Rab11-family interacting protein 2 and myosin Vb are required for CXCR2 recycling and receptor-mediated chemotaxis
Rab11-family interacting protein 2 and myosin Vb are required for CXCR2 recycling and receptor-mediated chemotaxis
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DOI：
10.1091/mbc.e03-09-0706
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发表时间：
2004-05-01
影响因子：
3.3
通讯作者：
Richmond, A
中科院分区：
文献类型：
--
作者：
Fan, GH;Lapierre, LA;Richmond, A
激动剂刺激的内化，然后再循环到细胞膜，在微调趋化因子受体的活性方面发挥着重要作用。由于趋化因子受体的循环对于重建细胞对配体的反应性是至关重要的，因此了解受体循环和再增敏的机制是至关重要的。在本研究中，我们证明了趋化因子受体CXCR2与肌球蛋白VB和Rab11家族相互作用蛋白2(FIP2)以配体依赖的方式相互作用。受体C-末端结构域的截断不影响这种联系，表明相互作用发生在CXCR2的C末端上游。配体刺激后，内化的CXCR2与肌球蛋白VB和Rab11-FIP2共定位于Rab11a阳性小泡中。共定位持续时间接近2小时，在配体刺激4小时后观察到很少的共定位。CXCR2还分别与肌球蛋白VB和Rab11-FIP2的N端截短突变体Rab11-FIP2(129-512)或Myosin VB Tail或Rab11-FIP2(129-512)共定位，但以高度浓缩的方式存在。增强的绿色荧光蛋白标记的肌球蛋白VB Tail的表达显著抑制了CXCR2的再循环和再增敏。表达Rab11-FIP2(129-512)也减少了CXCR2的循环。此外，Myosin VB Tail的表达降低了CXCR2和CXCR4介导的趋化作用。这些数据表明，Rab11-FIP2和肌球蛋白VB调节CXCR2的循环和受体介导的趋化作用，内化的CXCR2通过Rab11a阳性的循环系统是对趋化因子的生理反应的关键。
Agonist-stimulated internalization followed by recycling to the cell membrane play an important role in fine-tuning the activity of chemokine receptors. Because the recycling of chemokine receptors is critical for the reestablishment of the cellular responsiveness to ligand, it is crucial to understand the mechanisms underlying the receptor recycling and resensitization. In the present study, we have demonstrated that the chemokine receptor CXCR2 associated with myosin Vb and Rab11-family interacting protein 2 (FIP2) in a ligand-dependent manner. Truncation of the C-terminal domain of the receptor did not affect the association, suggesting that the interactions occur upstream of the C terminus of CXCR2. After ligand stimulation, the internalized CXCR2 colocalized with myosin Vb and Rab11-FIP2 in Rab11a-positive vesicles. The colocalization lasted for similar to2 h, and little colocalization was observed after 4 h of ligand stimulation. CXCR2 also colocalized with myosin Vb tail or Rab11-FIP2 (129-512), the N-terminal-truncated mutants of myosin Vb and Rab11-FIP2, respectively, but in a highly condensed manner. Expression of the enhanced green fluorescent protein-tagged myosin Vb tail significantly retarded the recycling and resensitization of CXCR2. CXCR2 recycling was also reduced by the expression Rab11-FIP2 (129-512). Moreover, expression of the myosin Vb tail reduced CXCR2- and CXCR4-mediated chemotaxis. These data indicate that Rab11-FIP2 and myosin Vb regulate CXCR2 recycling and receptor-mediated chemotaxis and that passage of internalized CXCR2 through Rab11a-positive recycling system is critical for physiological response to a chemokine.