[Isoform 1]: Receptor for the C-X-C chemokines CXCL9, CXCL10 and CXCL11, and mediates the proliferation, survival and angiogenic activity of human mesangial cells (HMC) through a heterotrimeric G- protein signaling pathway (PubMed:12782716). Probably promotes cell chemotaxis response. Upon activation by PF4, induces activated T- lymphocyte migration mediated via downstream Ras/extracellular signal- regulated kinase (ERK) signaling. {ECO:0000269|PubMed:12782716, ECO:0000269|PubMed:18174362, ECO:0000269|PubMed:24469069}. [Isoform 2]: Receptor for the C-X-C chemokine CXCL4 and also mediates the inhibitory activities of CXCL9, CXCL10 and CXCL11 on the proliferation, survival and angiogenic activity of human microvascular endothelial cells (HMVEC) through a cAMP-mediated signaling pathway (PubMed:12782716). Does not promote cell chemotaxis response. Interaction with CXCL4 or CXCL10 leads to activation of the p38MAPK pathway and contributes to inhibition of angiogenesis. Overexpression in renal cancer cells down-regulates expression of the anti-apoptotic protein HMOX1 and promotes apoptosis. . [Isoform 3]: Mediates the activity of CXCL11. This is the function of ENSG00000186810 (CXCR3, C-X-C motif chemokine receptor 3).