title: A forward genetic screen reveals novel independent regulators of ULBP1, an activating ligand for natural killer cells.
abstract: Recognition and elimination of tumor cells by the immune system is crucial for limiting tumor growth. Natural killer (NK) cells become activated when the receptor NKG2D is engaged by ligands that are frequently upregulated in primary tumors and on cancer cell lines. However, the molecular mechanisms driving NKG2D ligand expression on tumor cells are not well defined. Using a forward genetic screen in a tumor-derived human cell line, we identified several novel factors supporting expression of the NKG2D ligand ULBP1. Our results show stepwise contributions of independent pathways working at multiple stages of ULBP1 biogenesis. Deeper investigation of selected hits from the screen showed that the transcription factor ATF4 drives ULBP1 gene expression in cancer cell lines, while the RNA-binding protein RBM4 supports ULBP1 expression by suppressing a novel alternatively spliced isoform of ULBP1 mRNA. These findings offer insight into the stress pathways that alert the immune system to danger.
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Gowen
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, United States.
authors.forename: Bryan
authors.initials: B
authors.lastname: Chim
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States.
authors.forename: Caleb D
authors.initials: CD
authors.lastname: Marceau
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Trever T
authors.initials: TT
authors.lastname: Greene
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, United States.
authors.forename: Patrick
authors.initials: P
authors.lastname: Burr
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Jeanmarie R
authors.initials: JR
authors.lastname: Gonzalez
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Hesser
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Dietzen
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Teal
authors.initials: T
authors.lastname: Russell
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Iannello
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: Laurent
authors.initials: L
authors.lastname: Coscoy
authors.affiliation: Center for Synthetic Immunity, Department of Microbiology and Immunology, Dartmouth Geisel School of Medicine, Lebanon, United States.
authors.forename: Charles L
authors.initials: CL
authors.lastname: Sentman
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States.
authors.forename: Jan E
authors.initials: JE
authors.lastname: Carette
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, United States.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Muljo
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, Berkeley, United States.
authors.forename: David H
authors.initials: DH
authors.lastname: Raulet
mesh_terms: D051701:Activating Transcription Factor 4 / Q000378:metabolism; D045744:Cell Line, Tumor; D058851:GPI-Linked Proteins / Q000235:genetics / Q000378:metabolism; D005820:Genetic Testing; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism
chemical_list: C497109:ATF4 protein, human; D058851:GPI-Linked Proteins; D047908:Intracellular Signaling Peptides and Proteins; C527085:KLRK1 protein, human; D055655:NK Cell Lectin-Like Receptor Subfamily K; C473692:RBM4 protein, human; D016601:RNA-Binding Proteins; C423231:ULBP1 protein, human; D051701:Activating Transcription Factor 4
keywords: CRISPR/Cas9; NKG2D; alternative splicing; cellular stress; human; immunology; natural killer cells; tumor immunology