title: The CD47-SIRPα signalling system: its physiological roles and therapeutic application.
abstract: Signal regulatory protein α (SIRPα), also known as SHPS-1/BIT/ CD172a, is an immunoglobulin superfamily protein that binds to the protein tyrosine phosphatases SHP-1 and SHP-2 through its cytoplasmic region. CD47, another immunoglobulin superfamily protein, is a ligand for SIRPα, with the two proteins constituting a cell-cell communication system (the CD47-SIRPα signalling system). SIRPα is particularly abundant in the myeloid-lineage hematopoietic cells such as macrophages or dendritic cells (DCs), whereas CD47 is expressed ubiquitously. Interaction of CD47 (on red blood cells) with SIRPα (on macrophages) is thought to prevent the phagocytosis by the latter cells of the former cells, determining the lifespan of red blood cells. Recent studies further indicate that this signalling system plays important roles in engraftment of hematopoietic stem cells as well as in tumour immune surveillance through regulation of the phagocytic activity of macrophages. In the immune system, the CD47-SIRPα interaction is also important for the development of a subset of CD11c(+)DCs as well as organization of secondary lymphoid organs. Finally, the CD47-SIRPα signalling system likely regulates bone homeostasis by osteoclast development. Newly emerged functions of the CD47-SIRPα signalling system thus provide multiple therapeutic strategies for cancer, autoimmune diseases and bone disorders.
authors.affiliation: Department of Biochemistry and Molecular Biology, Division of Molecular and Cellular Signaling, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; and Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa-Machi, Maebashi, Gunma 371-8514, Japan ymurata@med.kobe-u.ac.jp.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Murata
authors.affiliation: Department of Biochemistry and Molecular Biology, Division of Molecular and Cellular Signaling, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; and Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa-Machi, Maebashi, Gunma 371-8514, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Kotani
authors.affiliation: Department of Biochemistry and Molecular Biology, Division of Molecular and Cellular Signaling, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; and Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa-Machi, Maebashi, Gunma 371-8514, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohnishi
authors.affiliation: Department of Biochemistry and Molecular Biology, Division of Molecular and Cellular Signaling, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; and Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa-Machi, Maebashi, Gunma 371-8514, Japan matozaki@med.kobe-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matozaki
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism*; D001842:Bone and Bones / Q000502:physiology*; D051928:CD47 Antigen / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D007107:Immune System / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D010587:Phagocytosis; D011971:Receptors, Immunologic / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000943:Antigens, Differentiation; D051928:CD47 Antigen; C497894:CD47 protein, human; D011971:Receptors, Immunologic; C501920:SIRPA protein, human
keywords: CD47–SIRPα system; cancer therapy; dendritic cell; macrophage; phagocytosis