The Kinase Activity of Rip2 Determines Its Stability and Consequently Nod1-and Nod2-mediated Immune Responses
The Kinase Activity of Rip2 Determines Its Stability and Consequently Nod1-and Nod2-mediated Immune Responses
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DOI：
10.1074/jbc.m109.006353
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发表时间：
2009-07-17
影响因子：
4.8
通讯作者：
Marsland, Benjamin J.
中科院分区：
文献类型：
--
作者：
Nembrini, Chiara;Kisielow, Jan;Marsland, Benjamin J.
Rip 2（RICK，CARD 3）已被鉴定为模式识别受体Nod 1和Nod 2下游的关键效应分子;然而，其作用机制仍有待阐明。特别是，目前还不清楚它的激酶活性是否是信号传导或维持蛋白质稳定性所必需的。我们研究了不同逆转录病毒表达的激酶死亡Rip 2突变体的表达水平和Rip 2激酶活性在Nod 1和Nod 2刺激后的信号传导事件中的作用。我们发现，在原代细胞表达激酶失活Rip 2，蛋白质水平严重受损，稳定性不能重建的磷酸化模拟突变在其自身磷酸化位点。因此，响应于Nod 1和Nod 2配体的炎性细胞因子产生在Rip 2激酶活性的情况下在体外和体内都被废除。我们的研究结果突出了Rip 2激酶活性在赋予蛋白质稳定性方面发挥的核心作用，从而在Nod 1和Nod 2介导的先天免疫应答的保存中发挥作用。
Rip2 (RICK, CARD3) has been identified as a key effector molecule downstream of the pattern recognition receptors, Nod1 and Nod2; however, its mechanism of action remains to be elucidated. In particular, it is unclear whether its kinase activity is required for signaling or for maintaining protein stability. We have investigated the expression level of different retrovirally expressed kinase-dead Rip2 mutants and the role of Rip2 kinase activity in the signaling events that follow Nod1 and Nod2 stimulation. We show that in primary cells expressing kinase-inactive Rip2, protein levels were severely compromised, and stability could not be reconstituted by the addition of a phospho-mimetic mutation in its autophosphorylation site. Consequently, inflammatory cytokine production in response to Nod1 and Nod2 ligands was abrogated both in vitro and in vivo in the absence of Rip2 kinase activity. Our results highlight the central role that Rip2 kinase activity plays in conferring stability to the protein and thus in the preservation of Nod1- and Nod2-mediated innate immune responses.