title: A motif in LILRB2 critical for Angptl2 binding and activation.
abstract: A better understanding of the interaction between extrinsic factors and surface receptors on stem cells will greatly benefit stem cell research and applications. Recently, we showed that several angiopoietin-like proteins (Angptls) bind and activate the immune inhibitory receptor human leukocyte immunoglobulin (Ig)-like receptor B2 (LILRB2) to support ex vivo expansion of hematopoietic stem cells (HSCs) and leukemia development. However, the molecular basis for the interaction between Angptls and LILRB2 was unclear. Here, we demonstrate that Angptl2 expressed in mammalian cells forms high-molecular-weight species and that ligand multimerization is required for activation of LILRB2 for downstream signaling. A novel motif in the first and fourth Ig domains of LILRB2 was identified that is necessary for the receptor to be bound and activated by Angptl2. The binding of Angptl2 to LILRB2 is more potent than and not completely overlapped with the binding of another ligand, HLA-G. Immobilized anti-LILRB2 antibodies induce a more potent activation of LILRB2 than Angptl2, and we developed a serum-free culture containing defined cytokines and immobilized anti-LILRB2 that supports a net expansion of repopulating human cord blood HSCs. Our elucidation of the mode of Angptl binding to LILRB2 enabled the development of a new approach for ex vivo expansion of human HSCs.
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX;
authors.forename: Mi
authors.initials: M
authors.lastname: Deng
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX; Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Shenzhen Graduate School of Peking University, Shenzhen, China;
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX; Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China;
authors.forename: Junke
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX;
authors.forename: Xuan
authors.initials: X
authors.lastname: Wan
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX;
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, World Premier International Immunology Frontier Research Center, Osaka University, and Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Osaka, Japan;
authors.forename: Kouyuki
authors.initials: K
authors.lastname: Hirayasu
authors.affiliation: National Institute of Biological Sciences, Beijing, China;
authors.forename: Hanzi
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX;
authors.forename: Yeeling
authors.initials: Y
authors.lastname: Lam
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX;
authors.forename: Liping
authors.initials: L
authors.lastname: Chen
authors.affiliation: Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China;
authors.forename: Qihui
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Shandong University and National New Drug R&D Center in Shandong, Jinan, China; and.
authors.forename: Chun
authors.initials: C
authors.lastname: Song
authors.affiliation: National Institute of Biological Sciences, Beijing, China;
authors.forename: Niu
authors.initials: N
authors.lastname: Huang
authors.affiliation: Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China;
authors.forename: George F
authors.initials: GF
authors.lastname: Gao
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX;
authors.forename: Youxing
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, World Premier International Immunology Frontier Research Center, Osaka University, and Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Osaka, Japan;
authors.forename: Hisashi
authors.initials: H
authors.lastname: Arase
authors.affiliation: Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX; Department of Developmental Biology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Cheng Cheng
authors.initials: CC
authors.lastname: Zhang
mesh_terms: D000091302:Angiopoietin-Like Protein 2; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D005312:Fetal Blood / Q000166:cytology / Q000378:metabolism; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D064593:Heterografts; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: C485792:ANGPTL2 protein, human; D000091302:Angiopoietin-Like Protein 2; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; C491341:LILRB2 protein, human; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins