1
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Heindel AJ, Brulet JW, Wang X, Founds MW, Libby AH, Bai DL, Lemke MC, Leace DM, Harris TE, Hafner M, Hsu KL. Chemoproteomic capture of RNA binding activity in living cells. Nat Commun 2023; 14:6282. [PMID: 37805600 PMCID: PMC10560261 DOI: 10.1038/s41467-023-41844-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 09/20/2023] [Indexed: 10/09/2023] Open
Abstract
Proteomic methods for RNA interactome capture (RIC) rely principally on crosslinking native or labeled cellular RNA to enrich and investigate RNA-binding protein (RBP) composition and function in cells. The ability to measure RBP activity at individual binding sites by RIC, however, has been more challenging due to the heterogenous nature of peptide adducts derived from the RNA-protein crosslinked site. Here, we present an orthogonal strategy that utilizes clickable electrophilic purines to directly quantify protein-RNA interactions on proteins through photoaffinity competition with 4-thiouridine (4SU)-labeled RNA in cells. Our photo-activatable-competition and chemoproteomic enrichment (PACCE) method facilitated detection of >5500 cysteine sites across ~3000 proteins displaying RNA-sensitive alterations in probe binding. Importantly, PACCE enabled functional profiling of canonical RNA-binding domains as well as discovery of moonlighting RNA binding activity in the human proteome. Collectively, we present a chemoproteomic platform for global quantification of protein-RNA binding activity in living cells.
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Affiliation(s)
- Andrew J Heindel
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Jeffrey W Brulet
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
| | - Xiantao Wang
- RNA Molecular Biology Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, MD, 20892, USA
| | - Michael W Founds
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
| | - Adam H Libby
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
- University of Virginia Cancer Center, University of Virginia, Charlottesville, VA, 22903, USA
| | - Dina L Bai
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
| | - Michael C Lemke
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - David M Leace
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Markus Hafner
- RNA Molecular Biology Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, MD, 20892, USA
| | - Ku-Lung Hsu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.
- University of Virginia Cancer Center, University of Virginia, Charlottesville, VA, 22903, USA.
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22908, USA.
- Department of Chemistry, University of Texas at Austin, Austin, TX, 78712, USA.
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2
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Li H, Fu X, Zhao J, Li C, Li L, Xia P, Guo J, Wei W, Zeng R, Wu J, Sun Y, Huang L, Wang X. EXOC4 Promotes Diffuse-Type Gastric Cancer Metastasis via Activating FAK Signal. Mol Cancer Res 2022; 20:1021-1034. [PMID: 35471457 PMCID: PMC9381130 DOI: 10.1158/1541-7786.mcr-21-0441] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/01/2021] [Accepted: 03/17/2022] [Indexed: 01/07/2023]
Abstract
In comparison with intestinal-type gastric cancer, diffuse-type gastric cancer (DGC) is more likely to recur, metastasize, and exhibit worse clinical outcomes; however, the underlying mechanism of DGC recurrence remains elusive. By employing an LC/MS-MS proteomic approach, we identified that exocyst complex component 4 (EXOC4) was significantly upregulated in DGC with recurrence, compared to those with nonrecurrence. High expression of EXOC4 was correlated with tumor metastasis and poor prognosis in patients with DGC. Moreover, EXOC4 promoted cell migration and invasion as well as the tumor metastasis of DGC cells. Mechanistically, EXOC4 regulated the phosphorylation of focal adhesion kinase (FAK) at Y397 sites by stimulating the secretion of integrin α5/β1/EGF and enhancing the interaction of FAK and integrin or EGFR. The FAK inhibitor VS-4718 reversed the metastasis mediated by EXOC4 overexpression and suppressed the tumor growth of patient-derived xenografts derived from DGC with high EXOC4 expression. The EXOC4-FAK axis could be a potential therapeutic target for patients with DGC with high expression of EXOC4. IMPLICATIONS The EXOC4-FAK axis promoted DGC metastasis and could be a potential therapeutic target for patients with DGC.
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Affiliation(s)
- Haojie Li
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China
| | - Xuhong Fu
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junjie Zhao
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China
| | - Chen Li
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lingmeng Li
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Peiyan Xia
- University of Michigan-Shanghai Jiaotong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Jianping Guo
- Institute of Precision Medicine, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Rong Zeng
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jiarui Wu
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Yihong Sun
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Liyu Huang
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
| | - Xuefei Wang
- Department of General Surgery, Zhongshan Hospital, General Surgery Research Institute, Fudan University, Shanghai, China.,Corresponding Authors: Xuefei Wang, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7224; E-mail: ; Jiarui Wu, Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Phone: 212-030-5000; Fax: 212-032-5034; E-mail: ; Yihong Sun, Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai 200032, China. Phone: 216-404-1990; Fax: 216-403-7269; E-mail: ; and Liyu Huang, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Phone: 213-420-7042; E-mail:
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3
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Zaman A, Wu X, Lemoff A, Yadavalli S, Lee J, Wang C, Cooper J, McMillan EA, Yeaman C, Mirzaei H, White MA, Bivona TG. Exocyst protein subnetworks integrate Hippo and mTOR signaling to promote virus detection and cancer. Cell Rep 2021; 36:109491. [PMID: 34348154 DOI: 10.1016/j.celrep.2021.109491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 05/20/2021] [Accepted: 07/14/2021] [Indexed: 11/25/2022] Open
Abstract
The exocyst is an evolutionarily conserved protein complex that regulates vesicular trafficking and scaffolds signal transduction. Key upstream components of the exocyst include monomeric RAL GTPases, which help mount cell-autonomous responses to trophic and immunogenic signals. Here, we present a quantitative proteomics-based characterization of dynamic and signal-dependent exocyst protein interactomes. Under viral infection, an Exo84 exocyst subcomplex assembles the immune kinase Protein Kinase R (PKR) together with the Hippo kinase Macrophage Stimulating 1 (MST1). PKR phosphorylates MST1 to activate Hippo signaling and inactivate Yes Associated Protein 1 (YAP1). By contrast, a Sec5 exocyst subcomplex recruits another immune kinase, TANK binding kinase 1 (TBK1), which interacted with and activated mammalian target of rapamycin (mTOR). RALB was necessary and sufficient for induction of Hippo and mTOR signaling through parallel exocyst subcomplex engagement, supporting the cellular response to virus infection and oncogenic signaling. This study highlights RALB-exocyst signaling subcomplexes as mechanisms for the integrated engagement of Hippo and mTOR signaling in cells challenged by viral pathogens or oncogenic signaling.
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Affiliation(s)
- Aubhishek Zaman
- Department of Medicine, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA; UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA.
| | - Xiaofeng Wu
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Andrew Lemoff
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Sivaramakrishna Yadavalli
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Jeon Lee
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA; Bioinformatics Core Facility, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Chensu Wang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Jonathan Cooper
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Elizabeth A McMillan
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Charles Yeaman
- Department of Anatomy and Cell Biology, University of Iowa, 51 Newton Road, Iowa City, IA 52242, USA
| | - Hamid Mirzaei
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Michael A White
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Trever G Bivona
- Department of Medicine, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA; UCSF Helen Diller Comprehensive Cancer Center, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA.
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4
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Banday S, Pandita RK, Mushtaq A, Bacolla A, Mir US, Singh DK, Jan S, Bhat KP, Hunt CR, Rao G, Charaka VK, Tainer JA, Pandita TK, Altaf M. Autism-Associated Vigilin Depletion Impairs DNA Damage Repair. Mol Cell Biol 2021; 41:e0008221. [PMID: 33941620 PMCID: PMC8224237 DOI: 10.1128/mcb.00082-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/17/2021] [Accepted: 04/28/2021] [Indexed: 12/24/2022] Open
Abstract
Vigilin (Vgl1) is essential for heterochromatin formation, chromosome segregation, and mRNA stability and is associated with autism spectrum disorders and cancer: vigilin, for example, can suppress proto-oncogene c-fms expression in breast cancer. Conserved from yeast to humans, vigilin is an RNA-binding protein with 14 tandemly arranged nonidentical hnRNP K-type homology (KH) domains. Here, we report that vigilin depletion increased cell sensitivity to cisplatin- or ionizing radiation (IR)-induced cell death and genomic instability due to defective DNA repair. Vigilin depletion delayed dephosphorylation of IR-induced γ-H2AX and elevated levels of residual 53BP1 and RIF1 foci, while reducing Rad51 and BRCA1 focus formation, DNA end resection, and double-strand break (DSB) repair. We show that vigilin interacts with the DNA damage response (DDR) proteins RAD51 and BRCA1, and vigilin depletion impairs their recruitment to DSB sites. Transient hydroxyurea (HU)-induced replicative stress in vigilin-depleted cells increased replication fork stalling and blocked restart of DNA synthesis. Furthermore, histone acetylation promoted vigilin recruitment to DSBs preferentially in the transcriptionally active genome. These findings uncover a novel vigilin role in DNA damage repair with implications for autism and cancer-related disorders.
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Affiliation(s)
- Shahid Banday
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Raj K. Pandita
- Houston Methodist Research Institute, Houston, Texas, USA
- Baylor College of Medicine, Houston, Texas, USA
| | - Arjamand Mushtaq
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Ulfat Syed Mir
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | | | - Sadaf Jan
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Krishna P. Bhat
- Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | | | - Ganesh Rao
- Baylor College of Medicine, Houston, Texas, USA
| | | | - John A. Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
- Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Tej K. Pandita
- Houston Methodist Research Institute, Houston, Texas, USA
- Baylor College of Medicine, Houston, Texas, USA
| | - Mohammad Altaf
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India
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5
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Cancer-driving mutations and variants of components of the membrane trafficking core machinery. Life Sci 2020; 264:118662. [PMID: 33127517 DOI: 10.1016/j.lfs.2020.118662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/17/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022]
Abstract
The core machinery for vesicular membrane trafficking broadly comprises of coat proteins, RABs, tethering complexes and SNAREs. As cellular membrane traffic modulates key processes of mitogenic signaling, cell migration, cell death and autophagy, its dysregulation could potentially results in increased cell proliferation and survival, or enhanced migration and invasion. Changes in the levels of some components of the core machinery of vesicular membrane trafficking, likely due to gene amplifications and/or alterations in epigenetic factors (such as DNA methylation and micro RNA) have been extensively associated with human cancers. Here, we provide an overview of association of membrane trafficking with cancer, with a focus on mutations and variants of coat proteins, RABs, tethering complex components and SNAREs that have been uncovered in human cancer cells/tissues. The major cellular and molecular cancer-driving or suppression mechanisms associated with these components of the core membrane trafficking machinery shall be discussed.
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6
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Ahmed SM, Nishida-Fukuda H, Li Y, McDonald WH, Gradinaru CC, Macara IG. Exocyst dynamics during vesicle tethering and fusion. Nat Commun 2018; 9:5140. [PMID: 30510181 PMCID: PMC6277416 DOI: 10.1038/s41467-018-07467-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/01/2018] [Indexed: 11/15/2022] Open
Abstract
The exocyst is a conserved octameric complex that tethers exocytic vesicles to the plasma membrane prior to fusion. Exocyst assembly and delivery mechanisms remain unclear, especially in mammalian cells. Here we tagged multiple endogenous exocyst subunits with sfGFP or Halo using Cas9 gene-editing, to create single and double knock-in lines of mammary epithelial cells, and interrogated exocyst dynamics by high-speed imaging and correlation spectroscopy. We discovered that mammalian exocyst is comprised of tetrameric subcomplexes that can associate independently with vesicles and plasma membrane and are in dynamic equilibrium with octamer and monomers. Membrane arrival times are similar for subunits and vesicles, but with a small delay (~80msec) between subcomplexes. Departure of SEC3 occurs prior to fusion, whereas other subunits depart just after fusion. About 9 exocyst complexes are associated per vesicle. These data reveal the mammalian exocyst as a remarkably dynamic two-part complex and provide important insights into assembly/disassembly mechanisms. Exocyst complex tethers vesicles to plasma membranes, but assembly mechanisms remain unclear. Here, the authors use Cas9 gene editing to tag exocyst components in epithelial cells, and find that exocyst subcomplexes are recruited to membranes independently, but are both needed for vesicle fusion.
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Affiliation(s)
- Syed Mukhtar Ahmed
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.
| | - Hisayo Nishida-Fukuda
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.,Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime, 7910295, Japan.,Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, Toon, Ehime, 7910295, Japan.,Department of Genome Editing, Institute of Biomedical Sciences, Kansai Medical University, Hirakata, 5731010, Japan
| | - Yuchong Li
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.,Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - W Hayes McDonald
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.,Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Ian G Macara
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.
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7
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Horikoshi N, Pandita RK, Mujoo K, Hambarde S, Sharma D, Mattoo AR, Chakraborty S, Charaka V, Hunt CR, Pandita TK. β2-spectrin depletion impairs DNA damage repair. Oncotarget 2018; 7:33557-70. [PMID: 27248179 PMCID: PMC5085102 DOI: 10.18632/oncotarget.9677] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/20/2016] [Indexed: 12/22/2022] Open
Abstract
β2-Spectrin (β2SP/SPTBN1, gene SPTBN1) is a key TGF-β/SMAD3/4 adaptor and transcriptional cofactor that regulates TGF-β signaling and can contribute to liver cancer development. Here we report that cells deficient in β2-Spectrin (β2SP) are moderately sensitive to ionizing radiation (IR) and extremely sensitive to agents that cause interstrand cross-links (ICLs) or replication stress. In response to treatment with IR or ICL agents (formaldehyde, cisplatin, camptothecin, mitomycin), β2SP deficient cells displayed a higher frequency of cells with delayed γ-H2AX removal and a higher frequency of residual chromosome aberrations. Following hydroxyurea (HU)-induced replication stress, β2SP-deficient cells displayed delayed disappearance of γ-H2AX foci along with defective repair factor recruitment (MRE11, CtIP, RAD51, RPA, and FANCD2) as well as defective restart of stalled replication forks. Repair factor recruitment is a prerequisite for initiation of DNA damage repair by the homologous recombination (HR) pathway, which was also defective in β2SP deficient cells. We propose that β2SP is required for maintaining genomic stability following replication fork stalling, whether induced by either ICL damage or replicative stress, by facilitating fork regression as well as DNA damage repair by homologous recombination.
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Affiliation(s)
- Nobuo Horikoshi
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Department of Radiation Oncology, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Raj K Pandita
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Department of Radiation Oncology, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Kalpana Mujoo
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Shashank Hambarde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Dharmendra Sharma
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Abid R Mattoo
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Sharmistha Chakraborty
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Department of Radiation Oncology, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Vijaya Charaka
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Clayton R Hunt
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Department of Radiation Oncology, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Tej K Pandita
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Department of Radiation Oncology, University of Texas Southwestern Medical School, Dallas, TX, USA
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8
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Tanaka T, Goto K, Iino M. Sec8 modulates TGF-β induced EMT by controlling N-cadherin via regulation of Smad3/4. Cell Signal 2017; 29:115-126. [DOI: 10.1016/j.cellsig.2016.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/13/2016] [Accepted: 10/16/2016] [Indexed: 10/20/2022]
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9
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Tanaka T, Goto K, Iino M. Diverse Functions and Signal Transduction of the Exocyst Complex in Tumor Cells. J Cell Physiol 2016; 232:939-957. [DOI: 10.1002/jcp.25619] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/23/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Toshiaki Tanaka
- Department of Anatomy and Cell Biology; School of Medicine; Yamagata University; Yamagata Japan
- Department of Dentistry, Oral and Maxillofacial Surgery; Plastic and Reconstructive Surgery; School of Medicine; Yamagata University; Yamagata Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology; School of Medicine; Yamagata University; Yamagata Japan
| | - Mitsuyoshi Iino
- Department of Dentistry, Oral and Maxillofacial Surgery; Plastic and Reconstructive Surgery; School of Medicine; Yamagata University; Yamagata Japan
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10
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Inamdar SM, Hsu SC, Yeaman C. Probing Functional Changes in Exocyst Configuration with Monoclonal Antibodies. Front Cell Dev Biol 2016; 4:51. [PMID: 27376061 PMCID: PMC4891948 DOI: 10.3389/fcell.2016.00051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/10/2016] [Indexed: 01/19/2023] Open
Abstract
Spatial regulation of exocytosis relies on the exocyst, a hetero-octameric protein complex that tethers vesicles to fusion sites at the plasma membrane. Nevertheless, our understanding of mechanisms regulating exocyst assembly/disassembly, localization, and function are incomplete. Here, we have exploited a panel of anti-Sec6 monoclonal antibodies (mAbs) to probe possible configurational changes accompanying transitions in exocyst function in epithelial MDCK cells. Sec6 is quantitatively associated with Sec8 in high molecular weight complexes, as shown by gel filtration and co-immunoprecipitation studies. We mapped epitopes recognized by more than 20 distinct mAbs to one of six Sec6 segments. Surprisingly, mAbs that bound epitopes in each segment labeled distinct subcellular structures. In general, antibodies to epitopes in N-terminal domains labeled Sec6 in either cytosolic or nuclear pools, whereas those that bound epitopes in C-terminal domains labeled membrane-associated Sec6. In this latter group, we identified antibodies that labeled distinct Sec6 populations at the apical junctional complex, desmosomes, endoplasmic reticulum and vimentin-type intermediate filaments. That each antibody was specific was verified by both Sec6 RNAi and competition with fusion proteins containing each domain. Comparison of non-polarized and polarized cells revealed that many Sec6 epitopes either redistribute or become concealed during epithelial polarization. Transitions in exocyst configurations may be regulated in part by the actions of Ral GTPases, because the exposure of Sec6 C-terminal domain epitopes at the plasma membrane is significantly reduced upon RalA RNAi. To determine whether spatio-temporal changes in epitope accessibility was correlated with differential stability of interactions between Sec6 and other exocyst subunits, we quantified relative amounts of each subunit that co-immunoprecipitated with Sec6 when antibodies to N-terminal or C-terminal epitopes were used. Antibodies to Sec6NT co-precipitated substantially more Sec5, -10, -15, Exo70 and -84 than did those to Sec6CT. In contrast, antibodies to Sec6CT co-precipitated more Sec3 and Sec8 than did those to Sec6NT. These results are consistent with a model in which exocyst activation during periods of rapid membrane expansion is accompanied by molecular rearrangements within the holocomplex or association with accessory proteins, which expose the Sec6 C-terminal domain when the complex is membrane-bound and conceal it when the complex is cytoplasmic.
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Affiliation(s)
- Shivangi M Inamdar
- Molecular and Cellular Biology Program, University of IowaIowa City, IA, USA; Department of Anatomy and Cell Biology, University of IowaIowa City, IA, USA
| | - Shu-Chan Hsu
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Charles Yeaman
- Molecular and Cellular Biology Program, University of IowaIowa City, IA, USA; Department of Anatomy and Cell Biology, University of IowaIowa City, IA, USA
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Martin-Urdiroz M, Deeks MJ, Horton CG, Dawe HR, Jourdain I. The Exocyst Complex in Health and Disease. Front Cell Dev Biol 2016; 4:24. [PMID: 27148529 PMCID: PMC4828438 DOI: 10.3389/fcell.2016.00024] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/11/2016] [Indexed: 01/23/2023] Open
Abstract
Exocytosis involves the fusion of intracellular secretory vesicles with the plasma membrane, thereby delivering integral membrane proteins to the cell surface and releasing material into the extracellular space. Importantly, exocytosis also provides a source of lipid moieties for membrane extension. The tethering of the secretory vesicle before docking and fusion with the plasma membrane is mediated by the exocyst complex, an evolutionary conserved octameric complex of proteins. Recent findings indicate that the exocyst complex also takes part in other intra-cellular processes besides secretion. These various functions seem to converge toward defining a direction of membrane growth in a range of systems from fungi to plants and from neurons to cilia. In this review we summarize the current knowledge of exocyst function in cell polarity, signaling and cell-cell communication and discuss implications for plant and animal health and disease.
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Affiliation(s)
| | - Michael J Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Connor G Horton
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Isabelle Jourdain
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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Sec6/8 regulates Bcl-2 and Mcl-1, but not Bcl-xl, in malignant peripheral nerve sheath tumor cells. Apoptosis 2016; 21:594-608. [DOI: 10.1007/s10495-016-1230-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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