1
|
Kwon Y, Kim J, Cho SY, Kang YJ, Lee J, Kwon J, Rhee H, Bauer S, Kim HS, Lee E, Kim HS, Jung JH, Kim H, Kim WK. Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT. Cell Death Differ 2023; 30:2309-2321. [PMID: 37704840 PMCID: PMC10589262 DOI: 10.1038/s41418-023-01220-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/15/2023] Open
Abstract
Gastrointestinal stromal tumors (GISTs) frequently show KIT mutations, accompanied by overexpression and aberrant localization of mutant KIT (MT-KIT). As previously established by multiple studies, including ours, we confirmed that MT-KIT initiates downstream signaling in the Golgi complex. Basic leucine zipper nuclear factor 1 (BLZF1) was identified as a novel MT-KIT-binding partner that tethers MT-KIT to the Golgi complex. Sustained activation of activated transcription factor 6 (ATF6), which belongs to the unfolded protein response (UPR) family, alleviates endoplasmic reticulum (ER) stress by upregulating chaperone expression, including heat shock protein 90 (HSP90), which assists in MT-KIT folding. BLZF1 knockdown and ATF6 inhibition suppressed both imatinib-sensitive and -resistant GIST in vitro. ATF6 inhibitors further showed potent antitumor effects in GIST xenografts, and the effect was enhanced with ER stress-inducing drugs. ATF6 activation was frequently observed in 67% of patients with GIST (n = 42), and was significantly associated with poorer relapse-free survival (P = 0.033). Overall, GIST bypasses ER quality control (QC) and ER stress-mediated cell death via UPR activation and uses the QC-free Golgi to initiate signaling.
Collapse
Affiliation(s)
- Yujin Kwon
- Natural Product Research Center, Korea Institute of Science and Technology (KIST), Gangneung, 25451, South Korea
- Division of Bio-Medical Science & Technology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Jiyoon Kim
- Department of Pharmacology, Department of Biomedicine & Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, 06591, South Korea
| | - Su-Yeon Cho
- Natural Product Research Center, Korea Institute of Science and Technology (KIST), Gangneung, 25451, South Korea
- Division of Bio-Medical Science & Technology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Yoon Jin Kang
- Natural Product Research Center, Korea Institute of Science and Technology (KIST), Gangneung, 25451, South Korea
- Department of Marine Life Sciences, College of Life Science, Gangneung-Wonju National University, Gangneung, 25457, South Korea
| | - Jongsoo Lee
- Department of Urology, Urologic Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Jaeyoung Kwon
- Division of Bio-Medical Science & Technology, University of Science and Technology (UST), Daejeon, 34113, South Korea
- Natural Product Informatics Research Center, Korea Institute of Science and Technology (KIST), Gangneung, 25451, South Korea
| | - Hyungjin Rhee
- Department of Radiology, Research Institute of Radiological Science, Center for Clinical Imaging Data Science, Severance Hospital, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Sebastian Bauer
- Sarcoma Center, West German Cancer Center, University Hospital Essen, University Duisburg-Essen, Germany and German Cancer Consortium (DKTK), Essen, 45141, Germany
| | - Hyung-Sik Kim
- Department of Oral Biochemistry; Dental and Life Science Institute, School of Dentistry, Pusan National University, Yangsan, 50612, South Korea
| | - Esak Lee
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Han Sang Kim
- Division of Medical Oncology, Department of Internal Medicine, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Jae Hung Jung
- Department of Urology, Yonsei University Wonju College of Medicine/Center of Evidence Based Medicine Institute of Convergence Science, Wonju, 26426, South Korea
| | - Hoguen Kim
- Department of Pathology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Won Kyu Kim
- Natural Product Research Center, Korea Institute of Science and Technology (KIST), Gangneung, 25451, South Korea.
- Department of Convergence Medicine, Yonsei University Wonju College of Medicine, Wonju, 26426, South Korea.
| |
Collapse
|
2
|
Thioether-stapled macrocyclic inhibitors of the EH domain of EHD1. Bioorg Med Chem 2017; 26:1206-1211. [PMID: 28951093 DOI: 10.1016/j.bmc.2017.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/31/2017] [Accepted: 09/06/2017] [Indexed: 11/24/2022]
Abstract
Recycling of receptors from the endosomal recycling compartment to the plasma membrane is a critical cellular process, and recycling is particularly important for maintaining invasiveness in solid tumors. In this work, we continue our efforts to inhibit EHD1, a critical adaptor protein involved in receptor recycling. We applied a diversity-oriented macrocyclization approach to produce cyclic peptides with varied conformations, but that each contain a motif that binds to the EH domain of EHD1. Screening these uncovered several new inhibitors for EHD1's EH domain, the most potent of which bound with a Kd of 3.1μM. Several of the most potent inhibitors were tested in a cellular assay that measures extent of vesicle recycling. Inhibiting EHD1 could potentially slow cancer invasiveness and metastasis, and these cyclic peptides represent the most potent inhibitors of EHD1 to date.
Collapse
|
3
|
Szczubiałka K, Pyrć K, Nowakowska M. In search for effective and definitive treatment of herpes simplex virus type 1 (HSV-1) infections. RSC Adv 2016. [DOI: 10.1039/c5ra22896d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Herpes Simplex Virus type 1 (HSV-1) is a nuclear replicating enveloped virus.
Collapse
Affiliation(s)
| | - Krzysztof Pyrć
- Faculty of Biochemistry, Biophysics and Biotechnology
- Jagiellonian University
- 30-387 Kraków
- Poland
| | | |
Collapse
|
4
|
McClain L, Zhi Y, Cheng H, Ghosh A, Piazza P, Yee MB, Kumar S, Milosevic J, Bloom DC, Arav-Boger R, Kinchington PR, Yolken R, Nimgaonkar V, D'Aiuto L. Broad-spectrum non-nucleoside inhibitors of human herpesviruses. Antiviral Res 2015; 121:16-23. [PMID: 26079681 DOI: 10.1016/j.antiviral.2015.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 01/06/2023]
Abstract
Herpesvirus infections cause considerable morbidity and mortality through lifelong recurrent cycles of lytic and latent infection in several tissues, including the human nervous system. Acyclovir (ACV) and its prodrug, the current antivirals of choice for herpes simplex virus (HSV) and, to some extent, varicella zoster virus (VZV) infections are nucleoside analogues that inhibit viral DNA replication. Rising viral resistance and the need for more effective second-line drugs have motivated searches for additional antiviral agents, particularly non-nucleoside based agents. We evaluated the antiviral activity of five compounds with predicted lysosomotropic activity using conventional and human induced pluripotent stem cell-derived neuronal (iPSC-neurons) cultures. Their potency and toxicity were compared with ACV and the lysosomotropic agents chloroquine and bafilomycin A1. Out of five compounds tested, micromolar concentrations of 30N12, 16F19, and 4F17 showed antiviral activity comparable to ACV (50μM) during lytic herpes simplex virus type 1 (HSV-1) infections, reduced viral DNA copy number, and reduced selected HSV-1 protein levels. These compounds also inhibited the reactivation of 'quiescent' HSV-1 infection established in iPSC-neurons, but did not inhibit viral entry into host cells. The same compounds had greater potency than ACV against lytic VZV infection; they also inhibited replication of human cytomegalovirus. The anti-herpetic effects of these non-nucleoside agents merit further evaluation in vivo.
Collapse
Affiliation(s)
- Lora McClain
- Department of Psychiatry, WPIC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yun Zhi
- Department of Psychiatry, WPIC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Hoyee Cheng
- Department of Psychiatry, WPIC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ayantika Ghosh
- Department of Psychiatry, WPIC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Paolo Piazza
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael B Yee
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Santosh Kumar
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jadranka Milosevic
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - David C Bloom
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ravit Arav-Boger
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Paul R Kinchington
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Molecular Genetics & Biochemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Robert Yolken
- Stanley Division of Neurovirology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Vishwajit Nimgaonkar
- Department of Psychiatry, WPIC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Leonardo D'Aiuto
- Department of Psychiatry, WPIC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| |
Collapse
|
5
|
Gee HY, Kim JY, Lee MG. Analysis of conventional and unconventional trafficking of CFTR and other membrane proteins. Methods Mol Biol 2015; 1270:137-54. [PMID: 25702115 DOI: 10.1007/978-1-4939-2309-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a polytopic transmembrane protein that functions as a cAMP-activated anion channel at the apical membrane of epithelial cells. Mutations in CFTR cause cystic fibrosis and are also associated with monosymptomatic diseases in the lung, pancreas, intestines, and vas deferens. Many disease-causing CFTR mutations, including the deletion of a single phenylalanine residue at position 508 (ΔF508-CFTR), result in protein misfolding and trafficking defects. Therefore, intracellular trafficking of wild-type and mutant CFTR has been studied extensively, and results from these studies significantly contribute to our general understanding of mechanisms involved in the cell-surface trafficking of membrane proteins. CFTR is a glycoprotein that undergoes complex N-glycosylation as it passes through Golgi-mediated conventional exocytosis. Interestingly, results from recent studies revealed that CFTR and other membrane proteins can reach the plasma membrane via an unconventional alternative route that bypasses Golgi in specific cellular conditions. Here, we describe methods that have been used to investigate the conventional and unconventional surface trafficking of CFTR. With appropriate modifications, the protocols described in this chapter can also be applied to studies investigating the intracellular trafficking of other plasma membrane proteins.
Collapse
Affiliation(s)
- Heon Yung Gee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, 134 Sinchon-Dong, Seoul, 120-752, Korea
| | | | | |
Collapse
|
6
|
Kamens AJ, Eisert RJ, Corlin T, Baleja JD, Kritzer JA. Structured cyclic peptides that bind the EH domain of EHD1. Biochemistry 2014; 53:4758-60. [PMID: 25014215 PMCID: PMC4116148 DOI: 10.1021/bi500744q] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
EHD1
mediates long-loop recycling of many receptors by forming
signaling complexes using its EH domain. We report the design and
optimization of cyclic peptides as ligands for the EH domain of EHD1.
We demonstrate that the improved affinity from cyclization allows
fluorescence-based screening applications for EH domain inhibitors.
The cyclic peptide is also unusually well-structured in aqueous solution,
as demonstrated using nuclear magnetic resonance-based structural
models. Because few EH domain inhibitors have been described, these
more potent inhibitors will improve our understanding of the roles
of EHD1 in the context of cancer invasion and metastasis.
Collapse
Affiliation(s)
- Alissa J Kamens
- Department of Chemistry, Tufts University , 62 Talbot Avenue, Medford, Massachusetts 02155, United States
| | | | | | | | | |
Collapse
|
7
|
Abstract
It is unclear how unconventional secretion interplays with conventional secretion for the normal maintenance and renewal of membrane structures. The photoreceptor sensory cilium is recognized for fast membrane renewal, for which rhodopsin and peripherin/rds (P/rds) play critical roles. Here, we provide evidence that P/rds is targeted to the cilia by an unconventional secretion pathway. When expressed in ciliated hTERT-RPE1 human cell line, P/rd is localized to cilia. Cilium trafficking of P/rds was sustained even when the Golgi functions, including trans-Golgi-mediated conventional secretion, were inhibited by the small molecules brefeldin A, 30N12, and monensin. The unconventional cilia targeting of P/rds is dependent on COPII-mediated exit from the ER, but appears to be independent of GRASP55-mediated secretion. The regions in the C-terminal tail of P/rds are essential for this unconventional trafficking. In the absence of the region required for cilia targeting, P/rds was prohibited from entering the secretory pathways and was retained in the Golgi apparatus. A region essential for this Golgi retention was also found in the C-terminal tail of P/rds and supported the cilia targeting of P/rds mediated by unconventional secretion. In ciliated cells, including bovine and Xenopus laevis rod photoreceptors, P/rds was robustly sensitive to endoglycosidase H, which is consistent with its bypassing the medial Golgi and traversing the unconventional secretory pathway. Because rhodopsin is known to traffic through conventional secretion, this study of P/rds suggests that both conventional secretion and unconventional secretion need to cooperate for the renewal of the photoreceptor sensory cilium.
Collapse
|
8
|
Ivanov AI. Pharmacological inhibitors of exocytosis and endocytosis: novel bullets for old targets. Methods Mol Biol 2014; 1174:3-18. [PMID: 24947371 DOI: 10.1007/978-1-4939-0944-5_1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Pharmacological inhibitors of vesicle trafficking possess great promise as valuable analytical tools for the study of a variety of biological processes and as potential therapeutic agents to fight microbial infections and cancer. However, many commonly used trafficking inhibitors are characterized by poor selectivity that diminishes their use in solving basic problems of cell biology or drug development. Recent high-throughput chemical screens intensified the search for novel modulators of vesicle trafficking, and successfully identified a number of small molecules that inhibit exocytosis and endocytosis in different types of mammalian cells. This chapter provides a systematic overview of recently discovered inhibitors of vesicle trafficking. It describes cellular effects and mechanisms of action of novel inhibitors of exocytosis and endocytosis. Furthermore, it pays special attention to the selectivity and possible off-target effects of these inhibitors.
Collapse
Affiliation(s)
- Andrei I Ivanov
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine, Virginia Commonwealth University, Goodwin Laboratory, 401 College Street, 980035, Richmond, VA, 23298, USA,
| |
Collapse
|
9
|
Guo X, Zhang Z, Zhang F, Tao Y, An P, Wu Q, Wang CY, Knutson MD, Wang F. Fine-mapping and genetic analysis of the loci affecting hepatic iron overload in mice. PLoS One 2013; 8:e63280. [PMID: 23675470 PMCID: PMC3651197 DOI: 10.1371/journal.pone.0063280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/29/2013] [Indexed: 12/12/2022] Open
Abstract
The liver, as the major organ for iron storage and production of hepcidin, plays pivotal roles in maintaining mammalian iron homeostasis. A previous study showed that Quantitative Trait Loci (QTLs) on chromosome 7 (Chr7) and 16 (Chr16) may control hepatic non-heme iron overload in an F2 intercross derived from C57BL/6J (B6) and SWR/J (SWR) mice. In this study, we aimed to validate the existence of these loci and identify the genes responsible for the phenotypic variations by generating congenic mice carrying SWR chromosome segments expanding these QTLs (D7Mit68-D7Mit71 and D16Mit125-D16Mit185, respectively). We excluded involvement of Chr7 based on the lack of iron accumulation in congenic mice. In contrast, liver iron accumulation was observed in Chr16 congenic mice. Through use of a series of subcongenic murine lines the interval on Chr16 was further fine-mapped to a 0.8 Mb segment spanning 11 genes. We found that the mRNA expression pattern in the liver remained unchanged for all 11 genes tested. Most importantly, we detected 4 missense mutations in 3 candidate genes including Sidt1 (P172R), Spice1(R708S), Boc (Q1051R) and Boc (S450-insertion in B6 allele) in the liver of SWR homozygous congenic mice. To further delineate potential modifier gene(s), we reconstituted seven candidate genes, Sidt1, Boc, Zdhhc23, Gramd1c, Atp6v1a, Naa50 and Gtpbp8, in mouse liver through hydrodynamic transfection. However, we were unable to detect significant changes in liver iron levels upon reconstitution of these candidate genes. Taken together, our work provides strong genetic evidence of the existence of iron modifiers on Chr16. Moreover, we were able to delineate the phenotypically responsible region to a 0.8 Mb region containing 11 coding genes, 3 of which harbor missense mutations, using a series of congenic mice.
Collapse
Affiliation(s)
- Xin Guo
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Zhuzhen Zhang
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Fan Zhang
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Yunlong Tao
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Peng An
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Qian Wu
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Chia-Yu Wang
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, Florida, United States of America
| | - Mitchell D. Knutson
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, Florida, United States of America
| | - Fudi Wang
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
- * E-mail:
| |
Collapse
|
10
|
Mishev K, Dejonghe W, Russinova E. Small Molecules for Dissecting Endomembrane Trafficking: A Cross-Systems View. ACTA ACUST UNITED AC 2013; 20:475-86. [DOI: 10.1016/j.chembiol.2013.03.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 01/31/2023]
|
11
|
Abstract
Elucidating the molecular basis for the regulation of iron uptake, storage, and distribution is necessary to understand iron homeostasis. Pharmacological tools are emerging to identify and distinguish among different iron transport pathways. Stimulatory or inhibitory small molecules with effects on iron uptake can help characterize the mechanistic elements of iron transport and the roles of the transporters involved in these processes. In particular, iron chelators can serve as potential pharmacological tools to alleviate diseases of iron overload. This review focuses on the pharmacology of iron transport, introducing iron transport membrane proteins and known inhibitors.
Collapse
Affiliation(s)
- Shaina L Byrne
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
| | | | | |
Collapse
|
12
|
von Kleist L, Haucke V. At the crossroads of chemistry and cell biology: inhibiting membrane traffic by small molecules. Traffic 2011; 13:495-504. [PMID: 21951680 DOI: 10.1111/j.1600-0854.2011.01292.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 09/22/2011] [Accepted: 09/22/2011] [Indexed: 01/12/2023]
Abstract
Intracellular membrane traffic regulates cell physiology at multiple levels ranging from cell growth and development to the function of the nervous and immune systems. Multiple endocytic routes are used by distinct cargoes including ligands bound to their receptors but also viruses and pathogens to gain access to the cell interior. Within the endosomal system, proteins and lipids are sorted for degradation or recycling allowing cells to dynamically respond to environmental signals and to regulate cell shape and morphology. Some receptors or toxins are sorted along the retrograde pathway from endosomes to the Golgi complex, where they intersect with secretory cargo destined for exocytosis. Genetic manipulations of these pathways frequently cause problems with regard to data interpretation as the resulting phenotypes may be indirect consequences resulting from perturbation of multiple steps or trafficking routes. Hence, novel approaches are needed to acutely and reversibly perturb intracellular membrane traffic, e.g., by small molecule inhibitors. Such drugs may also be pharmacologically important as they offer new avenues to fight human diseases. Here, we provide an overview of the small molecules available to interfere with intracellular membrane traffic and outline strategies for future research.
Collapse
Affiliation(s)
- Lisa von Kleist
- Department of Membrane Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany
| | | |
Collapse
|
13
|
Genome-wide analysis reveals the vacuolar pH-stat of Saccharomyces cerevisiae. PLoS One 2011; 6:e17619. [PMID: 21423800 PMCID: PMC3056714 DOI: 10.1371/journal.pone.0017619] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 02/02/2011] [Indexed: 11/26/2022] Open
Abstract
Protons, the smallest and most ubiquitous of ions, are central to physiological processes. Transmembrane proton gradients drive ATP synthesis, metabolite transport, receptor recycling and vesicle trafficking, while compartmental pH controls enzyme function. Despite this fundamental importance, the mechanisms underlying pH homeostasis are not entirely accounted for in any organelle or organism. We undertook a genome-wide survey of vacuole pH (pHv) in 4,606 single-gene deletion mutants of Saccharomyces cerevisiae under control, acid and alkali stress conditions to reveal the vacuolar pH-stat. Median pHv (5.27±0.13) was resistant to acid stress (5.28±0.14) but shifted significantly in response to alkali stress (5.83±0.13). Of 107 mutants that displayed aberrant pHv under more than one external pH condition, functional categories of transporters, membrane biogenesis and trafficking machinery were significantly enriched. Phospholipid flippases, encoded by the family of P4-type ATPases, emerged as pH regulators, as did the yeast ortholog of Niemann Pick Type C protein, implicated in sterol trafficking. An independent genetic screen revealed that correction of pHv dysregulation in a neo1ts mutant restored viability whereas cholesterol accumulation in human NPC1−/− fibroblasts diminished upon treatment with a proton ionophore. Furthermore, while it is established that lumenal pH affects trafficking, this study revealed a reciprocal link with many mutants defective in anterograde pathways being hyperacidic and retrograde pathway mutants with alkaline vacuoles. In these and other examples, pH perturbations emerge as a hitherto unrecognized phenotype that may contribute to the cellular basis of disease and offer potential therapeutic intervention through pH modulation.
Collapse
|
14
|
Guetzoyan LJ, Spooner RA, Boal F, Stephens DJ, Lord JM, Roberts LM, Clarkson GJ. Fine tuning Exo2, a small molecule inhibitor of secretion and retrograde trafficking pathways in mammalian cells. MOLECULAR BIOSYSTEMS 2010; 6:2030-8. [DOI: 10.1039/c0mb00035c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
15
|
Mohammad-Panah R, Wellhauser L, Steinberg BE, Wang Y, Huan LJ, Liu XD, Bear CE. An essential role for ClC-4 in transferrin receptor function revealed in studies of fibroblasts derived from Clcn4-null mice. J Cell Sci 2009; 122:1229-37. [DOI: 10.1242/jcs.037317] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
ClC-4 is closely related to ClC-5, a member of the ClC family of transporters and channels. Unlike ClC-5, for which a role in the regulation of endosomal function was well established, the cellular function of ClC-4 was uncertain. In the present study, we tested for a specific role for ClC-4 in recycling endosomes by comparing transferrin (Tfn) receptor function in primary cell lines generated from ClC-4-null mice and their wild-type siblings. We found that endosomal pH is relatively alkaline and receptor-mediated uptake of Tfn is reduced in ClC-4-null fibroblasts. Surprisingly, this reduction in Tfn uptake occurs, despite a minor increase in the total surface expression of the Tfn receptor in ClC-4-null fibroblasts. As impaired Tfn uptake by ClC-4-null fibroblasts could be rescued to wild-type levels by addition of the iron chelator: desoxiferramine, the primary defect in these cells is related to the failure of iron to dissociate from Tfn, a pH-dependent event in endosomes that precedes the dissociation of Tfn from its receptor at the cell surface. Interestingly, ClC-4 depletion had no effect on epidermal growth factor receptor (EGFR) trafficking to lysosomes for degradation pointing to its specific role in recycling endosomes. These observations provide direct evidence supporting an essential role for ClC-4 in the modulation of Tfn receptor accessibility at the cell surface through its role in endosomal acidification.
Collapse
Affiliation(s)
- Raha Mohammad-Panah
- Programme in Molecular Structure and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
| | - Leigh Wellhauser
- Programme in Molecular Structure and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Canada
| | - Benjamin E. Steinberg
- Programme in Cell Biology, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
| | - Yanchun Wang
- Programme in Molecular Structure and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
| | - Ling Jun Huan
- Programme in Molecular Structure and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
| | - Xiang-Dong Liu
- Department of Genetics, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
| | - Christine E. Bear
- Programme in Molecular Structure and Function, Hospital for Sick Children, 555 University Avenue, Toronto, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Canada
| |
Collapse
|
16
|
Ohgaki R, Fukura N, Matsushita M, Mitsui K, Kanazawa H. Cell surface levels of organellar Na+/H+ exchanger isoform 6 are regulated by interaction with RACK1. J Biol Chem 2007; 283:4417-29. [PMID: 18057008 DOI: 10.1074/jbc.m705146200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammalian cells, four Na(+)/H(+) exchangers (NHE6 - NHE9) are localized to intracellular compartments. NHE6 and NHE9 are predominantly localized to sorting and recycling endosomes, NHE7 to the trans-Golgi network, and NHE8 to the mid-trans-Golgi stacks. The unique localization of NHEs may contribute to establishing organelle-specific pH values and ion homeostasis in cells. Mechanisms underlying the regulation and targeting of organellar NHEs are largely unknown. We identified an interaction between NHE9 and RACK1 (receptor for activated C kinase 1), a cytoplasmic scaffold protein, by yeast two-hybrid screening using the NHE9 C terminus as bait. The NHE9 C terminus is exposed to the cytoplasm, verifying that the interaction is topologically possible. The binding region was further delineated to the central region of the NHE9 C terminus. RACK1 also bound NHE6 and NHE7, but not NHE8, in vitro. Endogenous association between NHE6 and RACK1 was confirmed by co-immunoprecipitation and co-localization in HeLa cells. The luminal pH of the recycling endosome was elevated in RACK1 knockdown cells, accompanied by a decrease in the amount of NHE6 on the cell surface, although the total level of NHE6 was not significantly altered. These results indicate that RACK1 plays a role in regulating the distribution of NHE6 between endosomes and the plasma membrane and contributes to maintaining luminal pH of the endocytic recycling compartments.
Collapse
Affiliation(s)
- Ryuichi Ohgaki
- Department of Biological Science, Graduate School of Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | | | | | | | | |
Collapse
|
17
|
Affiliation(s)
- Daniel P Walsh
- Department of Chemistry, New York University, New York, New York 10003, USA
| | | |
Collapse
|
18
|
Komarov AM, Hall JM, Chmielinska JJ, Weglicki WB. Iron Uptake and Release by Macrophages is Sensitive to Propranolol. Mol Cell Biochem 2006; 288:213-7. [PMID: 16718379 DOI: 10.1007/s11010-006-9138-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Accepted: 01/17/2006] [Indexed: 11/29/2022]
Abstract
In this study we have tested the effects of d-propranolol (D-Pro) on the iron uptake, iron release and oxidative response of iron-loaded cells in a cellular model of iron-overload using isolated rat peritoneal macrophages incubated with iron-dextran (Fe-D). Pretreatment of macrophages with D-Pro (5-200 microM) prior to Fe-D exposure decreased the cellular iron content and partially prevented iron release from latex-activated macrophages. Release of reactive oxygen species from activated cells was detected by dichlorodihydrofluorescein (DCDHF, 5 microM) oxidation. We found that loading cells with Fe-D increased their response to latex, which was prevented by the lysosomotropic antioxidant agent D-Pro (10 microM).
Collapse
Affiliation(s)
- Andrei M Komarov
- Division of Experimental Medicine, Departments of Biochemistry & Molecular Biology, The George Washington University Medical Center, 2300 Eye St., NW, Ross Hall, Rm. 441A, Washington, DC 20037, USA.
| | | | | | | |
Collapse
|
19
|
Phillips CI, Bogyo M. Proteomics meets microbiology: technical advances in the global mapping of protein expression and function. Cell Microbiol 2005; 7:1061-76. [PMID: 16008574 DOI: 10.1111/j.1462-5822.2005.00554.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The availability of complete genome sequences for a large number of pathogenic organisms has opened the door for large-scale proteomic studies to dissect both protein expression/regulation and function. This review highlights key proteomic methods including two-dimensional gel electrophoresis, reference mapping, protein expression profiling and recent advances in gel-free separation techniques that have made a significant impact on the resolution of complex proteomes. In addition, we highlight recent developments in the field of chemical proteomics, a branch of proteomics aimed at functionally profiling a proteome. These techniques include the development of activity-based probes and activity-based protein profiling methods as well as the use of synthetic small molecule libraries to screen for pharmacological tools to perturb basic biological processes. This review will focus on the applications of these technologies to the field of microbiology.
Collapse
Affiliation(s)
- Carolyn I Phillips
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5324, USA
| | | |
Collapse
|
20
|
Abstract
Chemical genetics is an emerging approach for studying biological systems using chemical tools. This strategy aims to reveal the macromolecules responsible for regulating biological systems; thus, the approach shares much in common with genetics. In both strategies, one must (a) develop an assay that reports on a biological process of interest, (b) perturb this process systematically (with mutations or small molecules), and (c) determine the target of each perturbation to reveal macromolecules (i.e., proteins and genes) regulating the process of interest. In this review, we discuss advances and challenges in this field that have emerged over the past four years. Several technologies have converged, raising the hope that it may be possible to systematically apply chemical probes to biological processes.
Collapse
Affiliation(s)
- Inese Smukste
- Department of Biological Sciences and Department of Chemistry, Columbia University, Fairchild Center, New York, New York 10027, USA
| | | |
Collapse
|
21
|
Abstract
The crucial role of lipids in cell, tissue and organ physiology is demonstrated by a large number of genetic studies and by many human diseases that involve the disruption of lipid metabolic enzymes and pathways. Examples of such diseases include cancer, diabetes, as well as neurodegenerative and infectious diseases. So far, the explosion of information in the fields of genomics and proteomics has not been matched by a corresponding advancement of knowledge in the field of lipids, which is largely due to the complexity of lipids and the lack of powerful tools for their analysis. Novel analytical approaches--in particular, liquid chromatography and mass spectrometry--for systems-level analysis of lipids and their interacting partners (lipidomics) now make this field a promising area of biomedical research, with a variety of applications in drug and biomarker development.
Collapse
Affiliation(s)
- Markus R Wenk
- Department of Biochemistry, National University of Singapore, 8 Medical Drive, MD7, Singapore 117597.
| |
Collapse
|
22
|
Brett CL, Tukaye DN, Mukherjee S, Rao R. The yeast endosomal Na+K+/H+ exchanger Nhx1 regulates cellular pH to control vesicle trafficking. Mol Biol Cell 2005; 16:1396-405. [PMID: 15635088 PMCID: PMC551501 DOI: 10.1091/mbc.e04-11-0999] [Citation(s) in RCA: 237] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The relationship between endosomal pH and function is well documented in viral entry, endosomal maturation, receptor recycling, and vesicle targeting within the endocytic pathway. However, specific molecular mechanisms that either sense or regulate luminal pH to mediate these processes have not been identified. Herein we describe the use of novel, compartment-specific pH indicators to demonstrate that yeast Nhx1, an endosomal member of the ubiquitous NHE family of Na+/H+ exchangers, regulates luminal and cytoplasmic pH to control vesicle trafficking out of the endosome. Loss of Nhx1 confers growth sensitivity to low pH stress, and concomitant acidification and trafficking defects, which can be alleviated by weak bases. Conversely, weak acids cause wild-type yeast to present nhx1Delta trafficking phenotypes. Finally, we report that Nhx1 transports K+ in addition to Na+, suggesting that a single mechanism may responsible for both pH and K+-dependent endosomal processes. This presents the newly defined family of eukaryotic endosomal NHE as novel targets for pharmacological inhibition to alleviate pathological states associated with organellar alkalinization.
Collapse
Affiliation(s)
- Christopher L Brett
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | | |
Collapse
|