tailieunhanh - Báo cáo khoa học: Syndecan-4 is a signaling molecule for stromal cell-derived factor-1 (SDF-1)/ CXCL12

Stromal cell-derived factor-1 (SDF-1)⁄CXCL12, the ligand for CXCR4, induces signal transduction. We previously showed that CXCL12 binds to high- and low-affinity sites expressed by primary cells and cell lines, and forms complexes with CXCR4 as expected and also with a proteoglycan, syndecan-4, but does not form complexes with syndecan-1, syndecan-2, CD44 or beta-glycan. We also demonstrated the occurrence of a CXCL12-independent heteromeric complex between CXCR4 and syndecan-4. | ềFEBS Journal Syndecan-4 is a signaling molecule for stromal cell-derived factor-1 SDF-1 cXcL12 Nathalie Charnaux1 2 Severine Brule1 2 Morgan Hamon1 Thomas Chaigneau1 Line Saffar1 Catherine Prost1 Nicole Lievre1 and Liliane Gattegno1 2 1 Laboratoire de Biologie Cellulaire Biotherapies Benefices et Risques UPRES 3410 Universite Paris XIII Bobigny France 2 HopitalJean Verdier Bondy France Keywords CxCr4 proteoglycan SDF-1 CXCL12 syndecan-4 Correspondence L. Gattegno Laboratoire de Biologie Cellulaire Biotherapies Benefices et Risques UPRES 3410 Universite Paris XIII 74 rue MarcelCachin 93017 Bobigny France HopitalJean Verdier 93017 Bondy France Fax 33 1 48026503 Tel 33 1 48387752 E-mail These authors contributed equally to this work. Received 18 January 2005 accepted 21 February 2005 doi Stromal cell-derived factor-1 SDF-1 CXCL12 the ligand for CXCR4 induces signal transduction. We previously showed that CXCL12 binds to high- and low-affinity sites expressed by primary cells and cell lines and forms complexes with CXCR4 as expected and also with a proteoglycan syndecan-4 but does not form complexes with syndecan-1 syndecan-2 CD44 or beta-glycan. We also demonstrated the occurrence of a CXCL12-independent heteromeric complex between CXCR4 and syndecan-4. However our data ruled out the glycosaminoglycan-dependent binding of CXCL12 to HeLa cells facilitating the binding of this chemokine to CXCR4. Here we demonstrate that CXCL12 directly binds to syndecan-4 in a glycosaminoglycan-dependent manner. We show that upon stimulation of HeLa cells by CXCL12 CXCR4 becomes tyrosine phosphorylated as expected while syndecan-4 but not syndecan-1 syndecan-2 or beta-glycan also undergoes such tyrosine phosphorylation. Moreover tyrosine-phosphorylated syndecan-4 from CXCL12-stimulated HeLa cells physically coassociates with tyrosine phosphorylated CXCR4. Pretreatment of the cells with heparitinases I and III .