title: B Lymphocyte-Specific Loss of Ric-8A Results in a Gα Protein Deficit and Severe Humoral Immunodeficiency.
abstract: Resistance to inhibitors of cholinesterase 8A (Ric-8A) is a highly evolutionarily conserved cytosolic protein initially identified in Caenorhabditis elegans, where it was assigned a regulatory role in asymmetric cell divisions. It functions as a guanine nucleotide exchange factor for Gαi, Gαq, and Gα12/13 and as a molecular chaperone required for the initial association of nascent Gα subunits with cellular membranes in embryonic stem cell lines. To test its role in hematopoiesis and B lymphocytes specifically, we generated ric8 (fl/fl) vav1-cre and ric8 (fl/fl) mb1-cre mice. The major hematopoietic cell lineages developed in the ric8 (fl/fl) vav1-cre mice, notwithstanding severe reduction in Gαi2/3, Gαq, and Gα13 proteins. B lymphocyte-specific loss of Ric-8A did not compromise bone marrow B lymphopoiesis, but splenic marginal zone B cell development failed, and B cells underpopulated lymphoid organs. The ric8 (fl/fl) mb1-cre B cells exhibited poor responses to chemokines, abnormal trafficking, improper in situ positioning, and loss of polarity components during B cell differentiation. The ric8 (fl/fl) mb1-cre mice had a severely disrupted lymphoid architecture and poor primary and secondary Ab responses. In B lymphocytes, Ric-8A is essential for normal Gα protein levels and is required for B cell differentiation, trafficking, and Ab responses.
authors.affiliation: B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Cedric
authors.initials: C
authors.lastname: Boularan
authors.affiliation: B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Hwang
authors.affiliation: B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Olena
authors.initials: O
authors.lastname: Kamenyeva
authors.affiliation: B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Chung
authors.initials: C
authors.lastname: Park
authors.affiliation: B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Kathleen
authors.initials: K
authors.lastname: Harrison
authors.affiliation: Department of Neurology, University of Wisconsin-Madison, Madison, WI 53706; and Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huang
authors.affiliation: B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892; jkehrl@niaid.nih.gov.
authors.forename: John H
authors.initials: JH
authors.lastname: Kehrl
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western; D002118:Calcium / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D051960:GTP-Binding Protein alpha Subunit, Gi2 / Q000276:immunology* / Q000378:metabolism; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000276:immunology* / Q000378:metabolism; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000276:immunology* / Q000378:metabolism; D018858:Germinal Center / Q000276:immunology / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000378:metabolism; D056724:Immunity, Humoral / Q000235:genetics / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016511:Severe Combined Immunodeficiency / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D059008:Time-Lapse Imaging
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D051567:Proto-Oncogene Proteins c-vav; C485884:Ric8a protein, mouse; C496619:Vav1 protein, mouse; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; C498016:Gnai2 protein, mouse; C417708:Gnai3 protein, mouse; D002118:Calcium