The adaptor molecule Nck localizes the WAVE complex to promote actin polymerization during CEACAM3-mediated phagocytosis of bacteria.
The adaptor molecule Nck localizes the WAVE complex to promote actin polymerization during CEACAM3-mediated phagocytosis of bacteria.
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DOI：
10.1371/journal.pone.0032808
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Hauck CR
中科院分区：
文献类型：
--
作者：
Pils S;Kopp K;Peterson L;Delgado Tascón J;Nyffenegger-Jann NJ;Hauck CR
CEACAM 3是一种粒细胞受体，介导人限制性CEACAM结合细菌的调理素非依赖性识别和吞噬作用。CEACAM 3功能依赖于细胞内免疫受体酪氨酸激活基序（ITAM）样序列，该序列在受体接合时被Src家族激酶酪氨酸磷酸化。磷酸化的ITAM样序列通过直接与鸟嘌呤核苷酸交换因子（GEF）Vav相关联来触发Rac的GTP加载。反过来，Rac刺激对肌动蛋白细胞骨架重排至关重要，肌动蛋白细胞骨架重排产生板状突起并导致细菌摄取。在我们目前的研究中，我们提供了生物化学和显微镜证据，衔接蛋白Nck 1和Nck 2，但不是CrkL，Grb 2或SLP-76，结合酪氨酸磷酸化的CEACAM 3。该协会是磷酸化依赖性的，需要Nck SH 2结构域。分离的Nck 1 SH 2结构域的过表达、RNAi介导的Nck 1敲低或Nck 1和Nck 2的遗传缺失干扰CEACAM 3介导的细菌内化和板状伪足突起的形成。Nck与WAVE 2组成型相关，并将肌动蛋白成核促进WAVE复合物导向酪氨酸磷酸化的CEACAM 3。反过来，显性负性WAVE 2以及shRNA介导的WAVE 2或WAVE复合物组分Nap 1的敲低降低了细菌的内化。我们的研究结果提供了新的机制CEACAM 3启动的吞噬作用的见解。我们建议CEACAM 3 ITAM样序列进行优化，以协调有效触发基于肌动蛋白的板状伪足突起和快速病原体吞噬所需的最小细胞因子集。
CEACAM3 is a granulocyte receptor mediating the opsonin-independent recognition and phagocytosis of human-restricted CEACAM-binding bacteria. CEACAM3 function depends on an intracellular immunoreceptor tyrosine-based activation motif (ITAM)-like sequence that is tyrosine phosphorylated by Src family kinases upon receptor engagement. The phosphorylated ITAM-like sequence triggers GTP-loading of Rac by directly associating with the guanine nucleotide exchange factor (GEF) Vav. Rac stimulation in turn is critical for actin cytoskeleton rearrangements that generate lamellipodial protrusions and lead to bacterial uptake. In our present study we provide biochemical and microscopic evidence that the adaptor proteins Nck1 and Nck2, but not CrkL, Grb2 or SLP-76, bind to tyrosine phosphorylated CEACAM3. The association is phosphorylation-dependent and requires the Nck SH2 domain. Overexpression of the isolated Nck1 SH2 domain, RNAi-mediated knock-down of Nck1, or genetic deletion of Nck1 and Nck2 interfere with CEACAM3-mediated bacterial internalization and with the formation of lamellipodial protrusions. Nck is constitutively associated with WAVE2 and directs the actin nucleation promoting WAVE complex to tyrosine phosphorylated CEACAM3. In turn, dominant-negative WAVE2 as well as shRNA-mediated knock-down of WAVE2 or the WAVE-complex component Nap1 reduce internalization of bacteria. Our results provide novel mechanistic insight into CEACAM3-initiated phagocytosis. We suggest that the CEACAM3 ITAM-like sequence is optimized to co-ordinate a minimal set of cellular factors needed to efficiently trigger actin-based lamellipodial protrusions and rapid pathogen engulfment.
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影响因子：
16
作者：
Lebensohn AM;Kirschner MW
通讯作者：
Kirschner MW
影响因子：
6.6
作者：
Hauck, CR;Agerer, F;Schmitter, T
通讯作者：
Schmitter, T
DOI：
10.1126/stke.3772007re2
发表时间：
2007-03-13
期刊：
Science's STKE : signal transduction knowledge environment
影响因子：
--
作者：
Abram, Clare L;Lowell, Clifford A
通讯作者：
Lowell, Clifford A
DOI：
10.1084/jem.186.7.1027
发表时间：
1997-10-06
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Crowley MT;Costello PS;Fitzer-Attas CJ;Turner M;Meng F;Lowell C;Tybulewicz VL;DeFranco AL
通讯作者：
DeFranco AL
影响因子：
30.5
作者：
Boulton, IC;Gray-Owen, SD
通讯作者：
Gray-Owen, SD