Courtneidge S A, Dhand R, Pilat D, Twamley G M, Waterfield M D, Roussel M F
Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
EMBO J. 1993 Mar;12(3):943-50. doi: 10.1002/j.1460-2075.1993.tb05735.x.
The receptor for the macrophage colony stimulating factor-1 (CSF-1R) is a transmembrane glycoprotein with intrinsic tyrosine kinase activity. CSF-1 stimulation promotes the growth of cells of the macrophage lineage and of fibroblasts engineered to express CSF-1R. We show that CSF-1 stimulation resulted in activation of three Src family kinases, Src, Fyn and Yes. Concomitant with their activation, all three Src family kinases were found to associate with the ligand-activated CSF-1 receptor. These interactions were also demonstrated in SF9 insect cells co-infected with viruses encoding the CSF-1 receptor and Fyn, and the isolated SH2 domain of Fyn was capable of binding the CSF-1R in vitro. Analysis of mutant CSF-1Rs revealed that the 'kinase insert' (KI) domain of CSF-1R was not required for interactions with Src family kinases, but that mutation of one of the receptor autophosphorylation sites, Tyr809, reduced both their binding and enzymatic activation. Because fibroblasts expressing this receptor mutant are unable to form colonies in semi-solid medium or to grow in chemically defined medium in the presence of CSF-1, the Src family kinases may play a physiological role in the mitogenic response to CSF-1.
巨噬细胞集落刺激因子-1（CSF-1R）的受体是一种具有内在酪氨酸激酶活性的跨膜糖蛋白。CSF-1刺激可促进巨噬细胞谱系细胞以及经基因工程改造以表达CSF-1R的成纤维细胞的生长。我们发现，CSF-1刺激可导致三种Src家族激酶（Src、Fyn和Yes）的激活。与它们的激活相伴的是，发现所有这三种Src家族激酶都与配体激活的CSF-1受体相关联。在共同感染了编码CSF-1受体和Fyn的病毒的SF9昆虫细胞中也证实了这些相互作用，并且Fyn的分离的SH2结构域在体外能够结合CSF-1R。对突变型CSF-1R的分析表明，CSF-1R的“激酶插入”（KI）结构域对于与Src家族激酶的相互作用不是必需的，但是受体自身磷酸化位点之一Tyr809的突变会降低它们的结合以及酶促激活。由于表达这种受体突变体的成纤维细胞在半固体培养基中无法形成集落，或者在存在CSF-1的化学限定培养基中无法生长，因此Src家族激酶可能在对CSF-1的促有丝分裂反应中发挥生理作用。
