title: Complement regulatory protein Crry/p65-mediated signaling in T lymphocytes: role of its cytoplasmic domain and partitioning into lipid rafts.
abstract: Crry/p65 is a type I glycoprotein, which protects mouse T cells from complement attack. We have previously shown that complement receptor I-related protein Crry/p65 (Crry) ligation has a costimulatory effect on mouse CD4+ T cell activation. Here, we have examined the mechanisms responsible for Crry costimulation, addressing the question of whether Crry potentiates signal transduction starting at the T cell receptor (TCR)/CD3 complex or promotes distinct costimulatory signals. We show that Crry increases early TCR-dependent activation signals, including p56lck-, zeta-associated protein-70 (ZAP-70), Vav-1, Akt, and extracellular signal-regulated kinase (ERK) phosphorylation but also costimulation-dependent mitogen-activated protein kinases (MAPK), such as the stress-activated c-Jun N-terminal kinase (JNK). It is intriguing that Crry costimulus enhanced p38 MAPK activation in T helper cell type 1 (Th1) but not in Th2 cells. A fraction of Crry is found consistently in the detergent-insoluble membrane fraction of Th1 or Th2 cells or CD4+ lymphoblasts. Crry costimulation induced clustering of lipid rafts, increasing their content in Crry, CD3epsilon, and p59-60 forms of p56lck, and caused actin polymerization close to the site of activation in Th2 cells. Such events were inhibited by wortmannin, suggesting a role for phosphatidylinositol-3 kinase in these effects. The Crry cytoplasmic domain was required for JNK activation and interleukin-4 secretion but not for the presence of Crry in rafts or activation of p56lck, ZAP-70, Akt, Vav-1, or ERK. This suggests that Crry costimulation involves two different but not mutually exclusive signal transduction modules. The dual function of Crry as a complement regulatory protein and as a T cell costimulator illustrates the importance of complement regulatory proteins as links between innate and adaptive immunity.
authors.affiliation: Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo km 2, Majadahonda, 28220-Madrid, Spain.
authors.forename: Arturo
authors.initials: A
authors.lastname: Jiménez-Periañez
authors.forename: Gloria
authors.initials: G
authors.lastname: Ojeda
authors.forename: Gabriel
authors.initials: G
authors.lastname: Criado
authors.forename: Alejandra
authors.initials: A
authors.lastname: Sánchez
authors.forename: Eliana
authors.initials: E
authors.lastname: Pini
authors.forename: Joaquín
authors.initials: J
authors.lastname: Madrenas
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: Rojo
authors.forename: Pilar
authors.initials: P
authors.lastname: Portolés
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000378:metabolism; D002460:Cell Line; D003593:Cytoplasm / Q000276:immunology* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D007113:Immunity, Innate / Q000276:immunology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism; D021962:Membrane Microdomains / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D051058:Oncogene Protein v-akt / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D011951:Receptors, Complement / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D017463:Receptors, Complement 3b; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D018417:Th1 Cells / Q000276:immunology; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D017252:CD3 Complex; C121704:CD3 antigen, zeta chain; C081470:Cr1l protein, mouse; D051567:Proto-Oncogene Proteins c-vav; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; C496619:Vav1 protein, mouse; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051746:ZAP-70 Protein-Tyrosine Kinase; D051058:Oncogene Protein v-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases