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Shang J, Mu G, Qi Y, Zhang X, Shen W, Xie Y, Ge M, He Y, Qiao F, Qiu QS. NHX5/NHX6/SPY22 complex regulates BRI1 and brassinosteroid signaling in Arabidopsis. JOURNAL OF PLANT PHYSIOLOGY 2024; 302:154318. [PMID: 39059150 DOI: 10.1016/j.jplph.2024.154318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 07/21/2024] [Accepted: 07/22/2024] [Indexed: 07/28/2024]
Abstract
NHX5 and NHX6, Arabidopsis endosomal antiporters, play a vital role in facilitating ion and pH homeostasis in endosomal compartments. Studies have found that NHX5 and NHX6 are essential for protein trafficking, auxin homeostasis, and plant growth and development. Here, we report the role of NHX5 and NHX6 in brassinosteroid (BR) signaling. We found that hypocotyl growth was enhanced in nhx5 nhx6 under epibrassinolide (eBR) treatment. nhx5 nhx6 bri1 was insensitive to eBR treatment, indicating that NHX5 and NHX6 are downstream of the BRI1 receptor in BR signaling. Moreover, confocal observation with both hypocotyls and root tips showed that BRI1-YFP localization in the plasma membrane (PM) was reduced in nhx5 nhx6. Interestingly, brefeldin A (BFA) treatment showed that formation of the BFA bodies containing BRI1 and their disassembling were disrupted in nhx5 nhx6. Further genetic analysis showed that NHX5/NHX6 and SYP22 may act coordinately in BR signaling. NHX5 and NHX6 may regulate SYP22 function by modulating cellular K+ and pH homeostasis. Importantly, NHX5 and NHX6 colocalize and interact with SYP22, but do not interact with BRI1. In summary, our findings indicate that NHX5/NHX6/SYP22 complex is essential for the regulation of BRI1 recycling and PM localization. The H+-leak facilitated by NHX5 and NHX6 offers a means of controlling BR signaling in plants.
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Affiliation(s)
- Jun Shang
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China
| | - Guoxiu Mu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Yuting Qi
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China; College of Life Science and Technology, Tarim University, Alar, 843300, China
| | - Wei Shen
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Yujie Xie
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Mingrui Ge
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Yu He
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Feng Qiao
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China.
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Shrestha B, Yang S, Griffith L, Ma J, Wang F, Liu H, Zhao Q, Du Y, Zhang J, Chang J, Guo JT. Discovery of hepatitis B virus subviral particle biogenesis inhibitors from a bioactive compound library. Antiviral Res 2024; 228:105955. [PMID: 38964614 DOI: 10.1016/j.antiviral.2024.105955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 06/30/2024] [Accepted: 07/01/2024] [Indexed: 07/06/2024]
Abstract
High levels of hepatitis B virus (HBV) surface antigen (HBsAg) in the blood of chronic HBV carriers are considered to drive the exhaustion of antigen-specific T and B lymphocytes and thus responsible for the persistence of infection. Accordingly, therapeutic elimination of HBsAg may facilitate the activation of adaptive antiviral immune responses against HBV and achieve a functional cure of chronic hepatitis B. We discovered recently that an amphipathic alpha helix spanning W156 to R169 of HBV small envelope (S) protein plays an essential role in the morphogenesis of subviral particles (SVPs) and metabolism of S protein. We thus hypothesized that pharmacological disruption of SVP morphogenesis may induce intracellular degradation of S protein and reduce HBsAg secretion. To identify inhibitors of SVP biogenesis, we screened 4417 bioactive compounds with a HepG2-derived cell line expressing HBV S protein and efficiently secreting small spherical SVPs. The screen identified 24 compounds that reduced intracellular SVPs and secreted HBsAg in a concentration-dependent manner. However, 18 of those compounds inhibited the secretion of HBsAg and HBeAg in HBV replicon transfected HepG2 cells at similar efficiency, suggesting each of those compounds may disrupt a common cellular function required for the synthesis and/or secretion of these viral proteins. Interestingly, lycorine more efficiently inhibited the secretion of HBsAg in HepG2 cells transfected with HBV replicons, HepG2.2.15 cells and HBV infected - HepG2 cells expressing sodium taurocholate cotransporting polypeptide (NTCP). The structure activity relationship and antiviral mechanism of lycorine against HBV have been determined.
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Affiliation(s)
| | - Sisi Yang
- Baruch S. Blumberg Institute, Doylestown, PA, USA; Department of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | | | - Julia Ma
- Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Fuxuan Wang
- Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Hui Liu
- Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Qiong Zhao
- Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Yanming Du
- Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Jiming Zhang
- Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | | | - Ju-Tao Guo
- Baruch S. Blumberg Institute, Doylestown, PA, USA.
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3
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Zhang ZH, Sun LL, Fu BQ, Deng J, Jia CL, Miao MX, Yang F, Cao YB, Yan TH. Aneuploidy underlies brefeldin A-induced antifungal drug resistance in Cryptococcus neoformans. Front Cell Infect Microbiol 2024; 14:1397724. [PMID: 38966251 PMCID: PMC11222406 DOI: 10.3389/fcimb.2024.1397724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/17/2024] [Indexed: 07/06/2024] Open
Abstract
Cryptococcus neoformans is at the top of the list of "most wanted" human pathogens. Only three classes of antifungal drugs are available for the treatment of cryptococcosis. Studies on antifungal resistance mechanisms are limited to the investigation of how a particular antifungal drug induces resistance to a particular drug, and the impact of stresses other than antifungals on the development of antifungal resistance and even cross-resistance is largely unexplored. The endoplasmic reticulum (ER) is a ubiquitous subcellular organelle of eukaryotic cells. Brefeldin A (BFA) is a widely used chemical inducer of ER stress. Here, we found that both weak and strong selection by BFA caused aneuploidy formation in C. neoformans, mainly disomy of chromosome 1, chromosome 3, and chromosome 7. Disomy of chromosome 1 conferred cross-resistance to two classes of antifungal drugs: fluconazole and 5-flucytosine, as well as hypersensitivity to amphotericin B. However, drug resistance was unstable, due to the intrinsic instability of aneuploidy. We found overexpression of AFR1 on Chr1 and GEA2 on Chr3 phenocopied BFA resistance conferred by chromosome disomy. Overexpression of AFR1 also caused resistance to fluconazole and hypersensitivity to amphotericin B. Furthermore, a strain with a deletion of AFR1 failed to form chromosome 1 disomy upon BFA treatment. Transcriptome analysis indicated that chromosome 1 disomy simultaneously upregulated AFR1, ERG11, and other efflux and ERG genes. Thus, we posit that BFA has the potential to drive the rapid development of drug resistance and even cross-resistance in C. neoformans, with genome plasticity as the accomplice.
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Affiliation(s)
- Zhi-hui Zhang
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Liu-liu Sun
- Department of Pharmacy, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bu-qing Fu
- Laboratory Department, Jiangsu Province Hospital of Chinese Medicine, Nanjing, China
| | - Jie Deng
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Cheng-lin Jia
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ming-xing Miao
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Feng Yang
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Department of Pharmacy, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yong-bing Cao
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Tian-hua Yan
- Department of Physiology and Pharmacology, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
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4
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Natsume M, Niwa M, Ichikawa S, Okamoto T, Tsutsui H, Usukura D, Murata T, Abe R, Shimonaka M, Nishida T, Shiina I, Obata Y. Brefeldin A and M-COPA block the export of RTKs from the endoplasmic reticulum via simultaneous inactivation of ARF1, ARF4, and ARF5. J Biol Chem 2024; 300:107327. [PMID: 38679330 PMCID: PMC11127164 DOI: 10.1016/j.jbc.2024.107327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/20/2024] [Accepted: 04/17/2024] [Indexed: 05/01/2024] Open
Abstract
Normal receptor tyrosine kinases (RTKs) need to reach the plasma membrane (PM) for ligand-induced activation, whereas its cancer-causing mutants can be activated before reaching the PM in organelles, such as the Golgi/trans-Golgi network (TGN). Inhibitors of protein export from the endoplasmic reticulum (ER), such as brefeldin A (BFA) and 2-methylcoprophilinamide (M-COPA), can suppress the activation of mutant RTKs in cancer cells, suggesting that RTK mutants cannot initiate signaling in the ER. BFA and M-COPA block the function of ADP-ribosylation factors (ARFs) that play a crucial role in ER-Golgi protein trafficking. However, among ARF family proteins, the specific ARFs inhibited by BFA or M-COPA, that is, the ARFs involved in RTKs transport from the ER, remain unclear. In this study, we showed that M-COPA blocked the export of not only KIT but also PDGFRA/EGFR/MET RTKs from the ER. ER-retained RTKs could not fully transduce anti-apoptotic signals, thereby leading to cancer cell apoptosis. Moreover, a single knockdown of ARF1, ARF3, ARF4, ARF5, or ARF6 could not block ER export of RTKs, indicating that BFA/M-COPA treatment cannot be mimicked by the knockdown of only one ARF member. Interestingly, simultaneous transfection of ARF1, ARF4, and ARF5 siRNAs mirrored the effect of BFA/M-COPA treatment. Consistent with these results, in vitro pulldown assays showed that BFA/M-COPA blocked the function of ARF1, ARF4, and ARF5. Taken together, these results suggest that BFA/M-COPA targets at least ARF1, ARF4, and ARF5; in other words, RTKs require the simultaneous activation of ARF1, ARF4, and ARF5 for their ER export.
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Affiliation(s)
- Miyuki Natsume
- Laboratory of Intracellular Traffic & Oncology, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan; Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Mariko Niwa
- Laboratory of Intracellular Traffic & Oncology, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan; Faculty of Science, Department of Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Sho Ichikawa
- Laboratory of Intracellular Traffic & Oncology, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan; Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Takuma Okamoto
- Laboratory of Intracellular Traffic & Oncology, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan; Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Hisazumi Tsutsui
- Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Daiki Usukura
- Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Takatsugu Murata
- Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Ryo Abe
- Tokyo University of Science, Noda, Chiba, Japan
| | - Motoyuki Shimonaka
- Faculty of Science, Department of Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Toshirou Nishida
- National Cancer Center Hospital, Chuo-ku, Tokyo, Japan; Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka, Japan
| | - Isamu Shiina
- Faculty of Science, Department of Applied Chemistry, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Yuuki Obata
- Laboratory of Intracellular Traffic & Oncology, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan.
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5
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Jermusek FA, Webb LJ. Electrostatic Impact of Brefeldin A on Thiocyanate Probes Surrounding the Interface of Arf1-BFA-ARNO4M, a Protein-Drug-Protein Complex. Biochemistry 2024; 63:27-41. [PMID: 38078826 DOI: 10.1021/acs.biochem.3c00366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Protein-protein interactions regulate many cellular processes, making them ideal drug candidates. Design of such drugs, however, is hindered by a lack of understanding of the factors that contribute to the interaction specificity. Specific protein-protein complexes possess both structural and electrostatic complementarity, and while structural complementarity of protein complexes has been extensively investigated, fundamental understanding of the complicated networks of electrostatic interactions at these interfaces is lacking, thus hindering the rational design of orthosterically binding small molecules. To better understand the electrostatic interactions at protein interfaces and how a small molecule could contribute to and fit within that environment, we used a model protein-drug-protein system, Arf1-BFA-ARNO4M, to investigate how small molecule brefeldin A (BFA) perturbs the Arf1-ARNO4M interface. By using nitrile probe labeled Arf1 sites and measuring vibrational Stark effects as well as temperature dependent infrared shifts, we measured changes in the electric field and hydrogen bonding at this interface upon BFA binding. At all five probe locations of Arf1, we found that the vibrational shifts resulting from BFA binding corroborate trends found in Poisson-Boltzmann calculations of surface potentials of Arf1-ARNO4M and Arf1-BFA-ARNO4M, where BFA contributes negative electrostatic potential to the protein interface. The data also corroborate previous hypotheses about the mechanism of interfacial binding and confirm that alternating patches of hydrophobic and polar interactions lead to BFA binding specificity. These findings demonstrate the impact of BFA on this protein-protein interface and have implications for the design of other interfacial drug candidates.
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Affiliation(s)
- Frank A Jermusek
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Lauren J Webb
- Department of Chemistry and Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, Texas 78712, United States
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6
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Gruber L, Jobst M, Kiss E, Karasová M, Englinger B, Berger W, Del Favero G. Intracellular remodeling associated with endoplasmic reticulum stress modifies biomechanical compliance of bladder cells. Cell Commun Signal 2023; 21:307. [PMID: 37904178 PMCID: PMC10614373 DOI: 10.1186/s12964-023-01295-x] [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: 06/16/2023] [Accepted: 08/23/2023] [Indexed: 11/01/2023] Open
Abstract
Bladder cells face a challenging biophysical environment: mechanical cues originating from urine flow and regular contraction to enable the filling voiding of the organ. To ensure functional adaption, bladder cells rely on high biomechanical compliance, nevertheless aging or chronic pathological conditions can modify this plasticity. Obviously the cytoskeletal network plays an essential role, however the contribution of other, closely entangled, intracellular organelles is currently underappreciated. The endoplasmic reticulum (ER) lies at a crucial crossroads, connected to both nucleus and cytoskeleton. Yet, its role in the maintenance of cell mechanical stability is less investigated. To start exploring these aspects, T24 bladder cancer cells were treated with the ER stress inducers brefeldin A (10-40nM BFA, 24 h) and thapsigargin (0.1-100nM TG, 24 h). Without impairment of cell motility and viability, BFA and TG triggered a significant subcellular redistribution of the ER; this was associated with a rearrangement of actin cytoskeleton. Additional inhibition of actin polymerization with cytochalasin D (100nM CytD) contributed to the spread of the ER toward cell periphery, and was accompanied by an increase of cellular stiffness (Young´s modulus) in the cytoplasmic compartment. Shrinking of the ER toward the nucleus (100nM TG, 2 h) was related to an increased stiffness in the nuclear and perinuclear areas. A similar short-term response profile was observed also in normal human primary bladder fibroblasts. In sum, the ER and its subcellular rearrangement seem to contribute to the mechanical properties of bladder cells opening new perspectives in the study of the related stress signaling cascades. Video Abstract.
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Affiliation(s)
- Livia Gruber
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
| | - Maximilian Jobst
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
- University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, Vienna, 1090, Austria
| | - Endre Kiss
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
| | - Martina Karasová
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
| | - Bernhard Englinger
- Department of Urology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, 1090, Austria
- Center for Cancer Research and Comprehensive Cancer Center, Medical University Vienna, Vienna, 1090, Austria
| | - Walter Berger
- Center for Cancer Research and Comprehensive Cancer Center, Medical University Vienna, Vienna, 1090, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria.
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria.
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7
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Viktorova EG, Gabaglio S, Moghimi S, Zimina A, Wynn BG, Sztul E, Belov GA. The development of resistance to an inhibitor of a cellular protein reveals a critical interaction between the enterovirus protein 2C and a small GTPase Arf1. PLoS Pathog 2023; 19:e1011673. [PMID: 37721955 PMCID: PMC10538752 DOI: 10.1371/journal.ppat.1011673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/28/2023] [Accepted: 09/08/2023] [Indexed: 09/20/2023] Open
Abstract
The cellular protein GBF1, an activator of Arf GTPases (ArfGEF: Arf guanine nucleotide exchange factor), is recruited to the replication organelles of enteroviruses through interaction with the viral protein 3A, and its ArfGEF activity is required for viral replication, however how GBF1-dependent Arf activation supports the infection remains enigmatic. Here, we investigated the development of resistance of poliovirus, a prototype enterovirus, to increasing concentrations of brefeldin A (BFA), an inhibitor of GBF1. High level of resistance required a gradual accumulation of multiple mutations in the viral protein 2C. The 2C mutations conferred BFA resistance even in the context of a 3A mutant previously shown to be defective in the recruitment of GBF1 to replication organelles, and in cells depleted of GBF1, suggesting a GBF1-independent replication mechanism. Still, activated Arfs accumulated on the replication organelles of this mutant even in the presence of BFA, its replication was inhibited by a pan-ArfGEF inhibitor LM11, and the BFA-resistant phenotype was compromised in Arf1-knockout cells. Importantly, the mutations strongly increased the interaction of 2C with the activated form of Arf1. Analysis of other enteroviruses revealed a particularly strong interaction of 2C of human rhinovirus 1A with activated Arf1. Accordingly, the replication of this virus was significantly less sensitive to BFA than that of poliovirus. Thus, our data demonstrate that enterovirus 2Cs may behave like Arf1 effector proteins and that GBF1 but not Arf activation can be dispensable for enterovirus replication. These findings have important implications for the development of host-targeted anti-viral therapeutics.
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Affiliation(s)
- Ekaterina G. Viktorova
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Samuel Gabaglio
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Seyedehmahsa Moghimi
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Anna Zimina
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Bridge G. Wynn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham; Birmingham, Alabama, United States of America
| | - Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham; Birmingham, Alabama, United States of America
| | - George A. Belov
- Department of Veterinary Medicine and Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
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8
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Babazadeh R, Schneider KL, Fischbach A, Hao X, Liu B, Nystrom T. The yeast guanine nucleotide exchange factor Sec7 is a bottleneck in spatial protein quality control and detoxifies neurological disease proteins. Sci Rep 2023; 13:14068. [PMID: 37640758 PMCID: PMC10462735 DOI: 10.1038/s41598-023-41188-0] [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: 01/30/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023] Open
Abstract
ER-to-Golgi trafficking partakes in the sorting of misfolded cytoplasmic proteins to reduce their cytological toxicity. We show here that yeast Sec7, a protein involved in proliferation of the Golgi, is part of this pathway and participates in an Hsp70-dependent formation of insoluble protein deposits (IPOD). Sec7 associates with the disaggregase Hsp104 during a mild heat shock and increases the rate of Hsp104 diffusion in an Hsp70-dependent manner when overproduced. Sec7 overproduction increased formation of IPODs from smaller aggregates and mitigated the toxicity of Huntingtin exon-1 upon heat stress while Sec7 depletion increased sensitivity to aẞ42 of the Alzheimer's disease and α-synuclein of the Parkinson's disease, suggesting a role of Sec7 in mitigating proteotoxicity.
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Affiliation(s)
- Roja Babazadeh
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Kara L Schneider
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Arthur Fischbach
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Xinxin Hao
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90, Gothenburg, Sweden
| | - Thomas Nystrom
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden.
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9
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Kasberg W, Luong P, Hanna MG, Minushkin K, Tsao A, Shankar R, Block S, Audhya A. The Sar1 GTPase is dispensable for COPII-dependent cargo export from the ER. Cell Rep 2023; 42:112635. [PMID: 37300835 PMCID: PMC10592460 DOI: 10.1016/j.celrep.2023.112635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 04/21/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Coat protein complex II (COPII) plays an integral role in the packaging of secretory cargoes within membrane-enclosed transport carriers that leave the endoplasmic reticulum (ER) from discrete subdomains. Lipid bilayer remodeling necessary for this process is driven initially by membrane penetration mediated by the Sar1 GTPase and further stabilized by assembly of a multilayered complex of several COPII proteins. However, the relative contributions of these distinct factors to transport carrier formation and protein trafficking remain unclear. Here, we demonstrate that anterograde cargo transport from the ER continues in the absence of Sar1, although the efficiency of this process is dramatically reduced. Specifically, secretory cargoes are retained nearly five times longer at ER subdomains when Sar1 is depleted, but they ultimately remain capable of being translocated to the perinuclear region of cells. Taken together, our findings highlight alternative mechanisms by which COPII promotes transport carrier biogenesis.
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Affiliation(s)
- William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Peter Luong
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Michael G Hanna
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Kayla Minushkin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Annabelle Tsao
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Samuel Block
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA.
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10
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B.R. R, Shah N, Joshi P, Madhusudan MS, Balasubramanian N. Kinetics of Arf1 inactivation regulates Golgi organisation and function in non-adherent fibroblasts. Biol Open 2023; 12:bio059669. [PMID: 36946871 PMCID: PMC10187640 DOI: 10.1242/bio.059669] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 03/13/2023] [Indexed: 03/23/2023] Open
Abstract
Arf1 belongs to the Arf family of small GTPases that localise at the Golgi and plasma membrane. Active Arf1 plays a crucial role in regulating Golgi organisation and function. In mouse fibroblasts, loss of adhesion triggers a consistent drop (∼50%) in Arf1 activation that causes the Golgi to disorganise but not fragment. In suspended cells, the trans-Golgi (GalTase) disperses more prominently than cis-Golgi (Man II), accompanied by increased active Arf1 (detected using GFP-ABD: ARHGAP10 Arf1 binding domain) associated with the cis-Golgi compartment. Re-adhesion restores Arf1 activation at the trans-Golgi as it reorganises. Arf1 activation at the Golgi is regulated by Arf1 Guanine nucleotide exchange factors (GEFs), GBF1, and BIG1/2. In non-adherent fibroblasts, the cis-medial Golgi provides a unique setting to test and understand the role GEF-mediated Arf1 activation has in regulating Golgi organisation. Labelled with Man II-GFP, non-adherent fibroblasts treated with increasing concentrations of Brefeldin-A (BFA) (which inhibits BIG1/2 and GBF1) or Golgicide A (GCA) (which inhibits GBF1 only) comparably decrease active Arf1 levels. They, however, cause a concentration-dependent increase in cis-medial Golgi fragmentation and fusion with the endoplasmic reticulum (ER). Using selected BFA and GCA concentrations, we find a change in the kinetics of Arf1 inactivation could mediate this by regulating cis-medial Golgi localisation of GBF1. On loss of adhesion, a ∼50% drop in Arf1 activation over 120 min causes the Golgi to disorganise. The kinetics of this drop, when altered by BFA or GCA treatment causes a similar decline in Arf1 activation but over 10 min. This causes the Golgi to now fragment which affects cell surface glycosylation and re-adherent cell spreading. Using non-adherent fibroblasts this study reveals the kinetics of Arf1 inactivation, with active Arf1 levels, to be vital for Golgi organisation and function.
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Affiliation(s)
- Rajeshwari B.R.
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
| | - Nikita Shah
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
| | - Prachi Joshi
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
| | - M. S. Madhusudan
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
| | - Nagaraj Balasubramanian
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
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11
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Hsiao AS, Huang JY. Bioimaging tools move plant physiology studies forward. FRONTIERS IN PLANT SCIENCE 2022; 13:976627. [PMID: 36204075 PMCID: PMC9530904 DOI: 10.3389/fpls.2022.976627] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Affiliation(s)
- An-Shan Hsiao
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Ji-Ying Huang
- Cell Biology Core Lab, Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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12
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Domostegui A, Nieto-Barrado L, Perez-Lopez C, Mayor-Ruiz C. Chasing molecular glue degraders: screening approaches. Chem Soc Rev 2022; 51:5498-5517. [PMID: 35723413 DOI: 10.1039/d2cs00197g] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Protein-protein interactions (PPIs) govern all biological processes. Some small molecules modulate PPIs through induced protein proximity. In particular, molecular glue degraders are monovalent compounds that orchestrate interactions between a target protein and an E3 ubiquitin ligase, prompting the proteasomal degradation of the former. This and other pharmacological strategies of targeted protein degradation (e.g. proteolysis-targeting chimeras - PROTACs) overcome some limitations of traditional occupancy-based therapeutics. Here, we provide an overview of the "molecular glue" concept, with a special focus on natural and synthetic inducers of proximity to E3s. We then briefly highlight the serendipitous discoveries of some clinical and preclinical molecular glue degraders, and discuss the first examples of intentional discoveries. Specifically, we outline the different screening strategies reported in this rapidly evolving arena and our thoughts on future perspectives. By mastering the ability to influence PPIs, molecular glue degraders can induce the degradation of unligandable proteins, thus providing an exciting path forward to broaden the targetable proteome.
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Affiliation(s)
- Ana Domostegui
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Luis Nieto-Barrado
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Carles Perez-Lopez
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
| | - Cristina Mayor-Ruiz
- IRB Barcelona - Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain.
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13
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Husein D, Alamoudi A, Ohyama Y, Mochida H, Ritter B, Mochida Y. Identification of the C-terminal region in Amelogenesis Imperfecta causative protein WDR72 required for Golgi localization. Sci Rep 2022; 12:4640. [PMID: 35301423 PMCID: PMC8930991 DOI: 10.1038/s41598-022-08719-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 02/28/2022] [Indexed: 11/22/2022] Open
Abstract
Amelogenesis Imperfecta (AI) represents a group of hereditary conditions that manifest tooth enamel defects. Several causative mutations in the WDR72 gene have been identified and patients with WDR72 mutations have brown (or orange-brown) discolored enamel, rough enamel surface, early loss of enamel after tooth eruption, and severe attrition. Although the molecular function of WDR72 is not yet fully understood, a recent study suggested that WDR72 could be a facilitator of endocytic vesicle trafficking, which appears inconsistent with the previously reported cytoplasmic localization of WDR72. Therefore, the aims of our study were to investigate the tissues and cell lines in which WDR72 was expressed and to further determine the sub-cellular localization of WDR72. The expression of Wdr72 gene was investigated in mouse tissues and cell lines. Endogenous WDR72 protein was detected in the membranous fraction of ameloblast cell lines in addition to the cytosolic fraction. Sub-cellular localization studies supported our fractionation data, showing WDR72 at the Golgi apparatus, and to a lesser extent, in the cytoplasmic area. In contrast, a WDR72 AI mutant form that lacks its C-terminal region was exclusively detected in the cytoplasm. In addition, our studies identified a putative prenylation/CAAX motif within the last four amino acids of human WDR72 and generated a WDR72 variant, called CS mutant, in which the putative motif was ablated by a point mutation. Interestingly, mutation of the putative CAAX motif impaired WDR72 recruitment to the Golgi. Cell fractionation assays confirmed subcellular distribution of wild-type WDR72 in both cytosolic and membranous fractions, while the WDR72 AI mutant and CS mutant forms were predominantly detected in the cytosolic fraction. Our studies provide new insights into the subcellular localization of WDR72 and demonstrate a critical role for the C-terminal CAAX motif in regulating WDR72 recruitment to the Golgi. In accordance with structural modelling studies that classified WDR72 as a potential vesicle transport protein, our findings suggest a role for WDR72 in vesicular Golgi transport that may be key to understanding the underlying cause of AI.
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Affiliation(s)
- Dina Husein
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Ahmed Alamoudi
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
- Oral Biology Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Yoshio Ohyama
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Hanna Mochida
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Brigitte Ritter
- Department of Biochemistry, School of Medicine, Boston University, Boston, MA, USA
| | - Yoshiyuki Mochida
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, USA.
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Lawson CD, Hornigold K, Pan D, Niewczas I, Andrews S, Clark J, Welch HCE. Small-molecule inhibitors of P-Rex guanine-nucleotide exchange factors. Small GTPases 2022; 13:307-326. [PMID: 36342857 PMCID: PMC9645260 DOI: 10.1080/21541248.2022.2131313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
P-Rex1 and P-Rex2 are guanine-nucleotide exchange factors (GEFs) that activate Rac small GTPases in response to the stimulation of G protein-coupled receptors and phosphoinositide 3-kinase. P-Rex Rac-GEFs regulate the morphology, adhesion and migration of various cell types, as well as reactive oxygen species production and cell cycle progression. P-Rex Rac-GEFs also have pathogenic roles in the initiation, progression or metastasis of several types of cancer. With one exception, all P-Rex functions are known or assumed to be mediated through their catalytic Rac-GEF activity. Thus, inhibitors of P-Rex Rac-GEF activity would be valuable research tools. We have generated a panel of small-molecule P-Rex inhibitors that target the interface between the catalytic DH domain of P-Rex Rac-GEFs and Rac. Our best-characterized compound, P-Rex inhibitor 1 (PREX-in1), blocks the Rac-GEF activity of full-length P-Rex1 and P-Rex2, and of their isolated catalytic domains, in vitro at low-micromolar concentration, without affecting the activities of several other Rho-GEFs. PREX-in1 blocks the P-Rex1 dependent spreading of PDGF-stimulated endothelial cells and the production of reactive oxygen species in fMLP-stimulated mouse neutrophils. Structure-function analysis revealed critical structural elements of PREX-in1, allowing us to develop derivatives with increased efficacy, the best with an IC50 of 2 µM. In summary, we have developed PREX-in1 and derivative small-molecule compounds that will be useful laboratory research tools for the study of P-Rex function. These compounds may also be a good starting point for the future development of more sophisticated drug-like inhibitors aimed at targeting P-Rex Rac-GEFs in cancer.
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Affiliation(s)
- CD Lawson
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - K Hornigold
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - D Pan
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - I Niewczas
- Biological Chemistry Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - S Andrews
- Bioinformatics Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - J Clark
- Biological Chemistry Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - HCE Welch
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK,CONTACT HCE Welch Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3ATUK
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15
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Unconventional p97/VCP-Mediated Endoplasmic Reticulum-to-Endosome Trafficking of a Retroviral Protein. J Virol 2021; 95:e0053121. [PMID: 33952644 DOI: 10.1128/jvi.00531-21] [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] [Indexed: 12/26/2022] Open
Abstract
Mouse mammary tumor virus (MMTV) encodes a Rem precursor protein that specifies both regulatory and accessory functions. Rem is cleaved at the endoplasmic reticulum (ER) membrane into a functional N-terminal signal peptide (SP) and the C terminus (Rem-CT). Rem-CT lacks a membrane-spanning domain and a known ER retention signal, and yet it was not detectably secreted into cell supernatants. Inhibition of intracellular trafficking by the drug brefeldin A (BFA), which interferes with the ER-to-Golgi secretory pathway, resulted in dramatically reduced intracellular Rem-CT levels that were not rescued by proteasomal or lysosomal inhibitors. A Rem mutant lacking glycosylation was cleaved into SP and Rem-CT but was insensitive to BFA, suggesting that unglycosylated Rem-CT does not reach this BFA-dependent compartment. Treatment with endoglycosidase H indicated that Rem-CT does not traffic through the Golgi apparatus. Analysis of wild-type Rem-CT and its glycosylation mutant by confocal microscopy revealed that both were primarily localized to the ER lumen. A small fraction of wild-type Rem-CT, but not the unglycosylated mutant, was colocalized with Rab5-positive (Rab5+) early endosomes. The expression of a dominant-negative (DN) form of ADP ribosylation factor 1 (Arf1) (containing a mutation of threonine to asparagine at position 31 [T31N]) mimicked the effects of BFA by reducing Rem-CT levels and increased Rem-CT association with early and late endosomes. Inhibition of the AAA ATPase p97/VCP rescued Rem-CT in the presence of BFA or DN Arf1 and prevented localization to Rab5+ endosomes. Thus, Rem-CT uses an unconventional p97-mediated scheme for trafficking to early endosomes. IMPORTANCE Mouse mammary tumor virus is a complex retrovirus that encodes a regulatory/accessory protein, Rem. Rem is a precursor protein that is processed at the endoplasmic reticulum (ER) membrane by signal peptidase. The N-terminal SP uses the p97/VCP ATPase to elude ER-associated degradation to traffic to the nucleus and serve a human immunodeficiency virus Rev-like function. In contrast, the function of the C-terminal glycosylated cleavage product (Rem-CT) is unknown. Since localization is critical for protein function, we used mutants, inhibitors, and confocal microscopy to localize Rem-CT. Surprisingly, Rem-CT, which lacks a transmembrane domain or an ER retention signal, was detected primarily within the ER and required glycosylation and the p97 ATPase for early endosome trafficking without passage through the Golgi apparatus. Thus, Rem-CT uses a novel intracellular trafficking pathway, potentially impacting host antiviral immunity.
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16
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You KS, Yi YW, Cho J, Park JS, Seong YS. Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer. Pharmaceuticals (Basel) 2021; 14:589. [PMID: 34207383 PMCID: PMC8233743 DOI: 10.3390/ph14060589] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/07/2021] [Accepted: 06/14/2021] [Indexed: 12/13/2022] Open
Abstract
Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.
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Affiliation(s)
- Kyu Sic You
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan 31116, Chungcheongnam-do, Korea;
- Graduate School of Convergence Medical Science, Dankook University, Cheonan 3116, Chungcheongnam-do, Korea
| | - Yong Weon Yi
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Chungcheongnam-do, Korea; (Y.W.Y.); (J.C.)
| | - Jeonghee Cho
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Chungcheongnam-do, Korea; (Y.W.Y.); (J.C.)
| | - Jeong-Soo Park
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan 31116, Chungcheongnam-do, Korea;
| | - Yeon-Sun Seong
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan 31116, Chungcheongnam-do, Korea;
- Graduate School of Convergence Medical Science, Dankook University, Cheonan 3116, Chungcheongnam-do, Korea
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Chungcheongnam-do, Korea; (Y.W.Y.); (J.C.)
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17
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Highland CM, Fromme JC. Arf1 directly recruits the Pik1-Frq1 PI4K complex to regulate the final stages of Golgi maturation. Mol Biol Cell 2021; 32:1064-1080. [PMID: 33788598 PMCID: PMC8101487 DOI: 10.1091/mbc.e21-02-0069] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
Proper Golgi complex function depends on the activity of Arf1, a GTPase whose effectors assemble and transport outgoing vesicles. Phosphatidylinositol 4-phosphate (PI4P) generated at the Golgi by the conserved PI 4-kinase Pik1 (PI4KIIIβ) is also essential for Golgi function, although its precise roles in vesicle formation are less clear. Arf1 has been reported to regulate PI4P production, but whether Pik1 is a direct Arf1 effector is not established. Using a combination of live-cell time-lapse imaging analyses, acute PI4P depletion experiments, and in vitro protein-protein interaction assays on Golgi-mimetic membranes, we present evidence for a model in which Arf1 initiates the final stages of Golgi maturation by tightly controlling PI4P production through direct recruitment of the Pik1-Frq1 PI4-kinase complex. This PI4P serves as a critical signal for AP-1 and secretory vesicle formation, the final events at maturing Golgi compartments. This work therefore establishes the regulatory and temporal context surrounding Golgi PI4P production and its precise roles in Golgi maturation.
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Affiliation(s)
- Carolyn M. Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J. Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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18
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A putative amphipathic alpha helix in hepatitis B virus small envelope protein plays a critical role in the morphogenesis of subviral particles. J Virol 2021; 95:JVI.02399-20. [PMID: 33536177 PMCID: PMC8103704 DOI: 10.1128/jvi.02399-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hepatitis B virus (HBV) small (S) envelope protein has the intrinsic ability to direct the formation of small spherical subviral particles (SVPs) in eukaryotic cells. However, the molecular mechanism underlying the morphogenesis of SVPs from the monomeric S protein initially synthesized at the endoplasmic reticulum (ER) membrane remains largely elusive. Structure prediction and extensive mutagenesis analysis suggested that the amino acid residues spanning W156 to R169 of S protein form an amphipathic alpha helix and play essential roles in SVP production and S protein metabolic stability. Further biochemical analyses showed that the putative amphipathic alpha helix was not required for the disulfide-linked S protein oligomerization, but was essential for SVP morphogenesis. Pharmacological disruption of vesicle trafficking between the ER and Golgi complex in SVP producing cells supported the hypothesis that S protein-directed SVP morphogenesis takes place at the ER-Golgi intermediate compartment (ERGIC). Moreover, it was demonstrated that S protein is degraded in hepatocytes via a 20S proteasome-dependent, but ubiquitination-independent non-classic ER-associated degradation (ERAD) pathway. Taken together, the results reported herein favor a model in which the amphipathic alpha helix at the antigenic loop of S protein attaches to the lumen leaflet to facilitate SVP budding from the ERGIC compartment, whereas the failure of budding process may result in S protein degradation by 20S proteasome in an ubiquitination-independent manner.Importance Subviral particles are the predominant viral product produced by HBV-infected hepatocytes. Their levels exceed the virion particles by 10,000 to 100,000-fold in the blood of HBV infected individuals. The high levels of SVPs, or HBV surface antigen (HBsAg), in the circulation induces immune tolerance and contributes to the establishment of persistent HBV infection. The loss of HBsAg, often accompanied by appearance of anti-HBs antibodies, is the hallmark of durable immune control of HBV infection. Therapeutic induction of HBsAg loss is, therefore, considered to be essential for the restoration of host antiviral immune response and functional cure of chronic hepatitis B. Our findings on the mechanism of SVP morphogenesis and S protein metabolism will facilitate the rational discovery and development of antiviral drugs to achieve this therapeutic goal.
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Meneghetti MCZ, Deboni P, Palomino CMV, Braga LP, Cavalheiro RP, Viana GM, Yates EA, Nader HB, Lima MA. ER-Golgi dynamics of HS-modifying enzymes via vesicular trafficking is a critical prerequisite for the delineation of HS biosynthesis. Carbohydr Polym 2021; 255:117477. [PMID: 33436240 DOI: 10.1016/j.carbpol.2020.117477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 10/22/2022]
Abstract
The cell surface and extracellular matrix polysaccharide, heparan sulfate (HS) conveys chemical information to control crucial biological processes. HS chains are synthesized in a non-template driven process mainly in the Golgi apparatus, involving a large number of enzymes capable of subtly modifying its substitution pattern, hence, its interactions and biological effects. Changes in the localization of HS-modifying enzymes throughout the Golgi were found to correlate with changes in the structure of HS, rather than protein expression levels. Following BFA treatment, the HS-modifying enzymes localized preferentially in COPII vesicles and at the trans-Golgi. Shortly after heparin treatment, the HS-modifying enzyme moved from cis to trans-Golgi, which coincided with increased HS sulfation. Finally, it was shown that COPI subunits and Sec24 gene expression changed. Collectively, these findings demonstrate that knowledge of the ER-Golgi dynamics of HS-modifying enzymes via vesicular trafficking is a critical prerequisite for the complete delineation of HS biosynthesis.
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Affiliation(s)
- Maria C Z Meneghetti
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Paula Deboni
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Carlos M V Palomino
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Luiz P Braga
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Renan P Cavalheiro
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Gustavo M Viana
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Edwin A Yates
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil; Department of Biochemistry and Systems Biology, ISMIB, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Helena B Nader
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil
| | - Marcelo A Lima
- Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100, São Paulo, SP 04044-020, Brazil; Molecular & Structural Biosciences, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK.
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20
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Targeting the cytoskeleton against metastatic dissemination. Cancer Metastasis Rev 2021; 40:89-140. [PMID: 33471283 DOI: 10.1007/s10555-020-09936-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 10/08/2020] [Indexed: 02/08/2023]
Abstract
Cancer is a pathology characterized by a loss or a perturbation of a number of typical features of normal cell behaviour. Indeed, the acquisition of an inappropriate migratory and invasive phenotype has been reported to be one of the hallmarks of cancer. The cytoskeleton is a complex dynamic network of highly ordered interlinking filaments playing a key role in the control of fundamental cellular processes, like cell shape maintenance, motility, division and intracellular transport. Moreover, deregulation of this complex machinery contributes to cancer progression and malignancy, enabling cells to acquire an invasive and metastatic phenotype. Metastasis accounts for 90% of death from patients affected by solid tumours, while an efficient prevention and suppression of metastatic disease still remains elusive. This results in the lack of effective therapeutic options currently available for patients with advanced disease. In this context, the cytoskeleton with its regulatory and structural proteins emerges as a novel and highly effective target to be exploited for a substantial therapeutic effort toward the development of specific anti-metastatic drugs. Here we provide an overview of the role of cytoskeleton components and interacting proteins in cancer metastasis with a special focus on small molecule compounds interfering with the actin cytoskeleton organization and function. The emerging involvement of microtubules and intermediate filaments in cancer metastasis is also reviewed.
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21
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The p24 Complex Contributes to Specify Arf1 for COPI Coat Selection. Int J Mol Sci 2021; 22:ijms22010423. [PMID: 33401608 PMCID: PMC7794930 DOI: 10.3390/ijms22010423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/21/2020] [Accepted: 12/30/2020] [Indexed: 11/17/2022] Open
Abstract
Golgi trafficking depends on the small GTPase Arf1 which, upon activation, drives the assembly of different coats onto budding vesicles. Two related types of guanine nucleotide exchange factors (GEFs) activate Arf1 at different Golgi sites. In yeast, Gea1 in the cis-Golgi and Gea2 in the medial-Golgi activate Arf1 to form COPIcoated vesicles for retrograde cargo sorting, whereas Sec7 generates clathrin/adaptorcoated vesicles at the trans-Golgi network (TGN) for forward cargo transport. A central question is how the same activated Arf1 protein manages to assemble different coats depending on the donor Golgi compartment. A previous study has postulated that the interaction between Gea1 and COPI would channel Arf1 activation for COPI vesicle budding. Here, we found that the p24 complex, a major COPI vesicle cargo, promotes the binding of Gea1 with COPI by increasing the COPI association to the membrane independently of Arf1 activation. Furthermore, the p24 complex also facilitates the interaction of Arf1 with its COPI effector. Therefore, our study supports a mechanism by which the p24 complex contributes to program Arf1 activation by Gea1 for selective COPI coat assembly at the cis-Golgi compartment.
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Fujii S, Kurokawa K, Tago T, Inaba R, Takiguchi A, Nakano A, Satoh T, Satoh AK. Sec71 separates Golgi stacks in Drosophila S2 cells. J Cell Sci 2020; 133:jcs245571. [PMID: 33262309 PMCID: PMC10668125 DOI: 10.1242/jcs.245571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/18/2020] [Indexed: 01/19/2023] Open
Abstract
Golgi stacks are the basic structural units of the Golgi. Golgi stacks are separated from each other and scattered in the cytoplasm of Drosophila cells. Here, we report that the ARF-GEF inhibitor Brefeldin A (BFA) induces the formation of BFA bodies, which are aggregates of Golgi stacks, trans-Golgi networks and recycling endosomes. Recycling endosomes are located in the centers of BFA bodies, while Golgi stacks surround them on their trans sides. Live imaging of S2 cells revealed that Golgi stacks repeatedly merged and separated on their trans sides, and BFA caused successive merger by inhibiting separation, forming BFA bodies. S2 cells carrying genome-edited BFA-resistant mutant Sec71M717L did not form BFA bodies at high concentrations of BFA; S2 cells carrying genome-edited BFA-hypersensitive mutant Sec71F713Y produced BFA bodies at low concentrations of BFA. These results indicate that Sec71 is the sole BFA target for BFA body formation and controls Golgi stack separation. Finally, we showed that impairment of Sec71 in fly photoreceptors induces BFA body formation, with accumulation of both apical and basolateral cargoes, resulting in inhibition of polarized transport.
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Affiliation(s)
- Syara Fujii
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tatsuya Tago
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Ryota Inaba
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Arata Takiguchi
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takunori Satoh
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Akiko K Satoh
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
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Enterovirus Infection Induces Massive Recruitment of All Isoforms of Small Cellular Arf GTPases to the Replication Organelles. J Virol 2020; 95:JVI.01629-20. [PMID: 33087467 DOI: 10.1128/jvi.01629-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/18/2020] [Indexed: 12/12/2022] Open
Abstract
Enterovirus replication requires the cellular protein GBF1, a guanine nucleotide exchange factor for small Arf GTPases. When activated, Arfs associate with membranes, where they regulate numerous steps of membrane homeostasis. The requirement for GBF1 implies that Arfs are important for replication, but which of the different Arfs function(s) during replication remains poorly understood. Here, we established cell lines expressing each of the human Arfs fused to a fluorescent tag and investigated their behavior during enterovirus infection. Arf1 was the first to be recruited to the replication organelles, where it strongly colocalized with the viral antigen 2B and mature virions but not double-stranded RNA. By the end of the infectious cycle, Arf3, Arf4, Arf5, and Arf6 were also concentrated on the replication organelles. Once on the replication membranes, all Arfs except Arf3 were no longer sensitive to inhibition of GBF1, suggesting that in infected cells they do not actively cycle between GTP- and GDP-bound states. Only the depletion of Arf1, but not other class 1 and 2 Arfs, significantly increased the sensitivity of replication to GBF1 inhibition. Surprisingly, depletion of Arf6, a class 3 Arf, normally implicated in plasma membrane events, also increased the sensitivity to GBF1 inhibition. Together, our results suggest that GBF1-dependent Arf1 activation directly supports the development and/or functioning of the replication complexes and that Arf6 plays a previously unappreciated role in viral replication. Our data reveal a complex pattern of Arf activation in enterovirus-infected cells that may contribute to the resilience of viral replication in different cellular environments.IMPORTANCE Enteroviruses include many known and emerging pathogens, such as poliovirus, enteroviruses 71 and D68, and others. However, licensed vaccines are available only against poliovirus and enterovirus 71, and specific anti-enterovirus therapeutics are lacking. Enterovirus infection induces the massive remodeling of intracellular membranes and the development of specialized domains harboring viral replication complexes, replication organelles. Here, we investigated the roles of small Arf GTPases during enterovirus infection. Arfs control distinct steps in intracellular membrane traffic, and one of the Arf-activating proteins, GBF1, is a cellular factor required for enterovirus replication. We found that all Arfs expressed in human cells, including Arf6, normally associated with the plasma membrane, are recruited to the replication organelles and that Arf1 appears to be the most important Arf for enterovirus replication. These results document the rewiring of the cellular membrane pathways in infected cells and may provide new ways of controlling enterovirus infections.
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Protein-membrane interactions in small GTPase signalling and pharmacology: perspectives from Arf GTPases studies. Biochem Soc Trans 2020; 48:2721-2728. [PMID: 33336699 DOI: 10.1042/bst20200482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/17/2022]
Abstract
Small GTPases, in association with their GEFs, GAPs and effectors, control major intracellular processes such as signal transduction, cytoskeletal dynamics and membrane trafficking. Accordingly, dysfunctions in their biochemical properties are associated with many diseases, including cancers, diabetes, infections, mental disorders and cardiac diseases, which makes them attractive targets for therapies. However, small GTPases signalling modules are not well-suited for classical inhibition strategies due to their mode of action that combines protein-protein and protein-membrane interactions. As a consequence, there is still no validated drug available on the market that target small GTPases, whether directly or through their regulators. Alternative inhibitory strategies are thus highly needed. Here we review recent studies that highlight the unique modalities of the interaction of small GTPases and their GEFs at the periphery of membranes, and discuss how they can be harnessed in drug discovery.
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Parnell E, Shapiro LP, Voorn RA, Forrest MP, Jalloul HA, Loizzo DD, Penzes P. KALRN: A central regulator of synaptic function and synaptopathies. Gene 2020; 768:145306. [PMID: 33189799 DOI: 10.1016/j.gene.2020.145306] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/28/2020] [Accepted: 11/06/2020] [Indexed: 12/23/2022]
Abstract
The synaptic regulator, kalirin, plays a key role in synaptic plasticity and formation of dendritic arbors and spines. Dysregulation of the KALRN gene has been linked to various neurological disorders, including autism spectrum disorder, Alzheimer's disease, schizophrenia, addiction and intellectual disabilities. Both genetic and molecular studies highlight the importance of normal KALRN expression for healthy neurodevelopment and function. This review aims to give an in-depth analysis of the structure and molecular mechanisms of kalirin function, particularly within the brain. These data are correlated to genetic evidence of patient mutations within KALRN and animal models of Kalrn that together give insight into the manner in which this gene may be involved in neurodevelopment and the etiology of disease. The emerging links to human disease from post-mortem, genome wide association (GWAS) and exome sequencing studies are examined to highlight the disease relevance of kalirin, particularly in neurodevelopmental diseases. Finally, we will discuss efforts to pharmacologically regulate kalirin protein activity and the implications of such endeavors for the treatment of human disease. As multiple disease states arise from deregulated synapse formation and altered KALRN expression and function, therapeutics may be developed to provide control over KALRN activity and thus synapse dysregulation. As such, a detailed understanding of how kalirin regulates neuronal development, and the manner in which kalirin dysfunction promotes neurological disease, may support KALRN as a valuable therapeutic avenue for future pharmacological intervention.
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Affiliation(s)
- Euan Parnell
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA
| | - Lauren P Shapiro
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA
| | - Roos A Voorn
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA
| | - Marc P Forrest
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA
| | - Hiba A Jalloul
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA
| | - Daniel D Loizzo
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA
| | - Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA; Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, 60611 IL, USA; Northwestern University Center for Autism and Neurodevelopment, Chicago, IL 60611, USA.
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26
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Buelto D, Hung CW, Aoh QL, Lahiri S, Duncan MC. Plasma membrane to vacuole traffic induced by glucose starvation requires Gga2-dependent sorting at the trans-Golgi network. Biol Cell 2020; 112:349-367. [PMID: 32761633 DOI: 10.1111/boc.202000058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/27/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND INFORMATION In the yeast Saccharomyces cerevisiae, acute glucose starvation induces rapid endocytosis followed by vacuolar degradation of many plasma membrane proteins. This process is essential for cell viability, but the regulatory mechanisms that control it remain poorly understood. Under normal growth conditions, a major regulatory decision for endocytic cargo occurs at the trans-Golgi network (TGN) where proteins can recycle back to the plasma membrane or can be recognized by TGN-localised clathrin adaptors that direct them towards the vacuole. However, glucose starvation reduces recycling and alters the localization and post-translational modification of TGN-localised clathrin adaptors. This raises the possibility that during glucose starvation endocytosed proteins are routed to the vacuole by a novel mechanism that bypasses the TGN or does not require TGN-localised clathrin adaptors. RESULTS Here, we investigate the role of TGN-localised clathrin adaptors in the traffic of several amino acid permeases, including Can1, during glucose starvation. We find that Can1 transits through the TGN after endocytosis in both starved and normal conditions. Can1 and other amino acid permeases require TGN-localised clathrin adaptors for maximal delivery to the vacuole. Furthermore, these permeases are actively sorted to the vacuole, because ectopically forced de-ubiquitination at the TGN results in the recycling of the Tat1 permase in starved cells. Finally, we report that the Mup1 permease requires the clathrin adaptor Gga2 for vacuolar delivery. In contrast, the clathrin adaptor protein complex AP-1 plays a minor role, potentially in retaining permeases in the TGN, but it is otherwise dispensable for vacuolar delivery. CONCLUSIONS AND SIGNIFICANCE This work elucidates one membrane trafficking pathway needed for yeast to respond to acute glucose starvation. It also reveals the functions of TGNlocalised clathrin adaptors in this process. Our results indicate that the same machinery is needed for vacuolar protein sorting at the GN in glucose starved cells as is needed in the presence of glucose. In addition, our findings provide further support for the model that the TGN is a transit point for many endocytosed proteins, and that Gga2 and AP-1 function in distinct pathways at the TGN.
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Affiliation(s)
- Destiney Buelto
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Chao-Wei Hung
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.,Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Quyen L Aoh
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sagar Lahiri
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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Kotova A, Timonina K, Zoidl GR. Endocytosis of Connexin 36 is Mediated by Interaction with Caveolin-1. Int J Mol Sci 2020; 21:E5401. [PMID: 32751343 PMCID: PMC7432810 DOI: 10.3390/ijms21155401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/25/2020] [Accepted: 07/28/2020] [Indexed: 12/22/2022] Open
Abstract
The gap junctional protein connexin 36 (Cx36) has been co-purified with the lipid raft protein caveolin-1 (Cav-1). The relevance of an interaction between the two proteins is unknown. In this study, we explored the significance of Cav-1 interaction in the context of intracellular and membrane transport of Cx36. Coimmunoprecipitation assays and Förster resonance energy transfer analysis (FRET) were used to confirm the interaction between the two proteins in the Neuro 2a cell line. We found that the Cx36 and Cav-1 interaction was dependent on the intracellular calcium levels. By employing different microscopy techniques, we demonstrated that Cav-1 enhances the vesicular transport of Cx36. Pharmacological interventions coupled with cell surface biotinylation assays and FRET analysis revealed that Cav-1 regulates membrane localization of Cx36. Our data indicate that the interaction between Cx36 and Cav-1 plays a role in the internalization of Cx36 by a caveolin-dependent pathway.
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Affiliation(s)
- Anna Kotova
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (A.K.); (K.T.)
| | - Ksenia Timonina
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (A.K.); (K.T.)
| | - Georg R. Zoidl
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (A.K.); (K.T.)
- Department of Psychology, York University, Toronto, ON M3J 1P3, Canada
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28
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Marek M, Vincenzetti V, Martin SG. Sterol biosensor reveals LAM-family Ltc1-dependent sterol flow to endosomes upon Arp2/3 inhibition. J Cell Biol 2020; 219:e202001147. [PMID: 32320462 PMCID: PMC7265315 DOI: 10.1083/jcb.202001147] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 01/01/2023] Open
Abstract
Sterols are crucial components of biological membranes, which are synthetized in the ER and accumulate in the plasma membrane (PM). Here, by applying a genetically encoded sterol biosensor (D4H), we visualize a sterol flow between PM and endosomes in the fission yeast Schizosaccharomyces pombe. Using time-lapse and correlative light-electron microscopy, we found that inhibition of Arp2/3-dependent F-actin assembly promotes the reversible relocalization of D4H from the PM to internal sterol-rich compartments (STRIC) labeled by synaptobrevin Syb1. Retrograde sterol internalization to STRIC is independent of endocytosis or an intact Golgi, but depends on Ltc1, a LAM/StARkin-family protein localized to ER-PM contact sites. The PM in ltc1Δ cells over-accumulates sterols and upon Arp2/3 inhibition forms extended ER-interacting invaginations, indicating that sterol transfer contributes to PM size homeostasis. Anterograde sterol movement from STRIC is independent of canonical vesicular trafficking but requires Arp2/3, suggesting a novel role for this complex. Thus, transfer routes orthogonal to vesicular trafficking govern the flow of sterols in the cell.
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Affiliation(s)
| | | | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Switzerland
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29
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Gray JL, von Delft F, Brennan PE. Targeting the Small GTPase Superfamily through Their Regulatory Proteins. Angew Chem Int Ed Engl 2020; 59:6342-6366. [PMID: 30869179 PMCID: PMC7204875 DOI: 10.1002/anie.201900585] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/11/2019] [Indexed: 12/11/2022]
Abstract
The Ras superfamily of small GTPases are guanine-nucleotide-dependent switches essential for numerous cellular processes. Mutations or dysregulation of these proteins are associated with many diseases, but unsuccessful attempts to target the small GTPases directly have resulted in them being classed as "undruggable". The GTP-dependent signaling of these proteins is controlled by their regulators; guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs), and in the Rho and Rab subfamilies, guanine nucleotide dissociation inhibitors (GDIs). This review covers the recent small molecule and biologics strategies to target the small GTPases through their regulators. It seeks to critically re-evaluate recent chemical biology practice, such as the presence of PAINs motifs and the cell-based readout using compounds that are weakly potent or of unknown specificity. It highlights the vast scope of potential approaches for targeting the small GTPases in the future through their regulatory proteins.
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Affiliation(s)
- Janine L. Gray
- Structural Genomics ConsortiumUniversity of Oxford, NDMRBOld Road CampusOxfordOX3 7DQUK
- Target Discovery InstituteNuffield Department of MedicineUniversity of OxfordOld Road CampusOxfordOX3 7FZUK
- Diamond Light SourceHarwell Science and Innovation CampusDidcotOX11 0QXUK
| | - Frank von Delft
- Structural Genomics ConsortiumUniversity of Oxford, NDMRBOld Road CampusOxfordOX3 7DQUK
- Diamond Light SourceHarwell Science and Innovation CampusDidcotOX11 0QXUK
- Department of BiochemistryUniversity of JohannesburgAuckland Park2006South Africa
| | - Paul E. Brennan
- Structural Genomics ConsortiumUniversity of Oxford, NDMRBOld Road CampusOxfordOX3 7DQUK
- Target Discovery InstituteNuffield Department of MedicineUniversity of OxfordOld Road CampusOxfordOX3 7FZUK
- Alzheimer's Research (UK) Oxford Drug Discovery InstituteNuffield Department of MedicineUniversity of OxfordOxfordOX3 7FZUK
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30
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Deshaies RJ. Multispecific drugs herald a new era of biopharmaceutical innovation. Nature 2020; 580:329-338. [DOI: 10.1038/s41586-020-2168-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
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31
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Gray JL, Delft F, Brennan PE. Targeting der kleinen GTPasen über ihre regulatorischen Proteine. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201900585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Janine L. Gray
- Structural Genomics ConsortiumUniversity of Oxford, NDMRB Old Road Campus Oxford OX3 7DQ Großbritannien
- Target Discovery InstituteNuffield Department of MedicineUniversity of Oxford Old Road Campus Oxford OX3 7FZ Großbritannien
- Diamond Light Source Harwell Science and Innovation Campus Didcot OX11 0QX Großbritannien
| | - Frank Delft
- Structural Genomics ConsortiumUniversity of Oxford, NDMRB Old Road Campus Oxford OX3 7DQ Großbritannien
- Diamond Light Source Harwell Science and Innovation Campus Didcot OX11 0QX Großbritannien
- Department of BiochemistryUniversity of Johannesburg Auckland Park 2006 Südafrika
| | - Paul E. Brennan
- Structural Genomics ConsortiumUniversity of Oxford, NDMRB Old Road Campus Oxford OX3 7DQ Großbritannien
- Target Discovery InstituteNuffield Department of MedicineUniversity of Oxford Old Road Campus Oxford OX3 7FZ Großbritannien
- Alzheimer's Research (UK) Oxford Drug Discovery InstituteNuffield Department of MedicineUniversity of Oxford Oxford OX3 7FZ Großbritannien
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Design and Synthesis of Arf1-Targeting γ-Dipeptides as Potential Agents against Head and Neck Squamous Cell Carcinoma. Cells 2020; 9:cells9020286. [PMID: 31991585 PMCID: PMC7072570 DOI: 10.3390/cells9020286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/24/2022] Open
Abstract
Background: Head and neck squamous cell carcinoma (HNSCC) is one of the leading causes of cancer-related deaths and calls for new druggable targets. We have previously highlighted the critical role of ADP-ribosylation factor-1 (Arf1) activation in HNSCC. In the present study, we address the question whether targeting Arf1 could be proposed as a valuable strategy against HNSCC. Methods: We rationally designed and synthesized constrained ATC-based (4-amino-(methyl)-1,3-thiazole-5-carboxylic acid) γ-dipeptides to block Arf1 activation. We evaluated the effects of these γ-dipeptides in HNSCC cells: The cell viability was determined in 2D and 3D cell cultures after 72 h treatment and Arf1 protein levels and activity were assessed by GGA3 pull-down and Western blotting assays. Results: Targeting Arf1 offers a valuable strategy to counter HNSCC. Our new Arf1-targeting compounds revealed a strong in vitro cytotoxicity against HNSCC cells, through inhibiting Arf1 activation and its downstream pathways. Conclusions: Arf1-targeting γ-dipeptides developed in this study may represent a promising targeted therapeutic to improve managing the HNSCC disease.
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Frisbie CP, Lushnikov AY, Krasnoslobodtsev AV, Riethoven JJM, Clarke JL, Stepchenkova EI, Petrosyan A. Post-ER Stress Biogenesis of Golgi Is Governed by Giantin. Cells 2019; 8:E1631. [PMID: 31847122 PMCID: PMC6953117 DOI: 10.3390/cells8121631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The Golgi apparatus undergoes disorganization in response to stress, but it is able to restore compact and perinuclear structure under recovery. This self-organization mechanism is significant for cellular homeostasis, but remains mostly elusive, as does the role of giantin, the largest Golgi matrix dimeric protein. METHODS In HeLa and different prostate cancer cells, we used the model of cellular stress induced by Brefeldin A (BFA). The conformational structure of giantin was assessed by proximity ligation assay and atomic force microscopy. The post-BFA distribution of Golgi resident enzymes was examined by 3D SIM high-resolution microscopy. RESULTS We detected that giantin is rather flexible than an extended coiled-coil dimer and BFA-induced Golgi disassembly was associated with giantin monomerization. A fusion of the nascent Golgi membranes after BFA washout is forced by giantin re-dimerization via disulfide bond in its luminal domain and assisted by Rab6a GTPase. GM130-GRASP65-dependent enzymes are able to reach the nascent Golgi membranes, while giantin-sensitive enzymes appeared at the Golgi after its complete recovery via direct interaction of their cytoplasmic tail with N-terminus of giantin. CONCLUSION Post-stress recovery of Golgi is conducted by giantin dimer and Golgi proteins refill membranes according to their docking affiliation rather than their intra-Golgi location.
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Affiliation(s)
- Cole P. Frisbie
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA;
| | - Alexander Y. Lushnikov
- Nanoimaging Core Facility, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (A.Y.L.); (A.V.K.)
| | - Alexey V. Krasnoslobodtsev
- Nanoimaging Core Facility, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (A.Y.L.); (A.V.K.)
- Department of Physics, University of Nebraska-Omaha, Omaha, NE 68182-0266, USA
| | - Jean-Jack M. Riethoven
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68588-0665, USA;
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA;
| | - Jennifer L. Clarke
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA;
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, NE 68583-0963, USA
| | - Elena I. Stepchenkova
- Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, Saint-Petersburg 199034, Russia;
- Department of Genetics, Saint-Petersburg State University, Saint-Petersburg 199034, Russia
| | - Armen Petrosyan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA;
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA;
- The Fred and Pamela Buffett Cancer Center, Omaha, NE 68198-5870, USA
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Chan CJ, Le R, Burns K, Ahmed K, Coyaud E, Laurent EMN, Raught B, Melançon P. BioID Performed on Golgi Enriched Fractions Identify C10orf76 as a GBF1 Binding Protein Essential for Golgi Maintenance and Secretion. Mol Cell Proteomics 2019; 18:2285-2297. [PMID: 31519766 PMCID: PMC6823846 DOI: 10.1074/mcp.ra119.001645] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/04/2019] [Indexed: 12/29/2022] Open
Abstract
The Golgi-specific Brefeldin-A resistance factor 1 (GBF1) is the only large GEF that regulates Arf activation at the cis-Golgi and is actively recruited to membranes on an increase in Arf-GDP. Recent studies have revealed that GBF1 recruitment requires one or more heat-labile and protease-sensitive protein factor(s) (Quilty et al., 2018, J. Cell Science, 132). Proximity-dependent biotinylation (BioID) and mass spectrometry from enriched Golgi fractions identified GBF1 proximal proteins that may regulate its recruitment. Knockdown studies revealed C10orf76 to be involved in Golgi maintenance. We find that C10orf76 interacts with GBF1 and rapidly cycles on and off GBF1-positive Golgi structures. More importantly, its depletion causes Golgi fragmentation, alters GBF1 recruitment, and impairs secretion. Homologs were identified in most species, suggesting its presence in the last eukaryotic common ancestor.
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Affiliation(s)
- Calvin J Chan
- Department of Cell Biology, University of Alberta, Edmonton, AB, T6G 2H7
| | - Roberta Le
- Department of Cell Biology, University of Alberta, Edmonton, AB, T6G 2H7
| | - Kaylan Burns
- Department of Cell Biology, University of Alberta, Edmonton, AB, T6G 2H7
| | - Khadra Ahmed
- Department of Cell Biology, University of Alberta, Edmonton, AB, T6G 2H7
| | - Etienne Coyaud
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Estelle M N Laurent
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Brian Raught
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Paul Melançon
- Department of Cell Biology, University of Alberta, Edmonton, AB, T6G 2H7.
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Dejgaard SY, Presley JF. Rab18 regulates lipolysis via Arf/GBF1 and adipose triglyceride lipase. Biochem Biophys Res Commun 2019; 520:526-531. [PMID: 31610914 DOI: 10.1016/j.bbrc.2019.10.069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 10/06/2019] [Indexed: 01/09/2023]
Abstract
Rab18 is a small GTPase associated with lipid droplets and other membranes. While it likely has multiple functions on lipid droplets, one proposed function is regulation of lipolysis. Previous work has concentrated on regulation of autophagy; however, in this study, we provide evidence that Rab18 plays a role upstream of the cytosolic lipolytic enzyme adipose triglyceride lipase (ATGL) and that recruitment of ATGL by Rab18 is mediated by elements of the Arf/GBF1 machinery. We find that Arf4-GFP is accumulated on the subset of lipid droplets associated with Rab18, and that this association is lost within 5 min upon treatment with 5 μg/ml of the drug brefeldin A, which targets GBF1 and other Sec7-domain containing Arf exchange factors. ATGL-GFP is also recruited to lipid droplets, but is lost more slowly after treatment with 5 μg/ml brefeldin A, with significant loss from lipid droplets after 1 h treatment, and almost complete loss from lipid droplets 4 h after brefeldin A treatment. Upon overexpression of the dominant negative GDP-locked cerulean-Rab18-S22 N, GFP-ATGL and Arf4 are lost from the surface of lipid droplets similarly to BFA treatment. This study establishes, for the first time, an essential role for Rab18 in recruiting ATGL to lipid droplets.
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Affiliation(s)
- Selma Yilmaz Dejgaard
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada; Department of Medical Biology, Near East University, Nicosia, Cyprus
| | - John F Presley
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
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Valeur E, Narjes F, Ottmann C, Plowright AT. Emerging modes-of-action in drug discovery. MEDCHEMCOMM 2019; 10:1550-1568. [PMID: 31673315 PMCID: PMC6786009 DOI: 10.1039/c9md00263d] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022]
Abstract
An increasing focus on complex biology to cure diseases rather than merely treat symptoms has transformed how drug discovery can be approached. Instead of activating or blocking protein function, a growing repertoire of drug modalities can be leveraged or engineered to hijack cellular processes, such as translational regulation or degradation mechanisms. Drug hunters can therefore access a wider arsenal of modes-of-action to modulate biological processes and this review summarises these emerging strategies by highlighting the most representative examples of these approaches.
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Affiliation(s)
- Eric Valeur
- Medicinal Chemistry , Research and Early Development, Cardiovascular, Renal & Metabolism , BioPharmaceuticals R&D , AstraZeneca, Gothenburg , 43183 Mölndal , Sweden .
| | - Frank Narjes
- Medicinal Chemistry , Research and Early Development, Respiratory, Inflammation and Autoimmune (RIA) , BioPharmaceuticals R&D , AstraZeneca, Gothenburg , 43183 Mölndal , Sweden
| | - Christian Ottmann
- Department of Biomedical Engineering and Institute for Complex Molecular Systems , Technische Universiteit Eindhoven , Den Dolech 2 , 5612 , AZ , Eindhoven , the Netherlands
- Department of Chemistry , University of Duisburg-Essen , Universitätsstraße 7 , 45117 , Essen , Germany
| | - Alleyn T Plowright
- Integrated Drug Discovery , Sanofi-Aventis Deutschland GmbH , Industriepark Höchst , D-65926 Frankfurt am Main , Germany
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Li C, Pang AP, Yang H, Lv R, Zhou Z, Wu FG, Lin F. Tracking localization and secretion of cellulase spatiotemporally and directly in living Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:200. [PMID: 31452681 PMCID: PMC6700804 DOI: 10.1186/s13068-019-1538-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 08/04/2019] [Indexed: 05/28/2023]
Abstract
BACKGROUND Filamentous fungi secret hydrolytic enzymes like cellulase and hemicellulase outside the cells, serving as important scavengers of plant biomass in nature and workhorses in the enzyme industry. Unlike the extensive study on the mechanism of cellulase production in fungi, research on spatiotemporal distribution and secretion of cellulase in fungi is lacking, retarding the deeper understanding of the molecular mechanism behind the fungal cellulase production. RESULT Recombinant Trichoderma reesei strains RBGL, RCBH, and RCMC were successfully constructed from T. reesei RUT-C30, expressing red fluorescent protein DsRed-tagged versions of β-glucosidase (BGL), cellobiohydrolase (CBH), and endoglucanase (CMC), respectively. With the assistance of these strains, we found that all three cellulase components BGL, CBH, and CMC diffused throughout the whole fungal mycelium with major accumulation at the hyphal apexes. These enzymes located in ER, Golgi, vacuoles and cell membrane/wall, but not septum, and secreted abundantly into the culture medium. Moreover, the major secretion of CBH and CMC started more early than that of BGL. Brefeldin A (BFA) completely blocked cellulase expression and secretion in T. reesei. CONCLUSION Based on recombinant T. reesei RBGL, RCBH, and RCMC expressing DsRed-fused versions of BGL, CBH, and CMC, respectively, the distribution and secretion of cellulase production in T. reesei were first visualized directly in a dynamic way, preliminarily mapping the location and secretion of T. reesei cellulase and providing evidence for revealing the secretion pathways of cellulase in T. reesei. The obtained results suggest that cellulase excretion majorly occurs via the conventional ER-Golgi secretory pathway, and might be assisted through unconventional protein secretion pathways.
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Affiliation(s)
- Chengcheng Li
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 37 Jinxianghe Road, Xuanwu District, Nanjing, 210096 Jiangsu China
| | - Ai-Ping Pang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 37 Jinxianghe Road, Xuanwu District, Nanjing, 210096 Jiangsu China
| | - Hang Yang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 37 Jinxianghe Road, Xuanwu District, Nanjing, 210096 Jiangsu China
| | - Roujing Lv
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 37 Jinxianghe Road, Xuanwu District, Nanjing, 210096 Jiangsu China
| | - Zhihua Zhou
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032 China
| | - Fu-Gen Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 37 Jinxianghe Road, Xuanwu District, Nanjing, 210096 Jiangsu China
| | - Fengming Lin
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, 37 Jinxianghe Road, Xuanwu District, Nanjing, 210096 Jiangsu China
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Abstract
ADP-ribosylation (ADPr) is an ancient reversible modification of cellular macromolecules controlling major biological processes as diverse as DNA damage repair, transcriptional regulation, intracellular transport, immune and stress responses, cell survival and proliferation. Furthermore, enzymatic reactions of ADPr are central in the pathogenesis of many human diseases, including infectious conditions. By providing a review of ADPr signalling in bacterial systems, we highlight the relevance of this chemical modification in the pathogenesis of human diseases depending on host-pathogen interactions. The post-antibiotic era has raised the need to find alternative approaches to antibiotic administration, as major pathogens becoming resistant to antibiotics. An in-depth understanding of ADPr reactions provides the rationale for designing novel antimicrobial strategies for treatment of infectious diseases. In addition, the understanding of mechanisms of ADPr by bacterial virulence factors offers important hints to improve our knowledge on cellular processes regulated by eukaryotic homologous enzymes, which are often involved in the pathogenesis of human diseases.
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Pipaliya SV, Schlacht A, Klinger CM, Kahn RA, Dacks J. Ancient complement and lineage-specific evolution of the Sec7 ARF GEF proteins in eukaryotes. Mol Biol Cell 2019; 30:1846-1863. [PMID: 31141460 PMCID: PMC6727740 DOI: 10.1091/mbc.e19-01-0073] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Guanine nucleotide exchange factors (GEFs) are the initiators of signaling by every regulatory GTPase, which in turn act to regulate a wide array of essential cellular processes. To date, each family of GTPases is activated by distinct families of GEFs. Bidirectional membrane trafficking is regulated by ADP-ribosylation factor (ARF) GTPases and the development throughout eukaryotic evolution of increasingly complex systems of such traffic required the acquisition of a functionally diverse cohort of ARF GEFs to control it. We performed phylogenetic analyses of ARF GEFs in eukaryotes, defined by the presence of the Sec7 domain, and found three subfamilies (BIG, GBF1, and cytohesins) to have been present in the ancestor of all eukaryotes. The four other subfamilies (EFA6/PSD, IQSEC7/BRAG, FBX8, and TBS) are opisthokont, holozoan, metazoan, and alveolate/haptophyte specific, respectively, and each is derived from cytohesins. We also identified a cytohesin-derived subfamily, termed ankyrin repeat-containing cytohesin, that independently evolved in amoebozoans and members of the SAR and haptophyte clades. Building on evolutionary data for the ARF family GTPases and their GTPase--activating proteins allowed the generation of hypotheses about ARF GEF protein function(s) as well as a better understanding of the origins and evolution of cellular complexity in eukaryotes.
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Affiliation(s)
- Shweta V Pipaliya
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Alexander Schlacht
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Christen M Klinger
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada
| | - Richard A Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Joel Dacks
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada.,Department of Life Sciences, The Natural History Museum, London SW7 5BD, United Kingdom
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Sztul E, Chen PW, Casanova JE, Cherfils J, Dacks JB, Lambright DG, Lee FJS, Randazzo PA, Santy LC, Schürmann A, Wilhelmi I, Yohe ME, Kahn RA. ARF GTPases and their GEFs and GAPs: concepts and challenges. Mol Biol Cell 2019; 30:1249-1271. [PMID: 31084567 PMCID: PMC6724607 DOI: 10.1091/mbc.e18-12-0820] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/26/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022] Open
Abstract
Detailed structural, biochemical, cell biological, and genetic studies of any gene/protein are required to develop models of its actions in cells. Studying a protein family in the aggregate yields additional information, as one can include analyses of their coevolution, acquisition or loss of functionalities, structural pliability, and the emergence of shared or variations in molecular mechanisms. An even richer understanding of cell biology can be achieved through evaluating functionally linked protein families. In this review, we summarize current knowledge of three protein families: the ARF GTPases, the guanine nucleotide exchange factors (ARF GEFs) that activate them, and the GTPase-activating proteins (ARF GAPs) that have the ability to both propagate and terminate signaling. However, despite decades of scrutiny, our understanding of how these essential proteins function in cells remains fragmentary. We believe that the inherent complexity of ARF signaling and its regulation by GEFs and GAPs will require the concerted effort of many laboratories working together, ideally within a consortium to optimally pool information and resources. The collaborative study of these three functionally connected families (≥70 mammalian genes) will yield transformative insights into regulation of cell signaling.
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Affiliation(s)
- Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, MA 01267
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS and Ecole Normale Supérieure Paris-Saclay, 94235 Cachan, France
| | - Joel B. Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - David G. Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Amherst, MA 01605
| | - Fang-Jen S. Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | | | - Lorraine C. Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Annette Schürmann
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Ilka Wilhelmi
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Marielle E. Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050
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Ashraf MA, Rahman A. Cold stress response in Arabidopsis thaliana is mediated by GNOM ARF-GEF. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:500-516. [PMID: 30362633 DOI: 10.1111/tpj.14137] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 10/14/2018] [Accepted: 10/16/2018] [Indexed: 05/29/2023]
Abstract
Endosomal trafficking plays an important role in regulating plant growth and development both at optimal and stressed conditions. Cold stress response in Arabidopsis root is directly linked to inhibition of the endosomal trafficking of auxin efflux carriers. However, the cellular components that link cold stress and the endosomal trafficking remain elusive. By screening available endosomal trafficking mutants against root growth recovery response under cold stress, we identified GNOM, a SEC7 containing ARF-GEF, as a major modulator of cold response. Contrasting response of partial loss of function mutant gnomB4049/emb30-1 and the engineered Brefeldin A (BFA)-resistant GNOM line, both of which contain mutations within SEC7 domain, to cold stress at the whole-plant level highlights the importance of this domain in modulating the cold response pathway of plants. Cold stress selectively and transiently inhibits GNOM expression. The engineered point mutation at 696 amino acid position (Methionine to Leucine) that makes GNOM resistant to BFA in fact results in overexpression of GNOM both at transcriptional and translational levels, and also alters its subcellular localization. Overexpression and altered cellular localization of GNOM were found to be directly linked to conferring striking cold-resistant phenotype in Arabidopsis. Collectively, these results provide a mechanistic link between GNOM, BFA-sensitive GNOM-regulated trafficking and cold stress.
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Affiliation(s)
- Mohammad A Ashraf
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, 020-8550, Japan
| | - Abidur Rahman
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, 020-8550, Japan
- Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan
- Agro-Innovation Center, Iwate University, Morioka, Japan
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Zhang M, Sun H, Deng Y, Su M, Wei S, Wang P, Yu L, Liu J, Guo J, Wang X, Han X, He Q, Shen L. COPI-Mediated Nuclear Translocation of EGFRvIII Promotes STAT3 Phosphorylation and PKM2 Nuclear Localization. Int J Biol Sci 2019; 15:114-126. [PMID: 30662352 PMCID: PMC6329918 DOI: 10.7150/ijbs.28679] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 09/26/2018] [Indexed: 12/17/2022] Open
Abstract
As a non-ligand-dependent activation protein, EGFRvIII is the most common mutant of EGFR, and its existence or especially its nuclear translocation in tumors can exacerbate the malignancy. Compared with the nuclear translocation of EGFR, which has been studied extensively, the specific mechanism by which EGFRvIII undergoes nuclear translocation has not yet been reported. Here, we found that EGFRvIII eventually reached the nucleus with the involvement of the Golgi and endoplasmic reticulum (ER) in glioma cells. In this process, syntaxin-6 was responsible for the identification and transport of EGFRvIII on Golgi. We also demonstrated that COPI mediated the reverse transport of EGFRvIII from the Golgi to ER, which process was also important for EGFRvIII's nuclear accumulation. EGFRvIII's nuclear translocation can significantly promote STAT3 phosphorylation and PKM2 nuclear localization. Finally, we showed that EGFRvIII's nuclear translocation obviously induced the growth of gliomas in an intracranial xenotransplantation experiment. These data suggested that searching methods that inhibit EGFRvIII entry into the nucleus will be effective glioma treatments.
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Affiliation(s)
- Mingzhi Zhang
- Department of Cell Biology, Stem Cell Research Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, People's Republic of China
| | - Haojie Sun
- Neuroscience Research Institute, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, People's Republic of China
| | - Yue Deng
- Beijing Cellonis Biotechnologies Co. Ltd, Zhongguancun Bio-Medicine Park, Beijing, People's Republic of China
| | - Ming Su
- Department of Cell Biology, Stem Cell Research Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, People's Republic of China
| | - Shiruo Wei
- Department of Cell Biology, Stem Cell Research Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, People's Republic of China
| | - Peipei Wang
- Beijing Cellonis Biotechnologies Co. Ltd, Zhongguancun Bio-Medicine Park, Beijing, People's Republic of China
| | - Lanlan Yu
- Beijing DongFang YaMei Gene Science and Technology Research Institute, Beijing, People's Republic of China
| | - Jinwen Liu
- Beijing DongFang YaMei Gene Science and Technology Research Institute, Beijing, People's Republic of China
| | - Jinhai Guo
- Beijing DongFang YaMei Gene Science and Technology Research Institute, Beijing, People's Republic of China
| | - Xuan Wang
- Research Center of Artificial Organ and Tissue Engineering, Second Department of Hepatobiliary Surgery, ZhuJiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Xu Han
- Research Center of Artificial Organ and Tissue Engineering, Second Department of Hepatobiliary Surgery, ZhuJiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Qihua He
- Medical and Health Analytical Center, Peking University Health Science Center, People's Republic of China
| | - Li Shen
- Department of Cell Biology, Stem Cell Research Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, People's Republic of China
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Hernández-González M, Bravo-Plaza I, de Los Ríos V, Pinar M, Pantazopoulou A, Peñalva MA. COPI localizes to the early Golgi in Aspergillus nidulans. Fungal Genet Biol 2018; 123:78-86. [PMID: 30550852 DOI: 10.1016/j.fgb.2018.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 01/21/2023]
Abstract
Coatomer-I (COPI) is a heteromeric protein coat that facilitates the budding of membranous carriers mediating Golgi-to-ER and intra-Golgi transport. While the structural features of COPI have been thoroughly investigated, its physiological role is insufficiently understood. Here we exploit the amenability of A. nidulans for studying intracellular traffic, taking up previous studies by Breakspear et al. (2007) with the α-COP/CopA subunit of COPI. Endogenously tagged α-COP/CopA largely localizes to SedVSed5 syntaxin-containing early Golgi cisterna, and acute inactivation of ER-to-Golgi traffic delocalizes COPI to a haze, consistent with the cisternal maturation model. In contrast, the Golgi localization of COPI is independent of the TGN regulators HypBSec7 and HypATrs120, implying that COPI budding predominates at the SedVSed5 early Golgi, with lesser contribution of the TGN. This finding agrees with the proposed role of COPI-mediated intra-Golgi retrograde traffic in driving cisternal maturation, which predicts that the capacity of the TGN to generate COPI carriers is low. The COPI early Golgi compartments intimately associates with Sec13-containing ER exit sites. Characterization of the heat-sensitive copA1ts (sodVIC1) mutation showed that it results in a single residue substitution in the ε-COP-binding Carboxyl-Terminal-Domain of α-COP that likely destabilizes its folding. However, we show that Golgi disorganization by copA1ts necessitates >150 min-long incubation at 42 °C. This weak subcellular phenotype makes it unsuitable for inactivating COPI traffic acutely for microscopy studies, and explains the aneuploidy-stabilizing role of the mutation at subrestrictive temperatures.
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Affiliation(s)
- Miguel Hernández-González
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain; Centre for Mechanochemical Cell Biology, Gibbet Hill Road, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK(1)
| | - Ignacio Bravo-Plaza
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Vivian de Los Ríos
- Proteomics and Genomics Facility, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain; Department of Molecular Genetics and Cell Biology, Biological Sciences Division, The University of Chicago, United States(1).
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain.
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Walch L, Pellier E, Leng W, Lakisic G, Gautreau A, Contremoulins V, Verbavatz JM, Jackson CL. GBF1 and Arf1 interact with Miro and regulate mitochondrial positioning within cells. Sci Rep 2018; 8:17121. [PMID: 30459446 PMCID: PMC6244289 DOI: 10.1038/s41598-018-35190-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/28/2018] [Indexed: 02/08/2023] Open
Abstract
The spatial organization of cells depends on coordination between cytoskeletal systems and intracellular organelles. The Arf1 small G protein and its activator GBF1 are important regulators of Golgi organization, maintaining its morphology and function. Here we show that GBF1 and its substrate Arf1 regulate the spatial organization of mitochondria in a microtubule-dependent manner. Miro is a mitochondrial membrane protein that interacts through adaptors with microtubule motor proteins such as cytoplasmic dynein, the major microtubule minus end directed motor. We demonstrate a physical interaction between GBF1 and Miro, and also between the active GTP-bound form of Arf1 and Miro. Inhibition of GBF1, inhibition of Arf1 activation, or overexpression of Miro, caused a collapse of the mitochondrial network towards the centrosome. The change in mitochondrial morphology upon GBF1 inhibition was due to a two-fold increase in the time engaged in retrograde movement compared to control conditions. Electron tomography revealed that GBF1 inhibition also resulted in larger mitochondria with more complex morphology. Miro silencing or drug inhibition of cytoplasmic dynein activity blocked the GBF1-dependent repositioning of mitochondria. Our results show that blocking GBF1 function promotes dynein- and Miro-dependent retrograde mitochondrial transport along microtubules towards the microtubule-organizing center, where they form an interconnected network.
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Affiliation(s)
- Laurence Walch
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Emilie Pellier
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Weihua Leng
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Goran Lakisic
- CNRS UMR7654, Ecole Polytechnique, Palaiseau, France
| | | | - Vincent Contremoulins
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Jean-Marc Verbavatz
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.
| | - Catherine L Jackson
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.
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Wu J, Chen S, Liu H, Zhang Z, Ni Z, Chen J, Yang Z, Nie Y, Fan D. Tunicamycin specifically aggravates ER stress and overcomes chemoresistance in multidrug-resistant gastric cancer cells by inhibiting N-glycosylation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2018; 37:272. [PMID: 30413206 PMCID: PMC6230241 DOI: 10.1186/s13046-018-0935-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/18/2018] [Indexed: 02/06/2023]
Abstract
Background Multidrug resistance remains a major obstacle to successful treatment for patients with gastric cancer (GC). Recently, glycosylation has been demonstrated to play a vital role in the acquisition of multidrug resistance. As a potent inhibitor of glycosylation, tunicamycin (Tu) has shown marked antitumor activities in various cancers. In the present study, we attempted to determine the exact effect of Tu on the chemoresistance of GC. Methods The cytotoxic effects of drugs on GC cells were evaluated by cell viability assays, and apoptosis was detected by flow cytometry. PCR, western blot analysis, immunofluorescence staining and canonical inhibitors were employed to identify the underlying mechanisms of the specific effects of Tu on multidrug-resistant (MDR) GC cells. Results For the first time, we found that MDR GC cells were more sensitive to Tu-induced cell death than the parental cells and that the increased sensitivity might correlate with basal endoplasmic reticulum (ER) stress. In addition, Tu dramatically increased chemotherapy-induced apoptosis by evoking ER stress in GC cells, particularly MDR cells. Further study indicated that these effects were highly dependent on glycosylation inhibition by Tu, rather than its role as a canonical ER stress inducer. Besides, autophagy was markedly triggered by Tu, and blocking autophagy enhanced the combined effects of Tu and chemotherapy on MDR GC cells. Conclusions Our results suggest that tumor-targeted glycosylation inhibition may be a feasible strategy to reverse chemoresistance in GC patients. Electronic supplementary material The online version of this article (10.1186/s13046-018-0935-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian Wu
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Sheng Chen
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Hao Liu
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Zhe Zhang
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Zhen Ni
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Jie Chen
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Zhiping Yang
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Yongzhan Nie
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China.
| | - Daiming Fan
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, 127 West Changle Road, Xi'an, 710032, Shaanxi, China.
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Chakraborti S, Sarkar J, Bhuyan R, Chakraborti T. Role of catechins on ET-1-induced stimulation of PLD and NADPH oxidase activities in pulmonary smooth muscle cells: determination of the probable mechanism by molecular docking studies. Biochem Cell Biol 2018; 96:417-432. [PMID: 29206487 DOI: 10.1139/bcb-2017-0179] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The treatment of human pulmonary artery smooth muscle cells with ET-1 stimulates the activity of PLD and NADPH oxidase, but this stimulation is inhibited by pretreatment with bosentan (ET-1 receptor antagonist), FIPI (PLD inhibitor), apocynin (NADPH oxidase inhibitor), and EGCG and ECG (catechins having a galloyl group), but not EGC and EC (catechins devoid of a galloyl group). Herein, using molecular docking analyses based on our biochemical studies, we determined the probable mechanism by which the catechins containing a galloyl group inhibit the stimulation of PLD activity induced by ET-1. The ET-1-induced stimulation of PLD activity was inhibited by SecinH3 (inhibitor of cytohesin). Arf6 and cytohesin-1 are associated in the cell membrane, which is not inhibited by the catechins during ET-1 treatment of the cells. However, EGCG and ECG inhibited the binding of GTPγS with Arf6, even in the presence of cytohesin-1. The molecular docking analyses revealed that the catechins containing a galloyl group (EGCG and ECG) with cytohesin-1–Arf6GDP, but not the catechins without a galloyl group (EGC and EC), prevent GDP–GTP exchange in Arf6, which seems to be an important mechanism for inhibiting the activation of PLD induced by ET-1, and subsequently increases the activity of NADPH oxidase.
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Affiliation(s)
- Sajal Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
| | - Jaganmay Sarkar
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
| | - Rajabrata Bhuyan
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
| | - Tapati Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
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Jha SG, Larson ER, Humble J, Domozych DS, Barrington DS, Tierney ML. Vacuolar Protein Sorting 26C encodes an evolutionarily conserved large retromer subunit in eukaryotes that is important for root hair growth in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:595-611. [PMID: 29495075 DOI: 10.1111/tpj.13880] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 02/09/2018] [Accepted: 02/14/2018] [Indexed: 05/24/2023]
Abstract
The large retromer complex participates in diverse endosomal trafficking pathways and is essential for plant developmental programs, including cell polarity, programmed cell death and shoot gravitropism in Arabidopsis. Here we demonstrate that an evolutionarily conserved VPS26 protein (VPS26C; At1G48550) functions in a complex with VPS35A and VPS29 necessary for root hair growth in Arabidopsis. Bimolecular fluorescence complementation showed that VPS26C forms a complex with VPS35A in the presence of VPS29, and this is supported by genetic studies showing that vps29 and vps35a mutants exhibit altered root hair growth. Genetic analysis also demonstrated an interaction between a VPS26C trafficking pathway and one involving the SNARE VTI13. Phylogenetic analysis indicates that VPS26C, with the notable exception of grasses, has been maintained in the genomes of most major plant clades since its evolution at the base of eukaryotes. To test the model that VPS26C orthologs in animal and plant species share a conserved function, we generated transgenic lines expressing GFP fused with the VPS26C human ortholog (HsDSCR3) in a vps26c background. These studies illustrate that GFP-HsDSCR3 is able to complement the vps26c root hair phenotype in Arabidopsis, indicating a deep conservation of cellular function for this large retromer subunit across plant and animal kingdoms.
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Affiliation(s)
- Suryatapa Ghosh Jha
- Department of Plant Biology, University of Vermont, Burlington, Vermont, 05405, USA
| | - Emily R Larson
- Department of Plant Biology, University of Vermont, Burlington, Vermont, 05405, USA
| | - Jordan Humble
- Department of Plant Biology, University of Vermont, Burlington, Vermont, 05405, USA
| | | | - David S Barrington
- Department of Plant Biology, University of Vermont, Burlington, Vermont, 05405, USA
| | - Mary L Tierney
- Department of Plant Biology, University of Vermont, Burlington, Vermont, 05405, USA
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48
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Kirschner GK, Stahl Y, Imani J, von Korff M, Simon R. Fluorescent reporter lines for auxin and cytokinin signalling in barley (Hordeum vulgare). PLoS One 2018; 13:e0196086. [PMID: 29694399 PMCID: PMC5918912 DOI: 10.1371/journal.pone.0196086] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/05/2018] [Indexed: 11/18/2022] Open
Abstract
The phytohormones auxin and cytokinin control development and maintenance of plant meristems and stem cell systems. Fluorescent protein reporter lines that monitor phytohormone controlled gene expression programmes have been widely used to study development and differentiation in the model species Arabidopsis, but equivalent tools are still missing for the majority of crop species. Barley (Hordeum vulgare) is the fourth most abundant cereal crop plant, but knowledge on these important phytohormones in regard to the barley root and shoot stem cell niches is still negligible. We have now analysed the role of auxin and cytokinin in barley root meristem development, and present fluorescent protein reporter lines that allow to dissect auxin and cytokinin signalling outputs in vivo. We found that application of either auxin or cytokinin to barley seedlings negatively impacts root meristem growth. We further established a barley cytokinin reporter, TCSnew, which revealed significant cytokinin signalling in the stele cells proximal to the QC, and in the differentiated root cap cells. Application of exogenous cytokinin activated signalling in the root stem cell niche. Commonly employed auxin reporters DR5 or DR5v2 failed to respond to auxin in barley. However, analysis of putative auxin signalling targets barley PLETHORA1 (HvPLT1) is expressed in a similar pattern as its orthologue AtPLT1 from Arabidopsis, i.e. in the QC and the surrounding cells. Furthermore, the PINFORMED1 (HvPIN1) auxin efflux carrier was found to be expressed in root and shoot meristems, where it polarly localized to the plasma membrane. HvPIN1 expression is negatively regulated by cytokinin and its intracellular localisation is sensitive to brefeldinA (BFA). With this study, we provide the first fluorescent reporter lines as a tool to study auxin and cytokinin signalling and response pathways in barley.
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Affiliation(s)
- Gwendolyn K. Kirschner
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Yvonne Stahl
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Jafargholi Imani
- Research Centre for BioSystems, Land Use and Nutrition (IFZ), Justus Liebig University, Institute of Phytopathology and Applied Zoology, Giessen, Germany
| | - Maria von Korff
- Institute for Plant Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Rüdiger Simon
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University, Düsseldorf, Germany
- * E-mail:
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49
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Jackson CL. Activators and Effectors of the Small G Protein Arf1 in Regulation of Golgi Dynamics During the Cell Division Cycle. Front Cell Dev Biol 2018; 6:29. [PMID: 29632863 PMCID: PMC5879097 DOI: 10.3389/fcell.2018.00029] [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: 11/09/2017] [Accepted: 03/08/2018] [Indexed: 12/23/2022] Open
Abstract
When eukaryotic cells divide, they must faithfully segregate not only the genetic material but also their membrane-bound organelles into each daughter cell. To assure correct partitioning of cellular contents, cells use regulatory mechanisms to verify that each stage of cell division has been correctly accomplished before proceeding to the next step. A great deal is known about mechanisms that regulate chromosome segregation during cell division, but we know much less about the mechanisms by which cellular organelles are partitioned, and how these processes are coordinated. The Golgi apparatus, the central sorting and modification station of the secretory pathway, disassembles during mitosis, a process that depends on Arf1 and its regulators and effectors. Prior to total disassembly, the Golgi ribbon in mammalian cells, composed of alternating cisternal stacks and tubular networks, undergoes fission of the tubular networks to produce individual stacks. Failure to carry out this unlinking leads to cell division arrest at late G2 prior to entering mitosis, an arrest that can be relieved by inhibition of Arf1 activation. The level of active Arf1-GTP drops during mitosis, due to inactivation of the major Arf1 guanine nucleotide exchange factor at the Golgi, GBF1. Expression of constitutively active Arf1 prevents Golgi disassembly, and leads to defects in chromosome segregation and cytokinesis. In this review, we describe recent advances in understanding the functions of Arf1 regulators and effectors in the crosstalk between Golgi structure and cell cycle regulation.
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Affiliation(s)
- Catherine L Jackson
- Institut Jacques Monod, Centre Nationnal de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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Perron A, Nishikawa Y, Iwata J, Shimojo H, Takaya J, Kobayashi K, Imayoshi I, Mbenza NM, Takenoya M, Kageyama R, Kodama Y, Uesugi M. Small-molecule screening yields a compound that inhibits the cancer-associated transcription factor Hes1 via the PHB2 chaperone. J Biol Chem 2018. [PMID: 29523683 DOI: 10.1074/jbc.ra118.002316] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The transcription factor Hes family basic helix-loop-helix transcription factor 1 (Hes1) is a downstream effector of Notch signaling and plays a crucial role in orchestrating developmental processes during the embryonic stage. However, its aberrant signaling in adulthood is linked to the pathogenesis of cancer. In the present study, we report the discovery of small organic molecules (JI051 and JI130) that impair the ability of Hes1 to repress transcription. Hes1 interacts with the transcriptional corepressor transducing-like enhancer of split 1 (TLE1) via an interaction domain comprising two tryptophan residues, prompting us to search a chemical library of 1,800 small molecules enriched for indole-like π-electron-rich pharmacophores for a compound that blocks Hes1-mediated transcriptional repression. This screening identified a lead compound whose extensive chemical modification to improve potency yielded JI051, which inhibited HEK293 cell proliferation with an EC50 of 0.3 μm Unexpectedly, using immunomagnetic isolation and nanoscale LC-MS/MS, we found that JI051 does not bind TLE1 but instead interacts with prohibitin 2 (PHB2), a cancer-associated protein chaperone. We also found that JI051 stabilizes PHB2's interaction with Hes1 outside the nucleus, inducing G2/M cell-cycle arrest. Of note, JI051 dose-dependently reduced cell growth of the human pancreatic cancer cell line MIA PaCa-2, and JI130 treatment significantly reduced tumor volume in a murine pancreatic tumor xenograft model. These results suggest a previously unrecognized role for PHB2 in the regulation of Hes1 and may inform potential strategies for managing pancreatic cancer.
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Affiliation(s)
- Amelie Perron
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011; Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Uji, Kyoto 611-0011
| | | | - Jun Iwata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011
| | - Hiromi Shimojo
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Uji, Kyoto 611-0011; Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Junichiro Takaya
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011
| | - Kumiko Kobayashi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Itaru Imayoshi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan; Graduate School of Biostudies, Kyoto University, Kyoto 606-8507, Japan
| | - Naasson M Mbenza
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011
| | - Mihoko Takenoya
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Uji, Kyoto 611-0011
| | - Ryoichiro Kageyama
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Uji, Kyoto 611-0011; Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Yuzo Kodama
- Department of Gastroenterology and Hepatology, Graduate School of Medicine.
| | - Motonari Uesugi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011; Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Uji, Kyoto 611-0011.
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