title: Comparative genetic screens in human cells reveal new regulatory mechanisms in WNT signaling.
abstract: The comprehensive understanding of cellular signaling pathways remains a challenge due to multiple layers of regulation that may become evident only when the pathway is probed at different levels or critical nodes are eliminated. To discover regulatory mechanisms in canonical WNT signaling, we conducted a systematic forward genetic analysis through reporter-based screens in haploid human cells. Comparison of screens for negative, attenuating and positive regulators of WNT signaling, mediators of R-spondin-dependent signaling and suppressors of constitutive signaling induced by loss of the tumor suppressor adenomatous polyposis coli or casein kinase 1α uncovered new regulatory features at most levels of the pathway. These include a requirement for the transcription factor AP-4, a role for the DAX domain of AXIN2 in controlling β-catenin transcriptional activity, a contribution of glycophosphatidylinositol anchor biosynthesis and glypicans to R-spondin-potentiated WNT signaling, and two different mechanisms that regulate signaling when distinct components of the β-catenin destruction complex are lost. The conceptual and methodological framework we describe should enable the comprehensive understanding of other signaling systems.
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.|Department of Medicine, Stanford University School of Medicine, Stanford, United States.
authors.forename: Andres M
authors.identifier: 0000-0002-4224-8819
authors.initials: AM
authors.lastname: Lebensohn
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.|Department of Medicine, Stanford University School of Medicine, Stanford, United States.
authors.forename: Ramin
authors.initials: R
authors.lastname: Dubey
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States.
authors.forename: Leif R
authors.initials: LR
authors.lastname: Neitzel
authors.affiliation: Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, United States.
authors.forename: Ofelia
authors.initials: O
authors.lastname: Tacchelly-Benites
authors.affiliation: Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, United States.
authors.forename: Eungi
authors.initials: E
authors.lastname: Yang
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 Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, United States.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Davis
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.|Department of Medicine, Stanford University School of Medicine, Stanford, United States.
authors.forename: Bhaven B
authors.initials: BB
authors.lastname: Patel
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, United States.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Bahrami-Nejad
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Travaglini
authors.affiliation: Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, United States.
authors.forename: Yashi
authors.initials: Y
authors.lastname: Ahmed
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States.
authors.forename: Ethan
authors.initials: E
authors.lastname: Lee
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: Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.|Department of Medicine, Stanford University School of Medicine, Stanford, United States.
authors.forename: Rajat
authors.identifier: 0000-0001-7609-8858
authors.initials: R
authors.lastname: Rohatgi
mesh_terms: D047389:Casein Kinase I / Q000172:deficiency; D003598:Cytoskeletal Proteins / Q000172:deficiency; D005786:Gene Expression Regulation; D053263:Gene Regulatory Networks; D017930:Genes, Reporter; D005820:Genetic Testing / Q000379:methods*; D006238:Haploidy; D006801:Humans; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D060449:Wnt Signaling Pathway
chemical_list: C115681:APC2 protein, human; D003598:Cytoskeletal Proteins; D051153:Wnt Proteins; D047389:Casein Kinase I
keywords: APC; AXIN; CSNK1A1; GPC4; GPI; HAP1; HUWE1; RSPO; SERBP1; TFAP4; WNT signaling; computational biology; developmental biology; forward genetics; genetic screen; glypican; haploid cells; haploid screen; human; stem cells; suppressor screen; systems biology