title: Differential function of Themis CABIT domains during T cell development.
abstract: Themis (also named Gasp) is a newly identified Grb2-binding protein that is essential for thymocyte positive selection. Despite the possible involvement of Themis in TCR-mediated signal transduction, its function remains unresolved and controversial. Themis contains two functionally uncharacterized regions called CABIT (cysteine-containing, all-β in Themis) domains, a nuclear localization signal (NLS), and a proline-rich sequence (PRS). To elucidate the role of these motifs in Themis's function in vivo, we established a series of mutant Themis transgenic mice on a Themis(-/-) background. Deletion of the highly conserved Core motif of CABIT1 or CABIT2 (Core1 or Core2, respectively), the NLS, or the PRS abolished Grb2-association, as well as TCR-dependent tyrosine-phosphorylation and the ability to induce positive selection in the thymus. The NLS and Core1 motifs were required for the nuclear localization of Themis, whereas Core2 and PRS were not. Furthermore, expression of ΔCore1- but not ΔCore2-Themis conferred dominant negative-type inhibition on T cell development. Collectively, our current results indicate that PRS, NLS, CABIT1, and CABIT2 are all required for positive selection, and that each of the CABIT domains exerts distinct functions during positive selection.
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nitta
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kaji
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Takashima
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Oda
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Norimasa
authors.initials: N
authors.lastname: Tamehiro
authors.affiliation: Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Motohito
authors.initials: M
authors.lastname: Goto
authors.affiliation: Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan ; Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Okamura
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Patrick
authors.affiliation: Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D008822:Mice, Transgenic; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D060168:Thymocytes / Q000166:cytology* / Q000378:metabolism
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; C544192:themis protein, mouse