Critical proline residues of the cytoplasmic domain of the IL-5 receptor alpha chain and its function in IL-5-mediated activation of JAK kinase and STAT5
Critical proline residues of the cytoplasmic domain of the IL-5 receptor alpha chain and its function in IL-5-mediated activation of JAK kinase and STAT5
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DOI：
10.1093/intimm/8.2.237
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发表时间：
1996-02-01
影响因子：
4.4
通讯作者：
Takatsu, K
中科院分区：
文献类型：
--
作者：
Kouro, T;Kikuchi, Y;Takatsu, K
IL-5的高亲和力受体（R）由独特的α链（IL-5 R α）和β链（β c）组成，所述β链与IL-3和粒细胞巨噬细胞集落刺激因子（GM-CSF）的受体共享。我们确定了IL-5诱导的增殖反应、核原癌基因表达和细胞蛋白质（包括β c、含SH 2/SH 3蛋白和JAK 2激酶）酪氨酸磷酸化的IL-5 R α的两个区域。在这里描述的研究中，我们证明了IL-3或GM-CSF刺激诱导JAK 2的酪氨酸磷酸化，并且在较小程度上诱导JAK 1和STAT 5的酪氨酸磷酸化。突变分析显示，IL-5 R α胞质结构域的膜近端脯氨酸富集序列（Pro352-Pro353-X-Pro355）中的一个脯氨酸残基，特别是Pro352和Pro355，是细胞增殖以及JAK 1和JAK 2激活所必需的。此外，表达由IL-5 R α的细胞外结构域和β c的细胞质结构域组成的嵌合受体的转染子对IL-5的增殖和JAK 1的酪氨酸磷酸化作出反应。有趣的是，电泳迁移率变动分析显示，STAT 5在显示JAK 1或JAK 2酪氨酸磷酸化的细胞中被激活。这些结果表明，JAK 1，JAK 2和STAT 5的激活是至关重要的耦合IL-5诱导的酪氨酸磷酸化和最终的有丝分裂，和Pro352和Pro355的脯氨酸丰富的序列似乎在细胞生长中发挥更重要的作用，在JAK 1/STAT 5和JAK 2/STAT 5的激活比Pro353。
The high-affinity receptor (R) for IL-5 consists of a unique alpha chain (IL-5R alpha) and a beta chain (beta c) that is shared with the receptors for IL-3 and granulocyte macrophage colony stimulating factor (GM-CSF). We defined two regions of IL-5R alpha for the IL-5-induced proliferative response, the expression of nuclear proto-oncogenes, and the tyrosine phosphorylation of cellular proteins including beta c, SH2/SH3-containing proteins and JAK2 kinase. In the studies described here, we demonstrate that IL-S, IL-3 or GM-CSF stimulation induces the tyrosine phosphorylation of JAK2, and to a lesser extent JAK1, and of STAT5. Mutational analysis revealed that one of the proline residues, particularly Pro352 and Pro355, in the membrane-proximal proline-rich sequence (Pro352-Pro353-X-Pro355) of the cytoplasmic domain of IL-5R alpha is required for cell proliferation, and for both JAK1 and JAK2 activation. In addition, transfectants expressing chimeric receptors which consist of the extracellular domain of IL-5R alpha and the cytoplasmic domain of beta c responded to IL-5 for proliferation and tyrosine phosphorylation of JAK1. Intriguingly, electrophoretic mobility shift assay analysis revealed that STAT5 was activated in cells showing either JAK1 or JAK2 tyrosine phosphorylation. These results indicate that activation of JAK1, JAK2 and STAT5 is critical to coupling IL-5-induced tyrosine phosphorylation and ultimately mitogenesis, and that Pro352 and Pro355 in the proline-rich sequence appear to play more essential roles in cell growth and in both JAK1/STAT5 and JAK2/STAT5 activation than Pro353 does.