title: Slit-2/Robo-1 modulates the CXCL12/CXCR4-induced chemotaxis of T cells.
abstract: Slit, which mediates its function by binding to the Roundabout (Robo) receptor, has been shown to regulate neuronal, dendritic, and leukocyte migration. However, the molecular mechanism by which the Slit/Robo complex inhibits the migration of cells is not well defined. Here, we showed that Slit-2 can inhibit the CXCL12-induced chemotaxis and transendothelial migration of T cells and monocytes. We observed that CXCR4 associates with Robo-1 and that Slit-2 treatment enhances this association with the Robo-1 receptor. Robo-1 is a single-pass transmembrane receptor whose intracellular region contains four conserved motifs designated as CC0, CC1, CC2, and CC3. Structural and functional analyses of Robo receptors revealed that interaction of the CC3 motif with the CXCR4 receptor may regulate the CXCL12-induced chemotaxis of T cells. We further characterized Slit-2-mediated inhibition of the CXCL12/CXCR4 chemotactic pathway and found that Slit-2 can block the CXCL12-induced activation of the Src and Lck kinases but not Lyn kinase. Although Slit-2 did not inhibit the CXCL12-induced activation of MAPKs, it did inhibit the Akt phosphorylation and Rac activation induced by this chemokine. Altogether, our studies indicate a novel mechanism by which the Slit/Robo complex may inhibit the CXCR4/CXCL12-mediated chemotaxis of T cells.
authors.affiliation: Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Prasad
authors.forename: Zahida
authors.initials: Z
authors.lastname: Qamri
authors.forename: Jane
authors.initials: J
authors.lastname: Wu
authors.forename: Ramesh K
authors.initials: RK
authors.lastname: Ganju
mesh_terms: D015153:Blotting, Western; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002470:Cell Survival; D002478:Cells, Cultured; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D047468:Immunoprecipitation; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D019169:Jurkat Cells / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009000:Monocytes / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D019718:Receptors, CXCR4 / Q000378:metabolism*; D011971:Receptors, Immunologic; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000502:physiology*; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D000097905:Roundabout Proteins; D000098552:Slit Homolog 2 Protein
chemical_list: D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D036341:Intercellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D009419:Nerve Tissue Proteins; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D019718:Receptors, CXCR4; D011971:Receptors, Immunologic; D020764:cdc42 GTP-Binding Protein; D000097905:Roundabout Proteins; D000098552:Slit Homolog 2 Protein; C515255:CXCL12 protein, human