title: Interaction of CD154 with different receptors and its role in bidirectional signals.
abstract: In addition to its classical receptor, CD40, it is now well established that CD154 also binds αIIbβ3, α5β1, and αMβ2 integrins. Although these integrins are all members of the same family, they bind CD154 differently. The current investigation aims to analyze the interaction of CD154 with α5β1 and αMβ2 and investigate its role in bidirectional signals in various human cell lines. Results obtained herein indicate that the CD154 residues involved in the interaction with α5β1 are N151 and Q166, whereas those involved in αMβ2 binding are common to residues required for CD40, namely Y145 and R203. Soluble CD40/CD154 or αMβ2/CD154 complexes do not interfere with the binding of CD154 to α5β1-positive cells, but inhibit the binding of CD154 to CD40- or αMβ2-positive cells, respectively. Ligation of CD154 on CD154-positive cells with soluble CD40, αIIbβ3, α5β1, or αMβ2 stimulates intracellular signaling, including MAPK phosphorylation. Given that CD154 exists as a trimer, our data strongly suggest that CD154 may bind concomitantly to two receptors of the same or different family, and biologically activate cells expressing both receptors. The characterization of CD154/receptor interactions helps the identification of new therapeutic targets for the prevention and/or treatment of CD154-associated autoimmune and inflammatory diseases.
authors.affiliation: Laboratoire d'immunologie cellulaire et moléculaire, Centre de Recherche-Centre Hospitalier de l'Université de Montréal (CR-CHUM), Montréal, Canada.
authors.forename: Haydar
authors.initials: H
authors.lastname: Alturaihi
authors.forename: Ghada S
authors.initials: GS
authors.lastname: Hassan
authors.forename: Loubna
authors.initials: L
authors.lastname: Al-Zoobi
authors.forename: Suzanne
authors.initials: S
authors.lastname: Salti
authors.forename: Youssef
authors.initials: Y
authors.lastname: Darif
authors.forename: Daniel
authors.initials: D
authors.lastname: Yacoub
authors.forename: Souhad
authors.initials: S
authors.lastname: El Akoum
authors.forename: Mounia
authors.initials: M
authors.lastname: Oudghiri
authors.forename: Yahye
authors.initials: Y
authors.lastname: Merhi
authors.forename: Walid
authors.initials: W
authors.lastname: Mourad
mesh_terms: D000818:Animals; D019013:CD40 Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D023201:CD40 Ligand / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D045744:Cell Line, Tumor; D004331:Drosophila melanogaster; D015870:Gene Expression; D006801:Humans; D039081:Integrin alpha5beta1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016177:Macrophage-1 Antigen / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D019013:CD40 Antigens; D039081:Integrin alpha5beta1; D016177:Macrophage-1 Antigen; D011994:Recombinant Proteins; D023201:CD40 Ligand; D020928:Mitogen-Activated Protein Kinases
keywords: Activation; Binding; CD154; CD40; Integrins