Exchange of extracellular domains of CCR1 and CCR5 reveals confined functions in CCL5-mediated cell recruitment
Exchange of extracellular domains of CCR1 and CCR5 reveals confined functions in CCL5-mediated cell recruitment
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DOI：
10.1160/th13-05-0420
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发表时间：
2013-08
影响因子：
6.7
通讯作者：
B. Kramp;R. Megens;A. Sarabi;S. Winkler;Delia Projahn;C. Weber;R. Koenen;P. von Hundelshausen
中科院分区：
文献类型：
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作者：
B. Kramp;R. Megens;A. Sarabi;S. Winkler;Delia Projahn;C. Weber;R. Koenen;P. von Hundelshausen
摘要趋化因子CCL5主要通过触发CCR1介导的内皮细胞停滞来将单核细胞招募到炎症组织中，而随后的扩散则由CCR5主导。用CXCl4形成异构体可以增强CCL5诱导的停滞。为了确定受体特异性功能的机制，我们使用了CCL5突变体和转染体，表达携带转座的胞外区的受体嵌合体。CCL5的基本50S簇突变是CCL5表面呈现的一个协调位点，减少了CCR5-但不是CCR1介导的停滞和转运。通过将CCR5-N末端交换为CCR1的N-末端来恢复受损的停滞，CCR1即使在没有50S簇的情况下也支持停滞，而与CCL5蛋白多糖结合所必需的基本40S簇突变无法挽救。CXCL4对CCL5诱导的细胞停滞的增强作用是由CCR1介导的，CCR1需要其细胞外第三环。结构域交换不影响受体二聚体的形成和共定位，表明在停滞微环境中，第三胞外环对异源低聚物具有传感作用。我们的数据确定了CCR1的有限靶向区域，该区域专门用于促进CCL5诱导的停滞和增强对CXCL4-CCL5异构体的响应。注：本稿的审稿过程完全由主编G.Y.H.Lip负责。
Summary The chemokine CCL5 recruits monocytes into inflamed tissues by triggering primarily CCR1-mediated arrest on endothelial cells, whereas subsequent spreading is dominated by CCR5. The CCL5-induced arrest can be enhanced by heteromer formation with CXCL4. To identify mechanisms for receptor-specific functions, we employed CCL5 mutants and transfectants expressing receptor chimeras carrying transposed extracellular regions. Mutation of the basic 50s cluster of CCL5, a coordinative site for CCL5 surface presentation, reduced CCR5- but not CCR1-mediated arrest and transmigration. Impaired arrest was restored by exchanging the CCR5-N-terminus for that of CCR1, which supported arrest even without the 50s cluster, whereas mutation of the basic 40s cluster essential for proteoglycan binding of CCL5 could not be rescued. The enhancement of CCL5-induced arrest by CXCL4 was mediated by CCR1 requiring its third extracellular loop. The domain exchanges did not affect formation and co-localisation of receptor dimers, indicating a sensing role of the third extracellular loop for hetero-oligomers in an arrest microenvironment. Our data identify confined targetable regions of CCR1 specialised to facilitate CCL5-induced arrest and enhanced responsiveness to the CXCL4-CCL5 heteromer. Note: The review process for this manuscript was fully handled by G. Y. H. Lip, Editor in Chief.