The Cbl-b RING finger domain has a limited role in regulating inflammatory cytokine production by IgE-activated mast cells
The Cbl-b RING finger domain has a limited role in regulating inflammatory cytokine production by IgE-activated mast cells
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DOI：
10.1016/j.molimm.2007.08.002
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发表时间：
2008-02-01
影响因子：
3.6
通讯作者：
Langdon, Wallace Y.
中科院分区：
文献类型：
--
作者：
Oksvold, Morten P.;Dagger, Samantha A.;Langdon, Wallace Y.
环指型E3泛素连接酶，Cbl-b，在骨髓来源的肥大细胞（BMMC）中大量表达，并作为高亲和力IgE受体（Fc β RI）信号应答的有效负调节剂发挥作用。为了确定Cbl-b E3连接酶活性的贡献，我们产生了在RING指结构域中具有功能缺失突变的敲入小鼠。我们发现这些小鼠是健康的，并且与同等的c-Cbl RING指突变小鼠不同，它们以预期的频率产生纯合子后代。对来自Cbl-b敲除和Cbl-b RING指突变小鼠的BMMC的比较分析显示，对于大多数检查的参数，与野生型细胞相比，两者均显示出类似的增强的Fc γ RI信号传导。一个值得注意的例外是，与RING指突变体衍生的细胞相比，Cbl-B敲除BMMC中I κ B激酶（1 KK）的活化水平明显更高。此外，来自Cbl-b RING指突变体的BMMC并不延迟Fc ε RI内化至对于敲除细胞所观察到的程度。然而，最引人注目的是发现RING指突变型肥大细胞在Fc β RI活化后不产生非常高水平的TNF-α、IL-6和MCP-1，这在Cbl-b敲除培养物中是明显的。因此，Cbl-b作为促进炎性细胞因子产生的Fc β RI信号传导的负调节剂发挥作用的能力在很大程度上不依赖于RING指结构域。(c)2007爱思唯尔有限公司保留所有权利。
The RING finger type E3 ubiquitin ligase, Cbl-b, is abundantly expressed in bone marrow-derived mast cells (BMMCs) and functions as a potent negative regulator of signalling responses from the high-affinity IgE receptor (Fc epsilon RI). To determine the contribution of Cbl-b E3 ligase activity we generated knockin mice with a loss-of-function mutation in the RING finger domain. We find the mice to be healthy and, unlike equivalent c-Cbl RING finger mutant mice, produce homozygous offspring at the expected frequency. Comparative analyses of BMMCs from Cbl-b knockout and Cbl-b RING finger mutant mice revealed that both showed similarly enhanced Fc epsilon RI signalling compared to wild-type cells for most parameters examined. A notable exception was a markedly higher level of activation of I kappa B kinase (1KK) in Cbl-b knockout BMMC compared to RING finger mutant-derived cells. In addition BMMCs from the Cbl-b RING finger mutant did not retard Fc epsilon RI internalization to the extent observed for knockout cells. Most striking however was the finding that RING finger mutant mast cells do not produce the very high levels of TNF-alpha, IL-6, and MCP-1 evident in Cbl-b knockout cultures following Fc epsilon RI activation. Thus the ability of Cbl-b to function as a negative regulator of Fc epsilon RI signalling that promotes inflammatory cytokine production is largely independent of the RING finger domain. (c) 2007 Elsevier Ltd. All rights reserved.