Chemokine receptors CXCR7 and CXCR4 bind to the same ligand stromal cell derived factor-1alpha (SDF-1α/CXCL12). We assessed the downstream signaling pathways mediated by CXCL12-CXCR7 interaction in Jurkat T cells. All experiments were carried out after functionally blocking the CXCR4 receptor. CXCL12, on binding CXCR7, induced phosphorylation of extra cellular regulated protein kinases (ERK 1/2) and Akt. Selective inhibition of each signal demonstrated that phosphorylated ERK 1/2 is essential for chemotaxis and survival of T cells whereas activation of Akt promotes only cell survival. Another interesting finding of this study is that CXCL12-CXCR7 interaction under normal physiological conditions does not activate the p38 pathway. Furthermore, we observed that the CXCL12 signaling via CXCR7 is Giα independent. Our findings suggest that CXCR7 promotes cell survival and does not induce cell death in T cells. The CXCL12 signaling via CXCR7 may be crucial in determining the fate of the activated T cells.

中文翻译：

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CXCR7介导的ERK的Giα独立活化和Akt促进T细胞的细胞存活和趋化性。

趋化因子受体CXCR7和CXCR4与同一配体基质细胞衍生因子-1alpha（SDF-1α/ CXCL12）结合。我们评估了Jurkat T细胞中CXCL12-CXCR7相互作用介导的下游信号通路。所有实验均在功能上阻断CXCR4受体后进行。CXCL12与CXCR7结合后，诱导了细胞外调节蛋白激酶（ERK 1/2）和Akt的磷酸化。对每种信号的选择性抑制表明磷酸化的ERK 1/2对T细胞的趋化性和存活至关重要，而Akt的激活仅促进细胞存活。这项研究的另一个有趣发现是，在正常生理条件下，CXCL12-CXCR7相互作用不会激活p38途径。此外，我们观察到通过CXCR7传递的CXCL12信号是Giα独立的。我们的发现表明CXCR7可以促进细胞存活，并且不会诱导T细胞中的细胞死亡。通过CXCR7发出的CXCL12信号对于确定激活的T细胞的命运可能至关重要。