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Bunker EN, Le Guerroué F, Wang C, Strub M, Werner A, Tjandra N, Youle RJ. Nix interacts with WIPI2 to induce mitophagy. EMBO J 2023; 42:e113491. [PMID: 37621214 PMCID: PMC10646555 DOI: 10.15252/embj.2023113491] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 07/13/2023] [Accepted: 07/15/2023] [Indexed: 08/26/2023] Open
Abstract
Nix is a membrane-anchored outer mitochondrial protein that induces mitophagy. While Nix has an LC3-interacting (LIR) motif that binds to ATG8 proteins, it also contains a minimal essential region (MER) that induces mitophagy through an unknown mechanism. We used chemically induced dimerization (CID) to probe the mechanism of Nix-mediated mitophagy and found that both the LIR and MER are required for robust mitophagy. We find that the Nix MER interacts with the autophagy effector WIPI2 and recruits WIPI2 to mitochondria. The Nix LIR motif is also required for robust mitophagy and converts a homogeneous WIPI2 distribution on the surface of the mitochondria into puncta, even in the absence of ATG8s. Together, this work reveals unanticipated mechanisms in Nix-induced mitophagy and the elusive role of the MER, while also describing an interesting example of autophagy induction that acts downstream of the canonical initiation complexes.
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Affiliation(s)
- Eric N Bunker
- Surgical Neurology BranchNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - François Le Guerroué
- Surgical Neurology BranchNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Chunxin Wang
- Surgical Neurology BranchNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Marie‐Paule Strub
- Biochemistry and Biophysics CenterNational Heart, Lung, and Blood Institute, National Institutes of HealthBethesdaMDUSA
| | - Achim Werner
- Stem Cell Biochemistry UnitNational Institute of Dental and Craniofacial Research, National Institutes of HealthBethesdaMDUSA
| | - Nico Tjandra
- Biochemistry and Biophysics CenterNational Heart, Lung, and Blood Institute, National Institutes of HealthBethesdaMDUSA
| | - Richard J Youle
- Surgical Neurology BranchNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
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Fischer TD, Bunker EN, Zhu PP, Le Guerroué F, Dominguez-Martin E, Scavone F, Cohen R, Yao T, Wang Y, Werner A, Youle RJ. STING induces LUBAC-mediated synthesis of linear ubiquitin chains to stimulate innate immune signaling. bioRxiv 2023:2023.10.14.562349. [PMID: 37873486 PMCID: PMC10592814 DOI: 10.1101/2023.10.14.562349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
STING activation by cyclic dinucleotides in mammals induces interferon- and NFκB -related gene expression, and the lipidation of LC3B at Golgi membranes. While mechanisms of the interferon response are well understood, the mechanisms of NFκB activation mediated by STING remain unclear. We report that STING activation induces K63- and M1-linked/linear ubiquitin chain formation at LC3B-associated Golgi membranes. Loss of the LUBAC E3 ubiquitin ligase prevents formation of linear, but not K63-linked ubiquitin chains or STING activation and inhibits STING-induced NFκB and IRF3-mediated signaling in monocytic THP1 cells. The proton channel activity of STING is also important for both K63 and linear ubiquitin chain formation, and NFκB- and interferon-related gene expression. Thus, LUBAC synthesis of linear ubiquitin chains regulates STING-mediated innate immune signaling.
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Affiliation(s)
- Tara D. Fischer
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, MD, USA
| | - Eric N. Bunker
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, MD, USA
| | - Peng-Peng Zhu
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, MD, USA
| | - François Le Guerroué
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, MD, USA
| | - Eunice Dominguez-Martin
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, MD, USA
| | - Francesco Scavone
- Department of Biochemistry and Molecular Biology, Colorado State University; Fort Collins, CO, USA
| | - Robert Cohen
- Department of Biochemistry and Molecular Biology, Colorado State University; Fort Collins, CO, USA
| | - Tingting Yao
- Department of Biochemistry and Molecular Biology, Colorado State University; Fort Collins, CO, USA
| | - Yan Wang
- Mass Spectrometry, National Institute of Dental and Craniofacial Research, National Institutes of Health; Bethesda, MD, USA
| | - Achim Werner
- Stem Cell Biochemistry Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health; Bethesda, MD, USA
| | - Richard J. Youle
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, MD, USA
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Le Guerroué F, Bunker EN, Rosencrans WM, Nguyen JT, Basar MA, Werner A, Chou TF, Wang C, Youle RJ. TNIP1 inhibits selective autophagy via bipartite interaction with LC3/GABARAP and TAX1BP1. Mol Cell 2023; 83:927-941.e8. [PMID: 36898370 PMCID: PMC10112281 DOI: 10.1016/j.molcel.2023.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 01/17/2023] [Accepted: 02/17/2023] [Indexed: 03/12/2023]
Abstract
Mitophagy is a form of selective autophagy that disposes of superfluous and potentially damage-inducing organelles in a tightly controlled manner. While the machinery involved in mitophagy induction is well known, the regulation of the components is less clear. Here, we demonstrate that TNIP1 knockout in HeLa cells accelerates mitophagy rates and that ectopic TNIP1 negatively regulates the rate of mitophagy. These functions of TNIP1 depend on an evolutionarily conserved LIR motif as well as an AHD3 domain, which are required for binding to the LC3/GABARAP family of proteins and the autophagy receptor TAX1BP1, respectively. We further show that phosphorylation appears to regulate its association with the ULK1 complex member FIP200, allowing TNIP1 to compete with autophagy receptors, which provides a molecular rationale for its inhibitory function during mitophagy. Taken together, our findings describe TNIP1 as a negative regulator of mitophagy that acts at the early steps of autophagosome biogenesis.
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Affiliation(s)
- François Le Guerroué
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eric N Bunker
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - William M Rosencrans
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jack T Nguyen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mohammed A Basar
- Stem Cell Biochemistry Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Achim Werner
- Stem Cell Biochemistry Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tsui-Fen Chou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Chunxin Wang
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard J Youle
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Wheeler GE, Purkayastha A, Bunker EN, Bortz DM, Liu X. Protocol for Analysis and Consolidation of TrackMate Outputs for Measuring Two-Dimensional Cell Motility using Nuclear Tracking. J Vis Exp 2021. [PMID: 34978296 DOI: 10.3791/62885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Collective cellular migration plays a key role in many fundamental biological processes including development, wound healing, and cancer metastasis. To understand the regulation of cell motility, we must be able to measure it easily and consistently under different conditions. Here we describe a method for measuring and quantifying single-cell and bulk motility of HaCaT keratinocytes using a nuclear stain. This method includes a MATLAB script for analyzing TrackMate output files to calculate displacements, motility rates, and trajectory angles in single cells and in bulk for an imaging site. This motility analysis script allows for quick, straightforward, and scalable analysis of cell motility rates from TrackMate data and could be broadly used to identify and study the regulation of motility in epithelial cells. We also provide a MATLAB script for reorganizing microscopy videos collected on a microscope and converting them to TIF stacks, which can be analyzed using the ImageJ TrackMate plugin in bulk. Using this methodology to explore the roles of adherens junctions and actin cytoskeletal dynamics in regulating cell motility in HaCaT keratinocytes, we demonstrate evidence that Arp2/3 activity is required for the elevated motility seen after α-catenin depletion in HaCaT keratinocytes.
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Affiliation(s)
| | | | - Eric N Bunker
- Department of Biochemistry, University of Colorado Boulder
| | - David M Bortz
- Department of Applied Mathematics, University of Colorado Boulder
| | - Xuedong Liu
- Department of Biochemistry, University of Colorado Boulder
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Bunker EN, Wheeler GE, Chapnick DA, Liu X. Suppression of α-catenin and adherens junctions enhances epithelial cell proliferation and motility via TACE-mediated TGF-α autocrine/paracrine signaling. Mol Biol Cell 2020; 32:348-361. [PMID: 33378218 PMCID: PMC8098817 DOI: 10.1091/mbc.e19-08-0474] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sustained cell migration is essential for wound healing and cancer metastasis. The epidermal growth factor receptor (EGFR) signaling cascade is known to drive cell migration and proliferation. While the signal transduction downstream of EGFR has been extensively investigated, our knowledge of the initiation and maintenance of EGFR signaling during cell migration remains limited. The metalloprotease TACE (tumor necrosis factor alpha converting enzyme) is responsible for producing active EGFR family ligands in the via ligand shedding. Sustained TACE activity may perpetuate EGFR signaling and reduce a cell’s reliance on exogenous growth factors. Using a cultured keratinocyte model system, we show that depletion of α-catenin perturbs adherens junctions, enhances cell proliferation and motility, and decreases dependence on exogenous growth factors. We show that the underlying mechanism for these observed phenotypical changes depends on enhanced autocrine/paracrine release of the EGFR ligand transforming growth factor alpha in a TACE-dependent manner. We demonstrate that proliferating keratinocyte epithelial cell clusters display waves of oscillatory extracellular signal–regulated kinase (ERK) activity, which can be eliminated by TACE knockout, suggesting that these waves of oscillatory ERK activity depend on autocrine/paracrine signals produced by TACE. These results provide new insights into the regulatory role of adherens junctions in initiating and maintaining autocrine/paracrine signaling with relevance to wound healing and cellular transformation.
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Affiliation(s)
- Eric N Bunker
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | - Graycen E Wheeler
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | | | - Xuedong Liu
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
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Sanchez GJ, Richmond PA, Bunker EN, Karman SS, Azofeifa J, Garnett AT, Xu Q, Wheeler GE, Toomey CM, Zhang Q, Dowell RD, Liu X. Genome-wide dose-dependent inhibition of histone deacetylases studies reveal their roles in enhancer remodeling and suppression of oncogenic super-enhancers. Nucleic Acids Res 2019; 46:1756-1776. [PMID: 29240919 PMCID: PMC5829637 DOI: 10.1093/nar/gkx1225] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/08/2017] [Indexed: 12/22/2022] Open
Abstract
Histone deacetylase inhibitors (HDACIs) are known to alter gene expression by both up- and down-regulation of protein-coding genes in normal and cancer cells. However, the exact regulatory mechanisms of action remain uncharacterized. Here we investigated genome wide dose-dependent epigenetic and transcriptome changes in response to HDACI largazole in a transformed and a non-transformed cell line. Exposure to low nanomolar largazole concentrations (<GI50) predominantly resulted in upregulation of gene transcripts whereas higher largazole doses (≥GI50) triggered a general decrease in mRNA accumulation. Largazole induces elevation of histone H3 acetylation at Lys-9 and Lys-27 along many gene bodies but does not correlate with up- or down-regulation of the associated transcripts. A higher dose of largazole results in more RNA polymerase II pausing at the promoters of actively transcribed genes and cell death. The most prevalent changes associated with transcriptional regulation occur at distal enhancer elements. Largazole promotes H3K27 acetylation at a subset of poised enhancers and unexpectedly, we also found active enhancers that become decommissioned in a dose and cell type-dependent manner. In particular, largazole decreases RNA polymerase II accumulation at super-enhancers (SEs) and preferentially suppresses SE-driven transcripts that are associated with oncogenic activities in transformed cells.
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Affiliation(s)
- Gilson J Sanchez
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Phillip A Richmond
- BioFrontiers Institute and IQ Biology Program, University of Colorado-Boulder, Boulder, CO 80303, USA.,Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Eric N Bunker
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Samuel S Karman
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Joseph Azofeifa
- BioFrontiers Institute and IQ Biology Program, University of Colorado-Boulder, Boulder, CO 80303, USA
| | - Aaron T Garnett
- Ecology and Evolutionary Biology, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Quanbin Xu
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Graycen E Wheeler
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Cathryn M Toomey
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Qinghong Zhang
- Department of Dermatology, University of Colorado Denver, Aurora, CO 80045, USA
| | - Robin D Dowell
- BioFrontiers Institute and IQ Biology Program, University of Colorado-Boulder, Boulder, CO 80303, USA.,Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309, USA
| | - Xuedong Liu
- Department of Chemistry and Biochemistry, University of Colorado-Boulder, Boulder, CO 80309, USA
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