie Moléculaire et Structurale, CEA, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
Biochem J. 1998 Jun 1;332 ( Pt 2)(Pt 2):533-40. doi: 10.1042/bj3320533.
A study of bovine adrenocortical cell shape on adrenocorticotropic hormone (ACTH) challenge showed that the cells round up and develop arborized processes. This effect was found to be (1) specific for ACTH because angiotensin II and basic fibroblast growth factor have no effect; (2) mediated by a cAMP-dependent pathway because forskolin reproduces the effect of the hormone; (3) inhibited by sodium orthovanadate, a phosphotyrosine phosphatase inhibitor, but unchanged by okadaic acid, a serine/threonine phosphatase inhibitor; and (4) correlated with a complete loss of focal adhesions. Biochemical studies of the focal-adhesion-associated proteins showed that pp125fak, vinculin (110 kDa) and paxillin (70 kDa) were detected in the Triton X-100-insoluble fraction from adrenocortical cells. During cell adhesion on fibronectin as substratum, two major phosphotyrosine-containing proteins of molecular masses 125 and 68 kDa were immunodetected in the same fraction. A dramatic decrease in the extent of tyrosine phosphorylation of these proteins was observed within 60 min after treatment with ACTH. No change in pp125fak tyrosine phosphorylation nor in Src activity was detected. In contrast, paxillin was found to be tyrosine-dephosphorylated in a time-dependent manner in ACTH-treated cells. Sodium orthovanadate completely prevented the effect of ACTH. These observations suggest a possible role for phosphotyrosine phosphatases in hormone-dependent cellular regulatory processes.
一项关于促肾上腺皮质激素（ACTH）刺激下牛肾上腺皮质细胞形态的研究表明，细胞会变圆并形成分支状突起。研究发现这种效应具有以下特点：（1）对ACTH具有特异性，因为血管紧张素II和碱性成纤维细胞生长因子无此作用；（2）由cAMP依赖性途径介导，因为福斯可林能重现该激素的作用；（3）被磷酸酪氨酸磷酸酶抑制剂原钒酸钠抑制，但丝氨酸/苏氨酸磷酸酶抑制剂冈田酸对其无影响；（4）与粘着斑的完全丧失相关。对粘着斑相关蛋白的生化研究表明，在肾上腺皮质细胞的Triton X - 100不溶性部分中检测到了pp125fak、纽蛋白（110 kDa）和桩蛋白（70 kDa）。在以纤连蛋白为底物的细胞粘附中，在同一部分中免疫检测到了两种主要的含磷酸酪氨酸的分子量分别为125和68 kDa的蛋白。在用ACTH处理后60分钟内，观察到这些蛋白的酪氨酸磷酸化程度显著降低。未检测到pp125fak酪氨酸磷酸化或Src活性的变化。相反，发现在ACTH处理的细胞中，桩蛋白以时间依赖性方式发生酪氨酸去磷酸化。原钒酸钠完全阻断了ACTH的作用。这些观察结果表明磷酸酪氨酸磷酸酶在激素依赖性细胞调节过程中可能发挥作用。
