Sugawa H, Beniko M, Imura H, Mori T
Department of Laboratory Medicine, Kyoto University School of Medicine, Japan.
Biochem Biophys Res Commun. 1993 May 28;193(1):390-7. doi: 10.1006/bbrc.1993.1636.
A rat thyroid cell line FRTL-5 showed no significant binding of epidermal growth factor(EGF) either in the presence or absence of thyrotropin(TSH). Conditioned medium from FRTL-5 did not inhibit the specific binding of [125I]EGF to HeLa cell which has EGF receptors (EGF-R). Two bands of 170KD and 80KD obtained by immunoprecipitation with solubilized FRTL-5 and anti-EGF-R monoclonal antibody indicated autophosphorylation activity. The activity was enhanced by several thyroid cell growth factors including TSH. dibutyryl-cAMP(db-cAMP), insulin like growth factor I(IGF-I). Interleukin 1 beta (IL-1 beta) and phorbol ester. EGF alone enhanced the autophosphorylation activity. These data indicate that FRTL-5 possesses unique EGF-R with low affinity to EGF and that the tyrosine kinase of the receptor is activated during cell proliferation.
大鼠甲状腺细胞系FRTL-5在有或无促甲状腺激素（TSH）存在的情况下，均未显示出明显的表皮生长因子（EGF）结合。FRTL-5的条件培养基不抑制[125I]EGF与具有EGF受体（EGF-R）的HeLa细胞的特异性结合。用溶解的FRTL-5和抗EGF-R单克隆抗体进行免疫沉淀得到的170KD和80KD两条带显示出自身磷酸化活性。包括TSH、二丁酰环磷腺苷（db-cAMP）、胰岛素样生长因子I（IGF-I）、白细胞介素1β（IL-1β）和佛波酯在内的几种甲状腺细胞生长因子可增强该活性。单独的EGF也能增强自身磷酸化活性。这些数据表明，FRTL-5拥有对EGF亲和力低的独特EGF-R，并且该受体的酪氨酸激酶在细胞增殖过程中被激活。
