Monocyte 15-lipoxygenase expression is regulated by a novel cytosolic signaling complex with protein kinase C δ and tyrosine-phosphorylated Stat3
Monocyte 15-lipoxygenase expression is regulated by a novel cytosolic signaling complex with protein kinase C δ and tyrosine-phosphorylated Stat3
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DOI：
10.4049/jimmunol.177.6.3771
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发表时间：
2006-09-15
影响因子：
4.4
通讯作者：
Cathcart, Martha K.
中科院分区：
文献类型：
--
作者：
Bhattacharjee, Ashish;Xu, Bo;Cathcart, Martha K.
我们以前的研究表明，IL-13诱导的15-脂氧合酶在原代人单核细胞中的表达受Stat 1和Stat 3的激活以及蛋白激酶C（PKC）δ的调节。IL-13刺激Tyr（705）和Ser（727）上的Stat 3磷酸化。在这项研究中，我们表明，IL-13诱导PKCS与Stat 3，而不是与失速，并需要Stat 3 Ser 727磷酸化的协会。我们发现了一种新的IL-13依赖性PKCS和酪氨酸磷酸化Stat 3的胞浆信号复合物。酪氨酸激酶抑制剂阻断PKC δ与Stat 3的结合以及Stat 3 Ser 727磷酸化。因此，我们假设酪氨酸磷酸化是Stat 3与PKC δ相互作用以及随后Stat 3 Ser的PKC δ-5依赖性磷酸化所必需的（727）。我们开发了一种有效的人单核细胞转染方案。含有Tyr（705）突变的Stat 3的表达抑制PKC 5与Stat 3的结合并阻断Stat 3 Ser 727磷酸化，而野生型Stat 3的转染则没有。此外，通过用含有Tyr（705）或Ser（727）突变的Stat 3或野生型Stat 3转染单核细胞，我们证明Stat 3酪氨酸和丝氨酸磷酸化都是Stat 3与DNA最佳结合和15-脂氧合酶（炎症和凋亡的重要调节因子）最大表达所需的。
Our previous studies demonstrated that the IL-13-induced 15-lipoxygenase expression in primary human monocytes is regulated by the activation of both Stat1 and Stat3 and by protein kinase C (PKC)delta. IL-13 stimulated the phosphorylation of Stat3 on both Tyr(705) and Ser(727). In this study we show that IL-13 induces the association of PKCS with Stat3, not with Stall, and is required for Stat3 Ser 727 phosphorylation. We found a novel IL-13-dependent cytosolic signaling complex of PKCS and tyrosine-phosphorylated Stat3. A tyrosine kinase inhibitor blocked PKC delta association with Stat3 as well as Stat3 Ser 727 phosphorylation. We therefore hypothesized that tyrosine phosphorylation was required for Stat3 interaction with PKC delta and subsequent PKC delta-5-dependent phosphorylation of Stat3 Ser(727). We developed an efficient transfection protocol for human monocytes. Expression of Stat3 containing a mutation in Tyr(705) inhibited the association of PKC5 with Stat3 and blocked Stat3 Ser 727 phosphorylation, whereas transfection with wild-type Stat3 did not. Furthermore, by transfecting monocytes with Stat3 containing mutations in Tyr(705) or Ser(727) or with wild-type Stat3, we demonstrated that both Stat3 tyrosine and serine phosphorylations are required for optimal binding of Stat3 with DNA and maximal expression of 15-lipoxygenase, an important regulator of inflammation and apoptosis.