Hatakeyama M, Minamoto S, Taniguchi T
Proc Natl Acad Sci U S A. 1986 Dec;83(24):9650-4. doi: 10.1073/pnas.83.24.9650.
Tac antigen, the receptor for human interleukin 2 (IL-2), contains in its intracytoplasmic region a serine residue (Ser-247) that is seemingly the predominant site of protein kinase C-mediated phosphorylation. A number of studies on growth factor receptors have suggested the importance of phosphorylation in receptor structure, function, and regulation. In this study, we generated site-directed mutations in the Tac antigen cDNA to generate mutant receptors in which Ser-247 or Thr-250, a probable site of minor phosphorylation, was replaced with another amino acid that is not accessible to phosphorylation. Study of the expression of these mutant genes in a T-lymphoid cell line has provided no evidence as to the essential role of the above-mentioned residues in determining the degree of receptor affinity, its ability for signal transduction, and phorbol ester-mediated regulation of the receptor. Our results strongly suggest the existence of an IL-2 receptor "complex" in which the Tac antigen is associated with another molecule(s) that is involved in receptor structure, function, and regulation.
Tac抗原是人类白细胞介素2（IL-2）的受体，其胞质区内含有一个丝氨酸残基（Ser-247），该残基似乎是蛋白激酶C介导的磷酸化的主要位点。对生长因子受体的多项研究表明，磷酸化在受体结构、功能和调节中具有重要作用。在本研究中，我们在Tac抗原cDNA中产生了定点突变，以生成突变受体，其中Ser-247或Thr-250（一个可能的次要磷酸化位点）被另一个无法进行磷酸化的氨基酸取代。对这些突变基因在T淋巴细胞系中的表达研究并未提供证据表明上述残基在决定受体亲和力程度、其信号转导能力以及佛波酯介导的受体调节方面的关键作用。我们的结果强烈表明存在一种IL-2受体“复合物”，其中Tac抗原与另一种参与受体结构、功能和调节的分子相关联。
