Ceramide directly activates protein kinase C ζ to regulate a stress-activated protein kinase signaling complex
Ceramide directly activates protein kinase C ζ to regulate a stress-activated protein kinase signaling complex
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DOI：
10.1074/jbc.m007346200
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发表时间：
2000-11-10
影响因子：
4.8
通讯作者：
Kester, M
中科院分区：
文献类型：
--
作者：
Bourbon, NA;Yun, J;Kester, M
我们之前已经证明，白介素1 （IL-1）受体生成的神经酰胺通过激活应激激活蛋白激酶（SAPK）级联中的上游激酶，诱导平滑肌周细胞的生长停滞。我们现在报道了神经酰胺激活人胚胎肾细胞（HEK-293）中SAPK信号通路的机制。我们证明了神经酰胺活化蛋白激酶C zeta （PKC zeta）介导SAPK信号复合物的形成和随后的生长抑制。神经酰胺直接激活体外免疫沉淀和重组人PKC zeta。此外，神经酰胺可以激活SAPK活性，而这种活性被PKC zeta的显性阴性突变体阻断。共免疫沉淀研究表明，神经酰胺诱导SAPK与PKC zeta结合，而不与PKC epsilon结合。此外，神经酰胺处理诱导PKC zeta与磷酸化的SEK和MEKK1 （SAPK信号复合物的元件）结合。神经酰胺诱导细胞周期阻滞的生物学作用是通过组成活性PKC zeta的过度表达来模拟的。总之，这些研究表明，神经酰胺通过增强PKC zeta与MEKK1、SEK和SAPK形成信号复合物的能力来诱导细胞周期阻滞。
We have previously shown that interleukin 1 (IL-1)receptor-generated ceramide induces growth arrest in smooth muscle pericytes by activating an upstream kinase in the stress-activated protein kinase (SAPK) cascade. We now report the mechanism by which ceramide activates the SAPK signaling pathway in human embryonic kidney cells (HEK-293). We demonstrate that ceramide activation of protein kinase C zeta (PKC zeta) mediates SAPK signal complex formation and subsequent growth suppression. Ceramide directly activates both immunoprecipitated and recombinant human PKC zeta in vitro. Additionally, ceramide activates SAPK activity, which is blocked with a dominant-negative mutant of PKC zeta Coimmunoprecipitation studies reveal that ceramide induces the association of SAPK with PKC zeta, but not with PKC epsilon. In addition, ceramide treatment induces PKC zeta association with phosphorylated SEK and MEKK1, elements of the SAPK signaling complex. The biological role of ceramide to induce cell cycle arrest is mimicked by overexpression of a constitutively active PKC zeta. Together, these studies demonstrate that ceramide induces cell cycle arrest by enhancing the ability of PKC zeta to form a signaling complex with MEKK1, SEK, and SAPK.