title: APS, an adaptor molecule containing PH and SH2 domains, has a negative regulatory role in B cell proliferation.
abstract: Adaptor molecule containing PH and SH2 domains (APS) is an intracellular adaptor protein that forms part of an adaptor family along with Lnk and SH2-B. APS transcripts are expressed in various tissues including brain, kidney, and muscle, as well as in splenic B cells but not in T cells. We investigated the functions of APS in B cell development and activation by generating APS-transgenic (APS-Tg) mice that overexpressed APS in lymphocytes. The number of B-1 cells in the peritoneal cavity was reduced in APS-Tg mice, as were B-2 cells in the spleen. B cell development in the bone marrow was partially impaired at the transition stage from proliferating large pre-B to small pre-B cells. B cell proliferation induced by B cell receptor (BCR) crosslinking but not by other B cell mitogens was also impaired in APS-Tg mice. APS co-localized with BCR complexes and filamentous actin in activated APS-Tg B cells. Thus, APS appears to play novel negative regulatory roles in BCR signaling, actin reorganization pathways, and control of compartment sizes of B-lineage cells.
authors.affiliation: Division of Immunology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Iseki
authors.forename: Chiyomi
authors.initials: C
authors.lastname: Kubo-Akashi
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kwon
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takatsu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takaki
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D002454:Cell Differentiation; D019070:Cell Lineage; D049109:Cell Proliferation; D002478:Cells, Cultured; D008213:Lymphocyte Activation; D051379:Mice; D008822:Mice, Transgenic; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing