Fine Specificity and Molecular Competition in SLAM Family Receptor Signalling
Fine Specificity and Molecular Competition in SLAM Family Receptor Signalling
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SLAM 家族受体信号传导的精细特异性和分子竞争
作者：
T. Wilson;Lee Garner;C. Metcalfe;Elliott King;S. Margraf;Marion H. Brown
SLAM家族受体通过将含有激活性和抑制性SH 2结构域的蛋白质募集到基于免疫受体酪氨酸的开关基序（ITSM）来调节免疫中的激活和抑制。衔接子SAP和EAT-2与SLAM家族受体的细胞质区域中的ITSM的结合对于活化是重要的。我们分析了SLAM家族受体磷酸化ITSM和EAT-2中保守的酪氨酸基序对含SH 2结构域的信号蛋白的精细特异性。与描述CRACC（SLAMF 7）对EAT-2的依赖性的文献一致，CRACC结合EAT-2（KD = 0.003 μM）的亲和力比SAP（KD = 0.44 μM）高约2个数量级。 在NK 92细胞中的细胞毒性测定中的RNA干扰显示CRACC除了EAT-2之外还依赖于SAP，这表明SAP和EAT-2的选择性可能取决于两种衔接子的相对浓度。SAP在NK 92细胞中的浓度是EAT-2的4倍。与SAP相比，EAT-2募集及其下游效应物的意义还没有得到很好的表征。我们确定PLCγ1和PLCγ2是EAT-2尾部的主要结合伴侣。PLCγ1和PLCγ2通过CD 244（SLAMF 4）、NTB-A（SLAMF 6）和CRACC对NK 92细胞的细胞毒性具有重要功能。比较激活和抑制信号传导介质的SH 2结构域的特异性，揭示了CD 244（SLAMF 4）ITSM的亲和力层次。虽然与SAP或EAT-2相比，磷酸酶SH 2结构域与CD 244的单个ITSM的结合较弱，但SHP-2的串联SH 2结构域与人CD 244中含有串联磷酸化ITSM的较长肽的结合使亲和力增加10倍。酪氨酸磷酸酶SHP-2的浓度比衔接子SAP和EAT-2高一个数量级。这些数据证明了一种机制，直接招聘的磷酸酶抑制信号的ITSM，同时解释竞争优势的SAP和EAT-2。
SLAM family receptors regulate activation and inhibition in immunity through recruitment of activating and inhibitory SH2 domain containing proteins to immunoreceptor tyrosine based switch motifs (ITSMs). Binding of the adaptors, SAP and EAT-2 to ITSMs in the cytoplasmic regions of SLAM family receptors is important for activation. We analysed the fine specificity of SLAM family receptor phosphorylated ITSMs and the conserved tyrosine motif in EAT-2 for SH2 domain containing signalling proteins. Consistent with the literature describing dependence of CRACC (SLAMF7) on EAT-2, CRACC bound EAT-2 (KD = 0.003 μM) with approximately 2 orders of magnitude greater affinity than SAP (KD = 0.44 μM). RNA interference in cytotoxicity assays in NK92 cells showed dependence of CRACC on SAP in addition to EAT-2, indicating selectivity of SAP and EAT-2 may depend on the relative concentrations of the two adaptors. The concentration of SAP was four fold higher than EAT-2 in NK92 cells. Compared with SAP, the significance of EAT-2 recruitment and its downstream effectors are not well characterised. We identified PLCγ1 and PLCγ2 as principal binding partners for the EAT-2 tail. Both PLCγ1 and PLCγ2 are functionally important for cytotoxicity in NK92 cells through CD244 (SLAMF4), NTB-A (SLAMF6) and CRACC. Comparison of the specificity of SH2 domains from activating and inhibitory signalling mediators revealed a hierarchy of affinities for CD244 (SLAMF4) ITSMs. While binding of phosphatase SH2 domains to individual ITSMs of CD244 was weak compared with SAP or EAT-2, binding of tandem SH2 domains of SHP-2 to longer peptides containing tandem phosphorylated ITSMs in human CD244 increased the affinity ten fold. The concentration of the tyrosine phosphatase, SHP-2 was in the order of a magnitude higher than the adaptors, SAP and EAT-2. These data demonstrate a mechanism for direct recruitment of phosphatases in inhibitory signalling by ITSMs, while explaining competitive dominance of SAP and EAT-2.
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影响因子：
4.3
作者：
Argov,S;Johnson,DR;Collins,M;Koren,HS;Lipscomb,H;Purtilo,DT
通讯作者：
Purtilo,DT
DOI：
10.1073/pnas.94.7.2999
发表时间：
1997-04-01
影响因子：
11.1
作者：
Ji, QS;Winnier, GE;Carpenter, G
通讯作者：
Carpenter, G
影响因子：
20.3
作者：
J. Sayós;M. Martín;A. Chen;M. Simarro;D. Howie;M. Morra;P. Engel;C. Terhorst
通讯作者：
J. Sayós;M. Martín;A. Chen;M. Simarro;D. Howie;M. Morra;P. Engel;C. Terhorst
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DOI：
--
发表时间：
1989
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
--
作者：
Shimizu,Y;DeMars,R
通讯作者：
DeMars,R
影响因子：
20.3
作者：
Eissmann, P;Beauchamp, L;Watzl, C
通讯作者：
Watzl, C