RT info:eu-repo/semantics/article T1 CD229 (Ly9) lymphocyte cell surface receptor Interacts homophilically through Its N-Terminal domain and relocalizes to the immunological synapse A1 Romero, Xavier A1 Zapater, Nuria A1 Calvo, María A1 Kalko, Susana G. A1 Fuente García, Miguel Ángel de la A1 Tovar, Victoria A1 Ockeloen, Charlotte A1 Pizcueta, Pilar A1 Engel, Pablo K1 Inmunología AB CD229 is a member of the CD150 family of the Ig superfamily expressed on T and B cells. Receptors of this family regulatecytokine production and cytotoxicity of lymphocytes and NK cells. The cytoplasmic tail of CD229 binds to SAP, a protein that isdefective in X-linked lymphoproliferative syndrome. To identify the CD229 ligand, we generated a soluble Ig fusion proteincontaining the two N-terminal extracellular domains of human CD229 (CD229-Ig). CD229-Ig bound to CD229-transfected cells,whereas no binding was detected on cells expressing other CD150 family receptors, showing that CD229 binds homophilically.Both human and mouse CD229 interacted with itself. Domain deletion mutants showed that the N-terminal Ig-domain mediateshomophilic adhesion. CD229-CD229 binding was severely compromised when the charged amino acids E27 and E29 on thepredicted B-C loop and R89 on the F-G loop of the N-terminal domain were mutated to alanine. In contrast, one mutation, R44A,enhanced the homophilic interaction. Confocal microscopy image analysis revealed relocalization of CD229 to the contact area ofT and B cells during Ag-dependent immune synapse formation. Thus, CD229 is its own ligand and participates in the immunologicalsynapse. PB American Association of Immunologists SN 0022-1767 YR 2005 FD 2005 LK http://uvadoc.uva.es/handle/10324/10117 UL http://uvadoc.uva.es/handle/10324/10117 LA eng NO The Journal of Immunology, 2005, vol. 174, n. 11. p. 7033–7042. NO Producción Científica DS UVaDOC RD 27-abr-2024