title: Caveolin-1 triggers T-cell activation via CD26 in association with CARMA1.
abstract: CD26 is a widely distributed 110-kDa cell surface glycoprotein with an important role in T-cell costimulation. We demonstrated previously that CD26 binds to caveolin-1 in antigen-presenting cells, and following exogenous CD26 stimulation, Tollip and IRAK-1 disengage from caveolin-1 in antigen-presenting cells. IRAK-1 is then subsequently phosphorylated to up-regulate CD86 expression, resulting in subsequent T-cell proliferation. However, it is unclear whether caveolin-1 is a costimulatory ligand for CD26 in T-cells. Using soluble caveolin-1-Fc fusion protein, we now show that caveolin-1 is the costimulatory ligand for CD26, and that ligation of CD26 by caveolin-1 induces T-cell proliferation and NF-kappaB activation in a T-cell receptor/CD3-dependent manner. We also demonstrated that the cytoplasmic tail of CD26 interacts with CARMA1 in T-cells, resulting in signaling events that lead to NF-kappaB activation. Ligation of CD26 by caveolin-1 recruits a complex consisting of CD26, CARMA1, Bcl10, and IkappaB kinase to lipid rafts. Taken together, our findings provide novel insights into the regulation of T-cell costimulation via the CD26 molecule.
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ohnuma
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Uchiyama
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Tadanori
authors.initials: T
authors.lastname: Yamochi
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Kunika
authors.initials: K
authors.lastname: Nishibashi
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Hosono
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kina
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Molecular and Cellular Oncology, University of Texas, M. D. Anderson Cancer Center, Houston, Texas 77030.
authors.forename: Xin
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Hematologic Malignancies, Nevada Cancer Institute, Las Vegas, Nevada 89135.
authors.forename: Nam H
authors.initials: NH
authors.lastname: Dang
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan. Electronic address: morimoto@ims.u-tokyo.ac.jp.
authors.forename: Chikao
authors.initials: C
authors.lastname: Morimoto
mesh_terms: D000243:Adenosine Deaminase / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000502:physiology*; D053468:CARD Signaling Adaptor Proteins / Q000502:physiology*; D051242:Caveolin 1 / Q000502:physiology*; D018819:Dipeptidyl Peptidase 4 / Q000502:physiology*; D006023:Glycoproteins / Q000502:physiology*; D006162:Guanylate Cyclase / Q000502:physiology*; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000276:immunology*; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D053468:CARD Signaling Adaptor Proteins; C495540:CAV1 protein, human; D051242:Caveolin 1; D006023:Glycoproteins; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4; D000243:Adenosine Deaminase; C426242:CARD11 protein, human; D006162:Guanylate Cyclase