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Bao M, Hua X, Chen X, An T, Mo H, Sun Z, Tao M, Yue G, Song J. PICALM Regulating the Generation of Amyloid β-Peptide to Promote Anthracycline-Induced Cardiotoxicity. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401945. [PMID: 38935046 PMCID: PMC11348153 DOI: 10.1002/advs.202401945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/22/2024] [Indexed: 06/28/2024]
Abstract
Anthracyclines are chemotherapeutic drugs used to treat solid and hematologic malignancies. However, life-threatening cardiotoxicity, with cardiac dilation and heart failure, is a drawback. A combination of in vivo for single cell/nucleus RNA sequencing and in vitro approaches is used to elucidate the underlying mechanism. Genetic depletion and pharmacological blocking peptides on phosphatidylinositol binding clathrin assembly (PICALM) are used to evaluate the role of PICALM in doxorubicin-induced cardiotoxicity in vivo. Human heart tissue samples are used for verification. Patients with end-stage heart failure and chemotherapy-induced cardiotoxicity have thinner cell membranes compared to healthy controls do. Using the doxorubicin-induced cardiotoxicity mice model, it is possible to replicate the corresponding phenotype in patients. Cellular changes in doxorubicin-induced cardiotoxicity in mice, especially in cardiomyocytes, are identified using single cell/nucleus RNA sequencing. Picalm expression is upregulated only in cardiomyocytes with doxorubicin-induced cardiotoxicity. Amyloid β-peptide production is also increased after doxorubicin treatment, which leads to a greater increase in the membrane permeability of cardiomyocytes. Genetic depletion and pharmacological blocking peptides on Picalm reduce the generation of amyloid β-peptide. This alleviates the doxorubicin-induced cardiotoxicity in vitro and in vivo. In human heart tissue samples of patients with chemotherapy-induced cardiotoxicity, PICALM, and amyloid β-peptide are elevated as well.
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Affiliation(s)
- Mengni Bao
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant MaterialsAnimal Experimental CentreFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100037China
- State Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- Shenzhen Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical SciencesShenzhen518057China
| | - Xiumeng Hua
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant MaterialsAnimal Experimental CentreFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100037China
- State Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- Department of Cardiovascular SurgeryFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- The Cardiomyopathy Research GroupFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
| | - Xiao Chen
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant MaterialsAnimal Experimental CentreFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100037China
- State Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- Department of Cardiovascular SurgeryFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- The Cardiomyopathy Research GroupFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
| | - Tao An
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant MaterialsAnimal Experimental CentreFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100037China
- Department of CardiologyFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
| | - Han Mo
- Shenzhen Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical SciencesShenzhen518057China
| | - Zhe Sun
- Shenzhen Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical SciencesShenzhen518057China
| | - Menghao Tao
- State Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
| | - Guangxin Yue
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant MaterialsAnimal Experimental CentreFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100037China
| | - Jiangping Song
- Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant MaterialsAnimal Experimental CentreFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100037China
- State Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- Shenzhen Key Laboratory of Cardiovascular DiseaseFuwai HospitalChinese Academy of Medical SciencesShenzhen518057China
- Department of Cardiovascular SurgeryFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
- The Cardiomyopathy Research GroupFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing10037China
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Lee J, Lee H, Lee H, Shin M, Shin MG, Seo J, Lee EJ, Park SA, Park S. ANKS1A regulates LDL receptor-related protein 1 (LRP1)-mediated cerebrovascular clearance in brain endothelial cells. Nat Commun 2023; 14:8463. [PMID: 38123547 PMCID: PMC10733300 DOI: 10.1038/s41467-023-44319-3] [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: 11/10/2022] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
Brain endothelial LDL receptor-related protein 1 (LRP1) is involved in the clearance of Aβ peptides across the blood-brain barrier (BBB). Here we show that endothelial deficiency of ankyrin repeat and SAM domain containing 1 A (ANKS1A) reduces both the cell surface levels of LRP1 and the Aβ clearance across the BBB. Association of ANKS1A with the NPXY motifs of LRP1 facilitates the transport of LRP1 from the endoplasmic reticulum toward the cell surface. ANKS1A deficiency in an Alzheimer's disease mouse model results in exacerbated Aβ pathology followed by cognitive impairments. These deficits are reversible by gene therapy with brain endothelial-specific ANKS1A. In addition, human induced pluripotent stem cell-derived BBBs (iBBBs) were generated from endothelial cells lacking ANKS1A or carrying the rs6930932 variant. Those iBBBs exhibit both reduced cell surface LRP1 and impaired Aβ clearance. Thus, our findings demonstrate that ANKS1A regulates LRP1-mediated Aβ clearance across the BBB.
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Affiliation(s)
- Jiyeon Lee
- Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Korea
| | - Haeryung Lee
- Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Korea
| | - Hyein Lee
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, 42988, Korea
| | - Miram Shin
- Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Korea
| | - Min-Gi Shin
- Department of Brain Science, Ajou University School of Medicine, Suwon, 16499, Korea
| | - Jinsoo Seo
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, 42988, Korea
| | - Eun Jeong Lee
- Department of Brain Science, Ajou University School of Medicine, Suwon, 16499, Korea
| | - Sun Ah Park
- Lab for Neurodegenerative Dementia, Department of Anatomy, and Department of Neurology, Ajou University School of Medicine, Suwon, 16499, Korea
| | - Soochul Park
- Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Korea.
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Kisler K, Sagare AP, Lazic D, Bazzi S, Lawson E, Hsu CJ, Wang Y, Ramanathan A, Nelson AR, Zhao Z, Zlokovic BV. Anti-malaria drug artesunate prevents development of amyloid-β pathology in mice by upregulating PICALM at the blood-brain barrier. Mol Neurodegener 2023; 18:7. [PMID: 36707892 PMCID: PMC9883925 DOI: 10.1186/s13024-023-00597-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/13/2023] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND PICALM is one of the most significant susceptibility factors for Alzheimer's disease (AD). In humans and mice, PICALM is highly expressed in brain endothelium. PICALM endothelial levels are reduced in AD brains. PICALM controls several steps in Aβ transcytosis across the blood-brain barrier (BBB). Its loss from brain endothelium in mice diminishes Aβ clearance at the BBB, which worsens Aβ pathology, but is reversible by endothelial PICALM re-expression. Thus, increasing PICALM at the BBB holds potential to slow down development of Aβ pathology. METHODS To identify a drug that could increase PICALM expression, we screened a library of 2007 FDA-approved drugs in HEK293t cells expressing luciferase driven by a human PICALM promoter, followed by a secondary mRNA screen in human Eahy926 endothelial cell line. In vivo studies with the lead hit were carried out in Picalm-deficient (Picalm+/-) mice, Picalm+/-; 5XFAD mice and Picalmlox/lox; Cdh5-Cre; 5XFAD mice with endothelial-specific Picalm knockout. We studied PICALM expression at the BBB, Aβ pathology and clearance from brain to blood, cerebral blood flow (CBF) responses, BBB integrity and behavior. RESULTS Our screen identified anti-malaria drug artesunate as the lead hit. Artesunate elevated PICALM mRNA and protein levels in Eahy926 endothelial cells and in vivo in brain capillaries of Picalm+/- mice by 2-3-fold. Artesunate treatment (32 mg/kg/day for 2 months) of 3-month old Picalm+/-; 5XFAD mice compared to vehicle increased brain capillary PICALM levels by 2-fold, and reduced Aβ42 and Aβ40 levels and Aβ and thioflavin S-load in the cortex and hippocampus, and vascular Aβ load by 34-51%. Artesunate also increased circulating Aβ42 and Aβ40 levels by 2-fold confirming accelerated Aβ clearance from brain to blood. Consistent with reduced Aβ pathology, treatment of Picalm+/-; 5XFAD mice with artesunate improved CBF responses, BBB integrity and behavior on novel object location and recognition, burrowing and nesting. Endothelial-specific knockout of PICALM abolished all beneficial effects of artesunate in 5XFAD mice indicating that endothelial PICALM is required for its therapeutic effects. CONCLUSIONS Artesunate increases PICALM levels and Aβ clearance at the BBB which prevents development of Aβ pathology and functional deficits in mice and holds potential for translation to human AD.
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Affiliation(s)
- Kassandra Kisler
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Abhay P. Sagare
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Divna Lazic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Sam Bazzi
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Erica Lawson
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Ching-Ju Hsu
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Yaoming Wang
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Anita Ramanathan
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Amy R. Nelson
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Zhen Zhao
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
| | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA 90089 USA
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Bhattacharya A, Freedman AN, Avula V, Harris R, Liu W, Pan C, Lusis AJ, Joseph RM, Smeester L, Hartwell HJ, Kuban KCK, Marsit CJ, Li Y, O'Shea TM, Fry RC, Santos HP. Placental genomics mediates genetic associations with complex health traits and disease. Nat Commun 2022; 13:706. [PMID: 35121757 PMCID: PMC8817049 DOI: 10.1038/s41467-022-28365-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/15/2021] [Indexed: 01/09/2023] Open
Abstract
As the master regulator in utero, the placenta is core to the Developmental Origins of Health and Disease (DOHaD) hypothesis but is historically understudied. To identify placental gene-trait associations (GTAs) across the life course, we perform distal mediator-enriched transcriptome-wide association studies (TWAS) for 40 traits, integrating placental multi-omics from the Extremely Low Gestational Age Newborn Study. At [Formula: see text], we detect 248 GTAs, mostly for neonatal and metabolic traits, across 176 genes, enriched for cell growth and immunological pathways. In aggregate, genetic effects mediated by placental expression significantly explain 4 early-life traits but no later-in-life traits. 89 GTAs show significant mediation through distal genetic variants, identifying hypotheses for distal regulation of GTAs. Investigation of one hypothesis in human placenta-derived choriocarcinoma cells reveal that knockdown of mediator gene EPS15 upregulates predicted targets SPATA13 and FAM214A, both associated with waist-hip ratio in TWAS, and multiple genes involved in metabolic pathways. These results suggest profound health impacts of placental genomic regulation in developmental programming across the life course.
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Affiliation(s)
- Arjun Bhattacharya
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
- Institute for Quantitative and Computational Biosciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
| | - Anastasia N Freedman
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Vennela Avula
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Rebeca Harris
- Biobehavioral Laboratory, School of Nursing, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Weifang Liu
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Calvin Pan
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Aldons J Lusis
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - Robert M Joseph
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Lisa Smeester
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
- Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Hadley J Hartwell
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Karl C K Kuban
- Department of Pediatrics, Division of Pediatric Neurology, Boston University Medical Center, Boston, MA, 02118, USA
| | - Carmen J Marsit
- Gangarosa Department of Environmental Health, Rollins School of Public Health Emory University, Atlanta, GA, 30322, USA
| | - Yun Li
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, 27514, USA
- Department of Computer Science, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - T Michael O'Shea
- Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Rebecca C Fry
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA.
- Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA.
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina, Chapel Hill, NC, 27514, USA.
| | - Hudson P Santos
- Biobehavioral Laboratory, School of Nursing, University of North Carolina, Chapel Hill, NC, 27514, USA.
- Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27514, USA.
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Rópolo AS, Feliziani C, Touz MC. Unusual proteins in Giardia duodenalis and their role in survival. ADVANCES IN PARASITOLOGY 2019; 106:1-50. [PMID: 31630755 DOI: 10.1016/bs.apar.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The capacity of the parasite Giardia duodenalis to perform complex functions with minimal amounts of proteins and organelles has attracted increasing numbers of scientists worldwide, trying to explain how this parasite adapts to internal and external changes to survive. One explanation could be that G. duodenalis evolved from a structurally complex ancestor by reductive evolution, resulting in adaptation to its parasitic lifestyle. Reductive evolution involves the loss of genes, organelles, and functions that commonly occur in many parasites, by which the host renders some structures and functions redundant. However, there is increasing data that Giardia possesses proteins able to perform more than one function. During recent decades, the concept of moonlighting was described for multitasking proteins, which involves only proteins with an extra independent function(s). In this chapter, we provide an overview of unusual proteins in Giardia that present multifunctional properties depending on the location and/or parasite requirement. We also discuss experimental evidence that may allow some giardial proteins to be classified as moonlighting proteins by examining the properties of moonlighting proteins in general. Up to date, Giardia does not seem to require the numerous redundant proteins present in other organisms to accomplish its normal functions, and thus this parasite may be an appropriate model for understanding different aspects of moonlighting proteins, which may be helpful in the design of drug targets.
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Affiliation(s)
- Andrea S Rópolo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Constanza Feliziani
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María C Touz
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.
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Intersectin goes nuclear: secret life of an endocytic protein. Biochem J 2018; 475:1455-1472. [PMID: 29599122 DOI: 10.1042/bcj20170897] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/22/2018] [Accepted: 03/26/2018] [Indexed: 01/22/2023]
Abstract
Intersectin 1-short (ITSN1-s) is a 1220 amino acid ubiquitously expressed scaffold protein presenting a multidomain structure that allows to spatiotemporally regulate the functional interaction of a plethora of proteins. Besides its well-established role in endocytosis, ITSN1-s is involved in the regulation of cell signaling and is implicated in tumorigenesis processes, although the signaling pathways involved are still poorly understood. Here, we identify ITSN1-s as a nucleocytoplasmic trafficking protein. We show that, by binding to importin (IMP)α, a small fraction of ITSN1-s localizes in the cell nucleus at the steady state, where it preferentially associates with the nuclear envelope and interacts with lamin A/C. However, upon pharmacological ablation of chromosome region maintenance 1 (CRM-1)-dependent nuclear export pathway, the protein accumulates into the nucleus, thus revealing its moonlighting nature. Analysis of deletion mutants revealed that the coiled coil (CC) and Src homology (SH3) regions play the major role in its nucleocytoplasmic shuttling. While no evidence of nuclear localization signal (NLS) was detected in the CC region, a functional bipartite NLS was identified within the SH3D region of ITSN1-s (RKKNPGGWWEGELQARGKKRQIGW-1127), capable of conferring energy-dependent nuclear accumulation to reporter proteins and whose mutational ablation affects nuclear import of the whole SH3 region. Thus, ITSN1-s is an endocytic protein, which shuttles between the nucleus and the cytoplasm in a CRM-1- and IMPα-dependent fashion.
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Giovannone AJ, Winterstein C, Bhattaram P, Reales E, Low SH, Baggs JE, Xu M, Lalli MA, Hogenesch JB, Weimbs T. Soluble syntaxin 3 functions as a transcriptional regulator. J Biol Chem 2018; 293:5478-5491. [PMID: 29475951 DOI: 10.1074/jbc.ra117.000874] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/20/2018] [Indexed: 01/06/2023] Open
Abstract
Syntaxins are a conserved family of SNARE proteins and contain C-terminal transmembrane anchors required for their membrane fusion activity. Here we show that Stx3 (syntaxin 3) unexpectedly also functions as a nuclear regulator of gene expression. We found that alternative splicing creates a soluble isoform that we termed Stx3S, lacking the transmembrane anchor. Soluble Stx3S binds to the nuclear import factor RanBP5 (RAN-binding protein 5), targets to the nucleus, and interacts physically and functionally with several transcription factors, including ETV4 (ETS variant 4) and ATF2 (activating transcription factor 2). Stx3S is differentially expressed in normal human tissues, during epithelial cell polarization, and in breast cancer versus normal breast tissue. Inhibition of endogenous Stx3S expression alters the expression of cancer-associated genes and promotes cell proliferation. Similar nuclear-targeted, soluble forms of other syntaxins were identified, suggesting that nuclear signaling is a conserved, novel function common among these membrane-trafficking proteins.
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Affiliation(s)
- Adrian J Giovannone
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Christine Winterstein
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Pallavi Bhattaram
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Elena Reales
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Seng Hui Low
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Julie E Baggs
- the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Mimi Xu
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Matthew A Lalli
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - John B Hogenesch
- the Center for Chronobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Thomas Weimbs
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625,
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A Novel β-adaptin/c-Myc Complex Formation Modulated by Oxidative Stress in the Control of the Cell Cycle in Macrophages and its Implication in Atherogenesis. Sci Rep 2017; 7:13442. [PMID: 29044181 PMCID: PMC5647411 DOI: 10.1038/s41598-017-13880-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 10/02/2017] [Indexed: 02/07/2023] Open
Abstract
Our study tested the proposal that c-Myc activation in macrophages is differentially carried out dependent on the intracellular oxidative state of cells and potentially associated to the process of atherogenesis. Under our experimental conditions, the generation of reactive oxygen species carried out by the presence of oxidized low density lipoproteins (oxLDL) or Gram negative bacterial lipopolysaccharides (LPS) modifies the expression of cellular adhesion molecules such as c-Abl, calcium transport proteins such as the plasma membrane Ca2+-ATPase (PMCA), CD47, procaspase-7, CASP7, CHOP, transcriptional activators such as c-Jun and c-Myc and molecules that participate in the process of endocytosis like α- and β-adaptin. We present the first evidence showing that a state of oxidative stress alters c-Myc-dependent activity pathways in macrophages through binding to molecules such as β-adaptin promoting the reversible formation of a complex that presents the ability to regulate the development of the cell cycle. We propose that the subtle regulation carried out through the formation of this c-Myc/β-adaptin complex when cells change from a normal physiological condition to a state of oxidative stress, represents a defense mechanism against the deleterious effects caused by the loss of cell homeostasis.
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Feliziani C, Touz MC. To a better understanding of the giardial ENTH protein function. Biosci Trends 2017; 11:115-119. [PMID: 28123147 DOI: 10.5582/bst.2016.01225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Epsin N-terminal homology (ENTH) domains are present at the N-terminus of either the epsin or epsin-related (epsinR) proteins. These proteins have been involved in clathrin-mediated trafficking and are critical for membrane deformation at the site of vesicle budding. While more than one type of these proteins have been described in many eukaryotic cells, the protozoa parasite Giardia lamblia contains only one member of this ENTH-protein family. In the last two years, four works have been published showing that this giardial protein might play diverse functions. This commentary gives a brief overview on the current status of the particular characteristics and functions of this unique protein.
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Affiliation(s)
- Constanza Feliziani
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC - CONICET - Universidad Nacional de Córdoba
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Thomas RS, Henson A, Gerrish A, Jones L, Williams J, Kidd EJ. Decreasing the expression of PICALM reduces endocytosis and the activity of β-secretase: implications for Alzheimer's disease. BMC Neurosci 2016; 17:50. [PMID: 27430330 PMCID: PMC4949774 DOI: 10.1186/s12868-016-0288-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/11/2016] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Polymorphisms in the gene for phosphatidylinositol binding clathrin assembly protein (PICALM), an endocytic-related protein, are associated with a small, increased risk of developing Alzheimer's disease (AD), strongly suggesting that changes in endocytosis are involved in the aetiology of the disease. We have investigated the involvement of PICALM in the processing of amyloid precursor protein (APP) to understand how PICALM could be linked to the development of AD. We used siRNA to deplete levels of PICALM, its isoforms and clathrin heavy chain in the human brain-derived H4 neuroglioma cell line that expresses endogenous levels of APP. We then used Western blotting, ELISA and immunohistochemistry to detect intra- and extracellular protein levels of endocytic-related proteins, APP and APP metabolites including β-amyloid (Aβ). Levels of functional endocytosis were quantified using ALEXA 488-conjugated transferrin and flow cytometry as a marker of clathrin-mediated endocytosis (CME). RESULTS Following depletion of all the isoforms of PICALM by siRNA in H4 cells, levels of intracellular APP, intracellular β-C-terminal fragment (β-CTF) and secreted sAPPβ (APP fragments produced by β-secretase cleavage) were significantly reduced but Aβ40 was not affected. Functional endocytosis was significantly reduced after both PICALM and clathrin depletion, highlighting the importance of PICALM in this process. However, depletion of clathrin did not affect APP but did reduce β-CTF levels. PICALM depletion altered the intracellular distribution of clathrin while clathrin reduction affected the subcellular pattern of PICALM labelling. Both PICALM and clathrin depletion reduced the expression of BACE1 mRNA and PICALM siRNA reduced protein levels. Individual depletion of PICALM isoforms 1 and 2 did not affect APP levels while clathrin depletion had a differential effect on the isoforms, increasing isoform 1 while decreasing isoform 2 expression. CONCLUSIONS The depletion of PICALM in brain-derived cells has significant effects on the processing of APP, probably by reducing CME. In particular, it affects the production of β-CTF which is increasingly considered to be an important mediator in AD independent of Aβ. Thus a decrease in PICALM expression in the brain could be beneficial to slow or prevent the development of AD.
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Affiliation(s)
- Rhian S. Thomas
- />School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3NB UK
| | - Alex Henson
- />School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3NB UK
| | - Amy Gerrish
- />MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
- />West Midlands Regional Genetics Laboratory, Birmingham Women’s NHS Foundation Trust, Mindelsohn Way, Edgbaston, Birmingham, B15 2TG UK
| | - Lesley Jones
- />MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Julie Williams
- />MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ UK
| | - Emma J. Kidd
- />School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3NB UK
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11
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Robinson MS. Forty Years of Clathrin-coated Vesicles. Traffic 2015; 16:1210-38. [PMID: 26403691 DOI: 10.1111/tra.12335] [Citation(s) in RCA: 234] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 12/11/2022]
Abstract
The purification of coated vesicles and the discovery of clathrin by Barbara Pearse in 1975 was a landmark in cell biology. Over the past 40 years, work from many labs has uncovered the molecular details of clathrin and its associated proteins, including how they assemble into a coated vesicle and how they select cargo. Unexpected connections have been found with signalling, development, neuronal transmission, infection, immunity and genetic disorders. But there are still a number of unanswered questions, including how clathrin-mediated trafficking is regulated and how the machinery evolved.
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Affiliation(s)
- Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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12
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Zhao Z, Sagare AP, Ma Q, Halliday MR, Kong P, Kisler K, Winkler EA, Ramanathan A, Kanekiyo T, Bu G, Owens NC, Rege SV, Si G, Ahuja A, Zhu D, Miller CA, Schneider JA, Maeda M, Maeda T, Sugawara T, Ichida JK, Zlokovic BV. Central role for PICALM in amyloid-β blood-brain barrier transcytosis and clearance. Nat Neurosci 2015; 18:978-87. [PMID: 26005850 PMCID: PMC4482781 DOI: 10.1038/nn.4025] [Citation(s) in RCA: 310] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/21/2015] [Indexed: 12/11/2022]
Abstract
PICALM is a highly validated genetic risk factor for Alzheimer's disease (AD). We found that reduced expression of PICALM in AD and murine brain endothelium correlated with amyloid-β (Aβ) pathology and cognitive impairment. Moreover, Picalm deficiency diminished Aβ clearance across the murine blood-brain barrier (BBB) and accelerated Aβ pathology in a manner that was reversible by endothelial PICALM re-expression. Using human brain endothelial monolayers, we found that PICALM regulated PICALM/clathrin-dependent internalization of Aβ bound to the low density lipoprotein receptor related protein-1, a key Aβ clearance receptor, and guided Aβ trafficking to Rab5 and Rab11, leading to Aβ endothelial transcytosis and clearance. PICALM levels and Aβ clearance were reduced in AD-derived endothelial monolayers, which was reversible by adenoviral-mediated PICALM transfer. Inducible pluripotent stem cell-derived human endothelial cells carrying the rs3851179 protective allele exhibited higher PICALM levels and enhanced Aβ clearance. Thus, PICALM regulates Aβ BBB transcytosis and clearance, which has implications for Aβ brain homeostasis and clearance therapy.
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Affiliation(s)
- Zhen Zhao
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Abhay P. Sagare
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Qingyi Ma
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Matthew R. Halliday
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Pan Kong
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Kassandra Kisler
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ethan A. Winkler
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anita Ramanathan
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Nelly Chuqui Owens
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Sanket V. Rege
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Gabriel Si
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ashim Ahuja
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Donghui Zhu
- Department of Chemical, Biological and Bio–Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA
| | - Carol A. Miller
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Julie A. Schneider
- Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Manami Maeda
- Division of Hematopoietic Stem Cell and Leukemia Research, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
- Division of Hematology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Takahiro Maeda
- Division of Hematopoietic Stem Cell and Leukemia Research, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
- Division of Hematology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Tohru Sugawara
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, 1425 San Pablo Street, BCC 307, Los Angeles, CA 90089, USA
| | - Justin K. Ichida
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, 1425 San Pablo Street, BCC 307, Los Angeles, CA 90089, USA
| | - Berislav V. Zlokovic
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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13
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Mercer JL, Argus JP, Crabtree DM, Keenan MM, Wilks MQ, Chi JTA, Bensinger SJ, Lavau CP, Wechsler DS. Modulation of PICALM Levels Perturbs Cellular Cholesterol Homeostasis. PLoS One 2015; 10:e0129776. [PMID: 26075887 PMCID: PMC4467867 DOI: 10.1371/journal.pone.0129776] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 05/12/2015] [Indexed: 12/21/2022] Open
Abstract
PICALM (Phosphatidyl Inositol Clathrin Assembly Lymphoid Myeloid protein) is a ubiquitously expressed protein that plays a role in clathrin-mediated endocytosis. PICALM also affects the internalization and trafficking of SNAREs and modulates macroautophagy. Chromosomal translocations that result in the fusion of PICALM to heterologous proteins cause leukemias, and genome-wide association studies have linked PICALM Single Nucleotide Polymorphisms (SNPs) to Alzheimer's disease. To obtain insight into the biological role of PICALM, we performed gene expression studies of PICALM-deficient and PICALM-expressing cells. Pathway analysis demonstrated that PICALM expression influences the expression of genes that encode proteins involved in cholesterol biosynthesis and lipoprotein uptake. Gas Chromatography-Mass Spectrometry (GC-MS) studies indicated that loss of PICALM increases cellular cholesterol pool size. Isotopic labeling studies revealed that loss of PICALM alters increased net scavenging of cholesterol. Flow cytometry analyses confirmed that internalization of the LDL receptor is enhanced in PICALM-deficient cells as a result of higher levels of LDLR expression. These findings suggest that PICALM is required for cellular cholesterol homeostasis and point to a novel mechanism by which PICALM alterations may contribute to disease.
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Affiliation(s)
- Jacob L. Mercer
- Department of Pharmacology & Cancer Biology, Duke University, Durham, North Carolina, United States of America
| | - Joseph P. Argus
- Department of Microbiology, Immunology and Molecular Genetics, Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Donna M. Crabtree
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Duke University, Durham, North Carolina, United States of America
| | - Melissa M. Keenan
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - Moses Q. Wilks
- Department of Radiology, Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Jen-Tsan Ashley Chi
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - Steven J. Bensinger
- Department of Microbiology, Immunology and Molecular Genetics, Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Catherine P. Lavau
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Duke University, Durham, North Carolina, United States of America
| | - Daniel S. Wechsler
- Department of Pharmacology & Cancer Biology, Duke University, Durham, North Carolina, United States of America
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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14
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Abstract
Endocytosis, the process whereby the plasma membrane invaginates to form vesicles, is essential for bringing many substances into the cell and for membrane turnover. The mechanism driving clathrin-mediated endocytosis (CME) involves > 50 different protein components assembling at a single location on the plasma membrane in a temporally ordered and hierarchal pathway. These proteins perform precisely choreographed steps that promote receptor recognition and clustering, membrane remodeling, and force-generating actin-filament assembly and turnover to drive membrane invagination and vesicle scission. Many critical aspects of the CME mechanism are conserved from yeast to mammals and were first elucidated in yeast, demonstrating that it is a powerful system for studying endocytosis. In this review, we describe our current mechanistic understanding of each step in the process of yeast CME, and the essential roles played by actin polymerization at these sites, while providing a historical perspective of how the landscape has changed since the preceding version of the YeastBook was published 17 years ago (1997). Finally, we discuss the key unresolved issues and where future studies might be headed.
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Affiliation(s)
- Bruce L Goode
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Julian A Eskin
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Beverly Wendland
- The Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218
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15
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Brodsky FM, Sosa RT, Ybe JA, O'Halloran TJ. Unconventional functions for clathrin, ESCRTs, and other endocytic regulators in the cytoskeleton, cell cycle, nucleus, and beyond: links to human disease. Cold Spring Harb Perspect Biol 2014; 6:a017004. [PMID: 25183831 DOI: 10.1101/cshperspect.a017004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The roles of clathrin, its regulators, and the ESCRT (endosomal sorting complex required for transport) proteins are well defined in endocytosis. These proteins can also participate in intracellular pathways that are independent of endocytosis and even independent of the membrane trafficking function of these proteins. These nonendocytic functions involve unconventional biochemical interactions for some endocytic regulators, but can also exploit known interactions for nonendocytic functions. The molecular basis for the involvement of endocytic regulators in unconventional functions that influence the cytoskeleton, cell cycle, signaling, and gene regulation are described here. Through these additional functions, endocytic regulators participate in pathways that affect infection, glucose metabolism, development, and cellular transformation, expanding their significance in human health and disease.
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Affiliation(s)
- Frances M Brodsky
- Department of Bioengineering and Therapeutic Sciences, Departments of Pharmaceutical Chemistry and Microbiology and Immunology, The G.W. Hooper Foundation, University of California, San Francisco, San Francisco, California 94143-0552
| | - R Thomas Sosa
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712-1095
| | - Joel A Ybe
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405
| | - Theresa J O'Halloran
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712-1095
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16
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Moshkanbaryans L, Chan LS, Graham ME. The Biochemical Properties and Functions of CALM and AP180 in Clathrin Mediated Endocytosis. MEMBRANES 2014; 4:388-413. [PMID: 25090048 PMCID: PMC4194041 DOI: 10.3390/membranes4030388] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/03/2014] [Accepted: 07/22/2014] [Indexed: 01/26/2023]
Abstract
Clathrin-mediated endocytosis (CME) is a fundamental process for the regulated internalization of transmembrane cargo and ligands via the formation of vesicles using a clathrin coat. A vesicle coat is initially created at the plasma membrane by clathrin assembly into a lattice, while a specific cargo sorting process selects and concentrates proteins for inclusion in the new vesicle. Vesicles formed via CME traffic to different parts of the cell and fuse with target membranes to deliver cargo. Both clathrin assembly and cargo sorting functions are features of the two gene family consisting of assembly protein 180 kDa (AP180) and clathrin assembly lymphoid myeloid leukemia protein (CALM). In this review, we compare the primary structure and domain organization of CALM and AP180 and relate these properties to known functions and roles in CME and disease.
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Affiliation(s)
- Lia Moshkanbaryans
- Children's Medical Research Institute, The University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2145, Australia.
| | - Ling-Shan Chan
- Children's Medical Research Institute, The University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2145, Australia.
| | - Mark E Graham
- Children's Medical Research Institute, The University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2145, Australia.
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17
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Suzuki M, Yamagata K, Shino M, Aikawa Y, Akashi K, Watanabe T, Kitabayashi I. Nuclear export signal within CALM is necessary for CALM-AF10-induced leukemia. Cancer Sci 2014; 105:315-23. [PMID: 24397609 PMCID: PMC4317939 DOI: 10.1111/cas.12347] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/05/2013] [Accepted: 12/30/2013] [Indexed: 01/24/2023] Open
Abstract
The CALM–AF10 fusion gene, which results from a t(10;11) translocation, is found in a variety of hematopoietic malignancies. Certain HOXA cluster genes and MEIS1 genes are upregulated in patients and mouse models that express CALM-AF10. Wild-type clathrin assembly lymphoid myeloid leukemia protein (CALM) primarily localizes in a diffuse pattern within the cytoplasm, whereas AF10 localizes in the nucleus; however, it is not clear where CALM-AF10 acts to induce leukemia. To investigate the influence of localization on leukemogenesis involving CALM-AF10, we determined the nuclear export signal (NES) within CALM that is necessary and sufficient for cytoplasmic localization of CALM-AF10. Mutations in the NES eliminated the capacity of CALM-AF10 to immortalize murine bone-marrow cells in vitro and to promote development of acute myeloid leukemia in mouse models. Furthermore, a fusion of AF10 with the minimal NES can immortalize bone-marrow cells and induce leukemia in mice. These results suggest that during leukemogenesis, CALM-AF10 plays its critical roles in the cytoplasm.
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Affiliation(s)
- Mai Suzuki
- Division of Hematological Malignancy, National Cancer Center Research Institute, Tokyo, Japan
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18
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Abstract
Membrane trafficking and mitosis are two essential processes in eukaryotic cells. Surprisingly, many proteins best known for their role in membrane trafficking have additional 'moonlighting' functions in mitosis. Despite having proteins in common, there is insufficient evidence for a specific connection between these two processes. Instead, these phenomena demonstrate the adaptability of the membrane trafficking machinery that allows its repurposing for different cellular functions.
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Affiliation(s)
- Stephen J Royle
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Road, Coventry, CV4 7AL, UK.
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19
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Abstract
The t(10;11) chromosomal translocation gives rise to the CALM-AF10 fusion gene and is found in patients with aggressive and difficult-to-treat hematopoietic malignancies. CALM-AF10-driven leukemias are characterized by HOXA gene up-regulation and a global reduction in H3K79 methylation. DOT1L, the H3K79 methyltransferase, interacts with the octapeptide/leucine zipper domain of AF10, and this region has been shown to be necessary and sufficient for CALM-AF10-mediated transformation. However, the precise role of CALM in leukemogenesis remains unclear. Here, we show that CALM contains a nuclear export signal (NES) that mediates cytoplasmic localization of CALM-AF10 and is necessary for CALM-AF10-dependent transformation. Fusions of the CALM NES (NES(CALM)-AF10) or NES motifs from heterologous proteins (ABL1, Rev, PKIA, APC) in-frame with AF10 are sufficient to immortalize murine hematopoietic progenitors in vitro. The CALM NES is essential for CALM-AF10-dependent Hoxa gene up-regulation and aberrant H3K79 methylation, possibly by mislocalization of DOT1L. Finally, we observed that CALM-AF10 leukemia cells are selectively sensitive to inhibition of nuclear export by Leptomycin B. These findings uncover a novel mechanism of leukemogenesis mediated by the nuclear export pathway and support further investigation of the utility of nuclear export inhibitors as therapeutic agents for patients with CALM-AF10 leukemias.
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20
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Tsushima H, Malabarba MG, Confalonieri S, Senic-Matuglia F, Verhoef LGGC, Bartocci C, D'Ario G, Cocito A, Di Fiore PP, Salcini AE. A snapshot of the physical and functional wiring of the Eps15 homology domain network in the nematode. PLoS One 2013; 8:e56383. [PMID: 23424658 PMCID: PMC3570524 DOI: 10.1371/journal.pone.0056383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 01/13/2013] [Indexed: 12/12/2022] Open
Abstract
Protein interaction modules coordinate the connections within and the activity of intracellular signaling networks. The Eps15 Homology (EH) module, a protein-protein interaction domain that is a key feature of the EH-network, was originally identified in a few proteins involved in endocytosis and vesicle trafficking, and has subsequently also been implicated in actin reorganization, nuclear shuttling, and DNA repair. Here we report an extensive characterization of the physical connections and of the functional wirings of the EH-network in the nematode. Our data show that one of the major physiological roles of the EH-network is in neurotransmission. In addition, we found that the proteins of the network intersect, and possibly coordinate, a number of “territories” of cellular activity including endocytosis/recycling/vesicle transport, actin dynamics, general metabolism and signal transduction, ubiquitination/degradation of proteins, DNA replication/repair, and miRNA biogenesis and processing.
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Affiliation(s)
- Hanako Tsushima
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Maria Grazia Malabarba
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Dipartimento di Medicina, Chirurgia ed Odontoiatria, Università degli Studi di Milano, Milan, Italy
| | | | | | | | - Cristina Bartocci
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Giovanni D'Ario
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Andrea Cocito
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Pier Paolo Di Fiore
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Dipartimento di Medicina, Chirurgia ed Odontoiatria, Università degli Studi di Milano, Milan, Italy
- Istituto Europeo di Oncologia, Milan, Italy
- * E-mail: (PPDF); (AES)
| | - Anna Elisabetta Salcini
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
- * E-mail: (PPDF); (AES)
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21
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The PICALM protein plays a key role in iron homeostasis and cell proliferation. PLoS One 2012; 7:e44252. [PMID: 22952941 PMCID: PMC3431333 DOI: 10.1371/journal.pone.0044252] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 07/31/2012] [Indexed: 01/16/2023] Open
Abstract
The ubiquitously expressed phosphatidylinositol binding clathrin assembly (PICALM) protein associates with the plasma membrane, binds clathrin, and plays a role in clathrin-mediated endocytosis. Alterations of the human PICALM gene are present in aggressive hematopoietic malignancies, and genome-wide association studies have recently linked the PICALM locus to late-onset Alzheimer's disease. Inactivating and hypomorphic Picalm mutations in mice cause different degrees of severity of anemia, abnormal iron metabolism, growth retardation and shortened lifespan. To understand PICALM’s function, we studied the consequences of PICALM overexpression and characterized PICALM-deficient cells derived from mutant fit1 mice. Our results identify a role for PICALM in transferrin receptor (TfR) internalization and demonstrate that the C-terminal PICALM residues are critical for its association with clathrin and for the inhibitory effect of PICALM overexpression on TfR internalization. Murine embryonic fibroblasts (MEFs) that are deficient in PICALM display several characteristics of iron deficiency (increased surface TfR expression, decreased intracellular iron levels, and reduced cellular proliferation), all of which are rescued by retroviral PICALM expression. The proliferation defect of cells that lack PICALM results, at least in part, from insufficient iron uptake, since it can be corrected by iron supplementation. Moreover, PICALM-deficient cells are particularly sensitive to iron chelation. Taken together, these data reveal that PICALM plays a critical role in iron homeostasis, and offer new perspectives into the pathogenesis of PICALM-associated diseases.
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22
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Abstract
EHD {EH [Eps15 (epidermal growth factor receptor substrate 15) homology]-domain-containing} proteins participate in several endocytic events, such as the internalization and the recycling processes. There are four EHD proteins in mammalian cells, EHD1–EHD4, each with diverse roles in the recycling pathway of endocytosis. EHD2 is a plasma-membrane-associated member of the EHD family that regulates internalization. Since several endocytic proteins have been shown to undergo nucleocytoplasmic shuttling and have been assigned roles in regulation of gene expression, we tested the possibility that EHD proteins also shuttle to the nucleus. Our results showed that, among the three EHD proteins (EHD1–EHD3) that were tested, only EHD2 accumulates in the nucleus under nuclear export inhibition treatment. Moreover, the presence of a NLS (nuclear localization signal) was essential for its entry into the nucleus. Nuclear exit of EHD2 depended partially on its NES (nuclear export signal). Elimination of a potential SUMOylation site in EHD2 resulted in a major accumulation of the protein in the nucleus, indicating the involvement of SUMOylation in the nuclear exit of EHD2. We confirmed the SUMOylation of EHD2 by employing co-immunoprecipitation and the yeast two-hybrid system. Using GAL4-based transactivation assay as well as a KLF7 (Krüppel-like factor 7)-dependent transcription assay of the p21WAF1/Cip1 [CDKN1A (cyclin-dependent kinase inhibitor 1A)] gene, we showed that EHD2 represses transcription. qRT-PCR (quantitative real-time PCR) of RNA from cells overexpressing EHD2 or of RNA from cells knocked down for EHD2 confirmed that EHD2 represses transcription of the p21WAF1/Cip1 gene.
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23
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Buroker NE, Huang JY, Barboza J, Ledee DR, Eastman RJ, Reinecke H, Ning XH, Bassuk JA, Portman MA. The adaptor-related protein complex 2, alpha 2 subunit (AP2α2) gene is a peroxisome proliferator-activated receptor cardiac target gene. Protein J 2012; 31:75-83. [PMID: 22160327 DOI: 10.1007/s10930-011-9379-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A peroxisome proliferator-actived receptor (PPAR) response element (RE) in the promoter region of the adaptor-related protein complex 2, alpha 2 subunit (AP2α2) of mouse heart has been identified. The steroid hormone nuclear PPARs and the retinoid X receptors (RXRs) are important transcriptional factors that regulate gene expression, cell differentiation and lipid metabolism. They form homo- (RXR) and hetero- (PPAR-RXR) dimers that bind DNA at various REs. The AP2α2 gene is part of complex and process that transports lipids and proteins from the plasma membrane to the endosomal system. A PPAR activator (Wy14643) and DMSO (vehicle) was introduced into control and δ337T thyroid hormone receptor (TRβ1) transgenic mice. Heart tissue was extracted and AP2α2 gene expression was compared using Affymetrix expression arrays and qRT PCR among four groups [control, control with Wy14643, δ337T TRβ1 and δ337T TRβ1 with Wy14643]. The gene expression of AP2α2 in the Wy14643 control and transgenic mouse groups was significantly up regulated over the vehicle mouse groups in both the array (p < 0.01) and qRT PCR (p < 0.01) studies. Duplex oligo DNAs containing the PPAR/RXR motif (AGGTCA/TCCAGT) from the AP2α2 promoter were used in EMSA to verify binding of the PPAR and RXR receptors to their REs. pGL4.0 [Luc] constructs of the AP2α2 promoter with and without the PPAR/RXR motifs were co-transfected with mouse PPARα, β or γ1 into HepG2 cells and used in lucerifase assays to verify gene activation. In conclusion our study revealed that PPARα regulates the mouse cardiac AP2α2 gene in both the control and transgenic mouse.
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Affiliation(s)
- Norman E Buroker
- Department of Cardiology, Seattle Children's Research Institute, Seattle, WA 98101, USA.
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24
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Sen A, Madhivanan K, Mukherjee D, Aguilar RC. The epsin protein family: coordinators of endocytosis and signaling. Biomol Concepts 2012; 3:117-126. [PMID: 22942912 DOI: 10.1515/bmc-2011-0060] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The epsins are a conserved family of endocytic adaptors essential for cell viability in yeast and for embryo development in higher eukaryotes. Epsins function as adaptors by recognizing ubiquitinated cargo and as endocytic accessory proteins by contributing to endocytic network stability/regulation and membrane bending. Importantly, epsins play a critical role in signaling by contributing to epidermal growth factor receptor downregulation and the activation of notch and RhoGTPase pathways. In this review, we present an overview of the epsins and emphasize their functional importance as coordinators of endocytosis and signaling.
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Affiliation(s)
- Arpita Sen
- Department of Biological Sciences and Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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25
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Sigismund S, Confalonieri S, Ciliberto A, Polo S, Scita G, Di Fiore PP. Endocytosis and signaling: cell logistics shape the eukaryotic cell plan. Physiol Rev 2012; 92:273-366. [PMID: 22298658 DOI: 10.1152/physrev.00005.2011] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of endocytosis has evolved remarkably in little more than a decade. This is the result not only of advances in our knowledge of its molecular and biological workings, but also of a true paradigm shift in our understanding of what really constitutes endocytosis and of its role in homeostasis. Although endocytosis was initially discovered and studied as a relatively simple process to transport molecules across the plasma membrane, it was subsequently found to be inextricably linked with almost all aspects of cellular signaling. This led to the notion that endocytosis is actually the master organizer of cellular signaling, providing the cell with understandable messages that have been resolved in space and time. In essence, endocytosis provides the communications and supply routes (the logistics) of the cell. Although this may seem revolutionary, it is still likely to be only a small part of the entire story. A wealth of new evidence is uncovering the surprisingly pervasive nature of endocytosis in essentially all aspects of cellular regulation. In addition, many newly discovered functions of endocytic proteins are not immediately interpretable within the classical view of endocytosis. A possible framework, to rationalize all this new knowledge, requires us to "upgrade" our vision of endocytosis. By combining the analysis of biochemical, biological, and evolutionary evidence, we propose herein that endocytosis constitutes one of the major enabling conditions that in the history of life permitted the development of a higher level of organization, leading to the actuation of the eukaryotic cell plan.
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Affiliation(s)
- Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
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26
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Abstract
It is becoming clear that intracellular signaling events are intimately linked with the membrane transport processes. In addition to the long known role of endocytosis in downregulating plasma membrane receptors, more recent data uncover several sophisticated modes by which endocytosis affects the type and duration of signals. Particularly striking are various roles of endocytic compartments as membrane platforms for compartmentalized assembly or sequestration of specific signaling complexes. Here we review some recent examples illustrating how endosomes may mediate ligand-stimulated apoptotic signaling and how multivesicular bodies affect Wnt signaling by regulated sequestration of signaling molecules or their secretion in exosomes. We also discuss evidence documenting the involvement of endocytic proteins in the regulation of p53 activity and stability, which suggests a possible cross-talk between endocytic processes and transcriptional responses.
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Affiliation(s)
- Anna Hupalowska
- International Institute of Molecular and Cell Biology, Laboratory of Cell Biology, 4 Ks. Trojdena Street, Warsaw, Poland
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27
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Anandharaj A, Yu JR, Park WY. Phosphorylation of threonine 190 is essential for nuclear localization and endocytosis of the FTS (Fused Toes Homolog) protein. Int J Biol Macromol 2011; 49:721-8. [PMID: 21777610 DOI: 10.1016/j.ijbiomac.2011.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/04/2011] [Accepted: 07/05/2011] [Indexed: 10/18/2022]
Abstract
Fused Toes Homolog (FTS) is a member of a group of proteins termed as E2 variants and this group of proteins lacks an active cysteine residue that is required for ubiquitin transfer. We have identified the expression of this protein in early neoplastic stages of cervical cancer and its translocation into nucleus from cytoplasm upon irradiation. Here we have reported that a threonine residue at position 190 is essential for its nucleocytoplasmic shuttling and function. Upon LMB treatment we found that FTS was located in the nucleus and it suggests that direct role of nuclear export signal (NES) is required for the binding to CRM1 and facilitates nuclear export. The threonine residue was phosphorylated and promoted the phosphorylation of EGFR, p38 and JNK facilitating vesicular trafficking of early to late endosomes. Mutational change of the threonine into alanine resulted in the cytoplasmic localization of FTS and failed to phosphorylate EGFR and its downstream effector proteins. In addition the mutation also reduced the number of early endosomes formed and also resulted in the clustering of late endosomes around the perinuclear region. These data suggest that threonine residue of FTS at position 190 is not only essential for its function but also for the formation, maturation and trafficking of early endosomes to late endosome/lysosome, as well as we speculate that FTS may function at a connection point in the vesicle tethering.
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Affiliation(s)
- Arunkumar Anandharaj
- Department of Radiation Oncology, Chungbuk National University College of Medicine, Cheongju, Republic of Korea
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28
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Abstract
In recent years, cell biologists have uncovered a number of new functions for proteins that were previously thought to operate solely in membrane trafficking. These alternative roles, termed moonlighting functions, can occur at distinct intracellular sites or at different stages of the cell cycle. Here, I evaluate the evidence for mitotic moonlighting functions of proteins that have membrane trafficking roles during interphase. The aim is to identify key issues facing the field and to outline important questions for future work.
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Affiliation(s)
- Stephen J Royle
- Physiological Laboratory, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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Stoddart A, Tennant TR, Fernald AA, Anastasi J, Brodsky FM, Le Beau MM. The clathrin-binding domain of CALM-AF10 alters the phenotype of myeloid neoplasms in mice. Oncogene 2011; 31:494-506. [PMID: 21706055 PMCID: PMC3204175 DOI: 10.1038/onc.2011.251] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The PICALM (CALM) gene, whose product is involved in clathrin-mediated endocytosis, has been identified in two recurring chromosomal translocations, involving either MLL or MLLT10 (AF10). We developed a mouse model of CALM-AF10+ leukemia to examine the hypothesis that disruption of endocytosis contributes to leukemogenesis. Exclusion of the C-terminal portion of CALM from the fusion protein, which is required for optimal binding to clathrin, resulted in the development of a myeloproliferative disease, while inclusion of this domain led to the development of acute myeloid leukemia and changes in gene expression of several cancer-related genes, notably Pim1 and Crebbp. Nonetheless, the development of leukemia could not be attributed directly to interference with endocytosis or consequential changes in proliferation and signaling. In leukemia cells, full-length CALM-AF10 localized to the nucleus with no consistent effect on growth factor endocyctosis, and suppressed H3K79 methylation regardless of the presence of clathrin. Using FRET analysis, we show that CALM-AF10 has a propensity to homo-oligomerize, raising the possibility that the function of endocytic proteins involved in chimeric fusions may be to provide dimerization properties, a recognized mechanism for unleashing oncogenic properties of chimeric transcription factors, rather than disrupting the internalization of growth factor receptors.
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Affiliation(s)
- A Stoddart
- Department of Medicine, Section of Hematology/Oncology, University of Chicago, Chicago, IL 60637, USA.
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30
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Wallenstein EJ, Barminko J, Schloss RS, Yarmush ML. Serum starvation improves transient transfection efficiency in differentiating embryonic stem cells. Biotechnol Prog 2011; 26:1714-23. [PMID: 20574993 DOI: 10.1002/btpr.472] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Control of genetic expression is a critical issue in the field of stem cell biology, where determining a cell fate or reprogramming adult somatic cells into pluripotent cells has become a common experimental practice. In turn, for these cells to have therapeutic clinical potential, techniques for controlling gene expression are needed that minimizes or eliminates the risk of oncogenesis and mutagenesis. Possible routes for achieving this outcome could come in the form of a transient nonviral gene delivery system. In this study, we improved the efficiency of transient gene delivery to differentiating murine embryonic stem (ES) cells via serum starvation for 3 days before transfection. The transient expression of a constitutively-controlled plasmid increased from ∼50% (replated control) to ∼83% when transfected after 3 days of serum starvation but decreased to ∼28% when transfected after 3 days in normal high serum-containing media. When probed with a liver-specific reporter, Cyp7A1, expression increased from ∼1.4% (replated control) to ∼3.7% when transfected after 3 days of serum starvation but decreased to ∼0.7% when transfected after 3 days in high serum-containing media. Cy3-tagged oligonucleotides were used to rapidly quantify DNA uptake and predict ultimate transfection efficiency. This study suggests that modifications in media serum levels before transfection can have a profound effect on improving nonviral gene delivery.
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Affiliation(s)
- Eric J Wallenstein
- Dept. of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, USA
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31
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Carter C. Alzheimer's disease plaques and tangles: Cemeteries of a Pyrrhic victory of the immune defence network against herpes simplex infection at the expense of complement and inflammation-mediated neuronal destruction. Neurochem Int 2011; 58:301-20. [DOI: 10.1016/j.neuint.2010.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 11/30/2010] [Accepted: 12/01/2010] [Indexed: 12/29/2022]
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32
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Montanini B, Levati E, Bolchi A, Kohler A, Morin E, Tisserant E, Martin F, Ottonello S. Genome-wide search and functional identification of transcription factors in the mycorrhizal fungus Tuber melanosporum. THE NEW PHYTOLOGIST 2011; 189:736-750. [PMID: 21058951 DOI: 10.1111/j.1469-8137.2010.03525.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
• Developmental transitions associated with the life cycle of plant-symbiotic fungi, such as the ascomycete Tuber melanosporum, are likely to require an extensive reprogramming of gene expression brought about by transcription factors (TFs). To date, little is known about the transcriptome alterations that accompany developmental shifts associated with symbiosis or fruiting body formation. • Taking advantage of the black truffle genome sequence, we used a bioinformatic approach, coupled with functional analysis in yeast and transcriptome profiling, to identify and catalogue T. melanosporum TFs, the so-called 'regulome'. • The T. melanosporum regulome contains 102 homologs of previously characterized TFs, 57 homologs of hypothetical TFs, and 42 putative TFs apparently unique to Tuber. The yeast screen allowed the functional discovery of four TFs and the validation of about one-fifth of the in silico predicted TFs. Truffle proteins apparently unrelated to transcription were also identified as potential transcriptional regulators, together with a number of plant TFs. • Twenty-nine TFs, some of which associated with particular developmental stages, were found to be up-regulated in ECMs or fruiting bodies. About one-quarter of these up-regulated TFs are expressed at surprisingly high levels, thus pointing to a striking functional specialization of the different stages of the Tuber life cycle.
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Affiliation(s)
- Barbara Montanini
- Department of Biochemistry and Molecular Biology, University of Parma, 43100 Parma, Italy
| | - Elisabetta Levati
- Department of Biochemistry and Molecular Biology, University of Parma, 43100 Parma, Italy
| | - Angelo Bolchi
- Department of Biochemistry and Molecular Biology, University of Parma, 43100 Parma, Italy
| | - Annegret Kohler
- Ecogenomics of Interactions Lab, UMR 'Interactions Arbres/Micro-Organismes', INRA-Nancy, 54280 Champenoux, France
| | - Emmanuelle Morin
- Ecogenomics of Interactions Lab, UMR 'Interactions Arbres/Micro-Organismes', INRA-Nancy, 54280 Champenoux, France
| | - Emilie Tisserant
- Ecogenomics of Interactions Lab, UMR 'Interactions Arbres/Micro-Organismes', INRA-Nancy, 54280 Champenoux, France
| | - Francis Martin
- Ecogenomics of Interactions Lab, UMR 'Interactions Arbres/Micro-Organismes', INRA-Nancy, 54280 Champenoux, France
| | - Simone Ottonello
- Department of Biochemistry and Molecular Biology, University of Parma, 43100 Parma, Italy
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33
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Pece S, Confalonieri S, R Romano P, Di Fiore PP. NUMB-ing down cancer by more than just a NOTCH. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1815:26-43. [PMID: 20940030 DOI: 10.1016/j.bbcan.2010.10.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/30/2010] [Accepted: 10/02/2010] [Indexed: 02/07/2023]
Abstract
The protein Numb does not live up to its name. This passive-sounding protein is anything but spent. Originally identified as a cell-fate determinant in Drosophila development, Numb received a good deal of attention as an inhibitor of the Notch receptor signaling pathway. It turns out, however, that Numb does a lot more than simply regulate Notch. It has been implicated in a variety of biochemical pathways connected with signaling (it regulates Notch-, Hedgehog- and TP53-activated pathways), endocytosis (it is involved in cargo internalization and recycling), determination of polarity (it interacts with the PAR complex, and regulates adherens and tight junctions), and ubiquitination (it exploits this mechanism to regulate protein function and stability). This complex biochemical network lies at the heart of Numb's involvement in diverse cellular phenotypes, including cell fate developmental decisions, maintenance of stem cell compartments, regulation of cell polarity and adhesion, and migration. Considering its multifaceted role in cellular homeostasis, it is not surprising that Numb has been implicated in cancer as a tumor suppressor. Our major goal here is to explain the cancer-related role of Numb based on our understanding of its role in cell physiology. We will attempt to do this by reviewing the present knowledge of Numb at the biochemical and functional level, and by integrating its apparently heterogeneous functions into a unifying scenario, based on our recently proposed concept of the "endocytic matrix". Finally, we will discuss the role of Numb in the maintenance of the normal stem cell compartment, as a starting point to interpret the tumor suppressor function of Numb in the context of the cancer stem cell hypothesis.
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Affiliation(s)
- Salvatore Pece
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
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34
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APP, APOE, complement receptor 1, clusterin and PICALM and their involvement in the herpes simplex life cycle. Neurosci Lett 2010; 483:96-100. [PMID: 20674675 DOI: 10.1016/j.neulet.2010.07.066] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 06/29/2010] [Accepted: 07/23/2010] [Indexed: 12/19/2022]
Abstract
The major Alzheimer's disease susceptibility genes (APOE, clusterin, complement receptor 1 (CR1) and phosphatidylinositol binding clathrin assembly protein, PICALM) can be implicated directly (APOE, CR1) or indirectly (clusterin and PICALM) in the herpes simplex life cycle. The virus binds to proteoliposomes containing APOE or APOA1 and also to CR1, and both clusterin and PICALM are related to a mannose-6-phosphate receptor used by the virus for cellular entry and intracellular transport. PICALM also binds to a nuclear exportin used by the virus for nuclear egress. Clusterin and complement receptor 1 are both related to the complement pathways and play a general role in pathogen defence. In addition, the amyloid precursor protein APP is involved in herpes viral transport and gamma-secretase cleaves a number of receptors used by the virus for cellular entry. APOE, APOA1 and clusterin, or alpha 2-macroglobulin, insulysin and caspase 3, which also bind to the virus, are involved in beta-amyloid clearance or degradation, as are the viral binding complement components, C3 and CR1. There are multiple ways in which the products of key susceptibility genes might be able to modify the viral life cycle and in turn the virus interacts with key proteins involved in APP and beta-amyloid processing. These interactions support a role for the herpes simplex virus in Alzheimer's disease pathology and suggest that antiviral agents or vaccination might be considered as viable therapeutic strategies in Alzheimer's disease.
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35
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Zhang J, Li H, Herrup K. Cdk5 nuclear localization is p27-dependent in nerve cells: implications for cell cycle suppression and caspase-3 activation. J Biol Chem 2010; 285:14052-61. [PMID: 20189989 DOI: 10.1074/jbc.m109.068262] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Initiation of a cell cycle in an adult neuron leads to cell death, placing great importance on the mechanisms that normally suppress the neuronal cell cycle. We have previously shown that the cyclin-dependent kinase Cdk5 is an important part of this process, but only when it is present in the nucleus. We report here that Cdk5 nuclear localization relies on its binding to the cyclin-dependent kinase inhibitor p27. Cdk5 has no intrinsic nuclear localization signal; in the absence of p27, two weak nuclear export signals that bind CRM1 cause it to shuttle to the cytoplasm. When a neuron is subjected to stress, such as exposure to beta-amyloid, the Cdk5-p27 interaction is lost, reducing Cdk5 levels in the nucleus and depriving the neuron of a major cell cycle suppression mechanism. Caspase-3 is activated within hours, but death is not immediate; elevated levels of cytoplasmic Cdk5 appear to retard neuronal death by a mechanism that may involve Bcl2. These data suggest a model in which Cdk5 exerts a double protective function in neurons: chronically suppressing the cell cycle when located in the nucleus and transiently delaying cell death in the cytoplasm.
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Affiliation(s)
- Jie Zhang
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8082, USA
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36
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Lindsay AJ, McCaffrey MW. Myosin Vb localises to nucleoli and associates with the RNA polymerase I transcription complex. ACTA ACUST UNITED AC 2010; 66:1057-72. [PMID: 19610025 DOI: 10.1002/cm.20408] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It is becoming increasingly clear that the mammalian class V myosins are involved in a wide range of cellular processes such as receptor trafficking, mRNA transport, myelination in oligodendrocytes and cell division. Using paralog-specific antibodies, we observed significant nuclear localisation for both myosin Va and myosin Vb. Myosin Vb was present in nucleoli where it co-localises with RNA polymerase I, and newly synthesised ribosomal RNA (rRNA), indicating that it may play a role in transcription. Indeed, its nucleolar pattern was altered upon treatment with RNA polymerase I inhibitors. In contrast, myosin Va is largely excluded from nucleoli and is unaffected by these inhibitors. Myosin Vb was also found to physically associate with RNA polymerase I and actin in co-immunoprecipitation experiments. We propose that myosin Vb serves a role in rRNA transcription.
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Affiliation(s)
- Andrew J Lindsay
- Molecular Cell Biology Laboratory, Department of Biochemistry, Biosciences Institute, University College Cork, Cork, Ireland
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37
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Lobanov VA, Zheng C, Babiuk LA, van Drunen Littel-van den Hurk S. Intracellular trafficking of VP22 in bovine herpesvirus-1 infected cells. Virology 2009; 396:189-202. [PMID: 19922972 DOI: 10.1016/j.virol.2009.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 08/05/2009] [Accepted: 10/15/2009] [Indexed: 11/24/2022]
Abstract
The intracellular trafficking of different VP22-enhanced yellow fluorescent protein (EYFP) fusion proteins expressed by bovine herpesvirus-1 (BHV-1) recombinants was examined by live-cell imaging. Our results demonstrate that (i) the fusion of EYFP to the C terminus of VP22 does not alter the trafficking of the protein in infected cells, (ii) VP22 expressed during BHV-1 infection translocates to the nucleus through three different pathways, namely early mitosis-dependent nuclear translocation, late massive nuclear translocation that follows a prolonged cytoplasmic stage of the protein in non-mitotic cells, and accumulation of a small subset of VP22 in discrete dot-like nuclear domains during its early cytoplasmic stage, (iii) the addition of the SV40 large-T-antigen nuclear localization signal (NLS) to VP22-EYFP abrogates its early cytoplasmic stage, and (iv) the VP22 (131)PRPR(134) NLS is not required for the late massive nuclear translocation of the protein, but this motif is essential for the targeting of VP22 to discrete dot-like nuclear domains during the early cytoplasmic stage. These results show that the amount of VP22 in the nucleus is precisely regulated at different stages of BHV-1 infection and suggest that the early pathways of VP22 nuclear accumulation may be more relevant to the infection process as the late massive nuclear influx starts when most of the viral progeny has already emerged from the cell.
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Affiliation(s)
- Vladislav A Lobanov
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada
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38
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van Bergen En Henegouwen PM. Eps15: a multifunctional adaptor protein regulating intracellular trafficking. Cell Commun Signal 2009; 7:24. [PMID: 19814798 PMCID: PMC2767346 DOI: 10.1186/1478-811x-7-24] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 10/08/2009] [Indexed: 12/30/2022] Open
Abstract
Over expression of receptor tyrosine kinases is responsible for the development of a wide variety of malignancies. Termination of growth factor signaling is primarily determined by the down regulation of active growth factor/receptor complexes. In recent years, considerable insight has been gained in the endocytosis and degradation of growth factor receptors. A crucial player in this process is the EGFR Protein tyrosine kinase Substrate #15, or Eps15. This protein functions as a scaffolding adaptor protein and is involved both in secretion and endocytosis. Eps15 has been shown to bind to AP-1 and AP-2 complexes, to bind to inositol lipids and to several other proteins involved in the regulation of intracellular trafficking. In addition, Eps15 has been detected in the nucleus of mammalian cells. Activation of growth factor receptors induces tyrosine phosphorylation and mono-ubiquitination of Eps15. The role of these post translational modifications of Eps15 is still a mystery. It is proposed that Eps15 and its family members Eps15R and Eps15b are involved in the regulation of membrane morphology, which is required for intracellular vesicle formation and trafficking.
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39
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Borlido J, Zecchini V, Mills IG. Nuclear Trafficking and Functions of Endocytic Proteins Implicated in Oncogenesis. Traffic 2009; 10:1209-20. [DOI: 10.1111/j.1600-0854.2009.00922.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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40
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Pyrzynska B, Pilecka I, Miaczynska M. Endocytic proteins in the regulation of nuclear signaling, transcription and tumorigenesis. Mol Oncol 2009; 3:321-38. [PMID: 19577966 DOI: 10.1016/j.molonc.2009.06.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 06/01/2009] [Accepted: 06/02/2009] [Indexed: 01/14/2023] Open
Abstract
Accumulating evidence argues that many proteins governing membrane sorting during endocytosis participate also in nuclear signaling and transcriptional regulation, mostly by modulating the activity of various nuclear factors. Some adaptors and accessory proteins acting in clathrin-mediated internalization, as well as endosomal sorting proteins can undergo nuclear translocation and affect gene expression directly, while for others the effects may be more indirect. Although it is often unclear to what extent the endocytic and nuclear functions are interrelated, several of such proteins are implicated in the regulation of cell proliferation and tumorigenesis, arguing that their dual-function nature may be of physiological importance.
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Affiliation(s)
- Beata Pyrzynska
- International Institute of Molecular and Cell Biology, Laboratory of Cell Biology, 02-109 Warsaw, Poland
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41
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Liberali P, Kakkonen E, Turacchio G, Valente C, Spaar A, Perinetti G, Böckmann RA, Corda D, Colanzi A, Marjomaki V, Luini A. The closure of Pak1-dependent macropinosomes requires the phosphorylation of CtBP1/BARS. EMBO J 2008; 27:970-81. [PMID: 18354494 DOI: 10.1038/emboj.2008.59] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 02/29/2008] [Indexed: 12/22/2022] Open
Abstract
Membrane fission is an essential process in membrane trafficking and other cellular functions. While many fissioning and trafficking steps are mediated by the large GTPase dynamin, some fission events are dynamin independent and involve C-terminal-binding protein-1/brefeldinA-ADP ribosylated substrate (CtBP1/BARS). To gain an insight into the molecular mechanisms of CtBP1/BARS in fission, we have studied the role of this protein in macropinocytosis, a dynamin-independent endocytic pathway that can be synchronously activated by growth factors. Here, we show that upon activation of the epidermal growth factor receptor, CtBP1/BARS is (a) translocated to the macropinocytic cup and its surrounding membrane, (b) required for the fission of the macropinocytic cup and (c) phosphorylated on a specific serine that is a substrate for p21-activated kinase, with this phosphorylation being essential for the fission of the macropinocytic cup. Importantly, we also show that CtBP1/BARS is required for macropinocytic internalization and infection of echovirus 1. These results provide an insight into the molecular mechanisms of CtBP1/BARS activation in membrane fissioning, and extend the relevance of CtBP1/BARS-induced fission to human viral infection.
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Affiliation(s)
- Prisca Liberali
- Laboratory of Cell Regulation, Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro (Chieti), Italy
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42
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Commisso C, Boulianne GL. The neuralized homology repeat 1 domain of Drosophila neuralized mediates nuclear envelope association and delta-dependent inhibition of nuclear import. J Mol Biol 2008; 375:1125-40. [PMID: 18076903 DOI: 10.1016/j.jmb.2007.11.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 11/08/2007] [Accepted: 11/12/2007] [Indexed: 01/25/2023]
Abstract
Signaling by the Notch (N) pathway is critical for many developmental processes and requires complex trafficking of both the N receptor and its transmembrane ligands, Delta (Dl) and Serrate. neuralized encodes an E3 ubiquitin ligase required for N ligand internalization. Neuralized (Neur) is conserved from worms to humans and comprises two Neur homology repeat (NHR) domains, NHR1 and NHR2, and a carboxyl-terminal RING domain. We have previously shown that the RING domain is required for ubiquitin ligase activity and that NHR1 mediates binding to Dl, a ubiquitination target. In Drosophila, Neur associates with the plasma membrane and hepatocyte responsive serum phosphoprotein-positive endosomes. Here we demonstrate that Neur also exhibits nuclear envelope localization. We have determined that Neur subcellular localization is regulated by nuclear trafficking and that inhibition of chromosome region maintenance 1, a nuclear export receptor, interferes with Neur nuclear export, trapping Neur in the nucleus. Moreover, we demonstrate that nuclear envelope localization is mediated by the Neur NHR1 domain. Interestingly, Dl expression in Schneider cells is sufficient to inhibit Neur nuclear import and inhibition occurs in an NHR1-dependent manner, suggesting that Neur nuclear localization occurs in contexts where Dl expression is either low or absent. Consistent with this, we found that Neur exhibits nuclear trafficking and associates with the nuclear envelope in the secretory cells of the larval salivary gland and that overexpression of Dl can reduce Neur localization to the nucleus. Altogether, our data demonstrate that Neur localizes to the nuclear envelope and that this localization can be negatively regulated by Dl, suggesting a possible nuclear function for Neur in Drosophila.
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Affiliation(s)
- Cosimo Commisso
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada
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43
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Abstract
Tumor suppressor p53 protein is the transcription factor responsible for various genes including DNA repair, growth arrest, apoptosis and antiangiogenesis. Recently, we showed that clathrin heavy chain (CHC), which was originally identified as a cytosolic protein regulating endocytosis, is present in nuclei and functions as a coactivator for p53. Here, we determined the detailed p53-binding site of CHC and a CHC deletion mutant containing this region (CHC833-1406) behaved as a monomer in cells. Monomeric CHC833-1406 still had a higher ability to transactivate p53 than wild-type CHC although this CHC mutant no longer had endocytic function. Moreover, similar to wild-type CHC, monomeric CHC enhances p53-mediated transcription through the recruitment of histone acetyltransferase p300. Immunofluorescent microscopic analysis exhibited that CHC833-1406 is predominantly localized in nuclei, suggesting that there may be a certain regulatory domain for nuclear export in the C-terminus of CHC. Thus, the trimerization domain of CHC is not necessary for the transactivation of p53 target genes and these data provide further evidence that nuclear CHC plays a role distinct from clathrin-mediated endocytosis.
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44
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Pilecka I, Banach-Orlowska M, Miaczynska M. Nuclear functions of endocytic proteins. Eur J Cell Biol 2007; 86:533-47. [PMID: 17583371 DOI: 10.1016/j.ejcb.2007.04.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 04/19/2007] [Accepted: 04/19/2007] [Indexed: 01/14/2023] Open
Abstract
An increasing number of proteins appear to perform multiple, sometimes unrelated functions in the cell. Such moonlighting properties have been recently demonstrated for proteins involved in clathrin-mediated endocytosis. Some clathrin adaptors and endosomal proteins can undergo nucleocytoplasmic shuttling, which is often based on intrinsic sequence motifs and requires active transport mechanisms. Endocytic proteins can associate with nuclear molecules, changing their localization and/or activity and may modulate the levels and specificity of gene transcription. It is not clear how the nuclear and cytoplasmic pools of endocytic proteins are interconnected, or whether these molecules act as nuclear second messengers upon extracellular stimuli, but alike in endocytosis, they seem to form multi-component scaffolding platforms in the nucleus. Added to their endocytic functions, the nuclear roles of Eps15, Epsin1, CALM, HIP1, Dab1/2, beta-arrestins, APPL1/2 and the components of ESCRTs clearly increase the complexity of signaling networks affecting cellular growth, proliferation and homeostasis.
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Affiliation(s)
- Iwona Pilecka
- International Institute of Molecular and Cell Biology, Laboratory of Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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45
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Mills IG. The interplay between clathrin-coated vesicles and cell signalling. Semin Cell Dev Biol 2007; 18:459-70. [PMID: 17692542 DOI: 10.1016/j.semcdb.2007.07.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2007] [Revised: 06/28/2007] [Accepted: 07/02/2007] [Indexed: 01/26/2023]
Abstract
Internalization of cargo proteins and lipids at the cell surface occurs in both a constitutive and signal-regulated manner through clathrin-mediated and other endocytic pathways. Clathrin-coated vesicle formation is a principal uptake route in response to signalling events. Protein-lipid and protein-protein interactions control both the targeting of signalling molecules and their binding partners to membrane compartments and the assembly of clathrin coats. An emerging aspect of membrane trafficking research is now addressing how signalling cascades and vesicle coat assembly and subsequently disassembly are integrated.
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Affiliation(s)
- Ian G Mills
- Cancer Research UK, Cambridge Research Institute, Robinson Way, Cambridge CB2 ORE, UK.
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Gardiner FC, Costa R, Ayscough KR. Nucleocytoplasmic trafficking is required for functioning of the adaptor protein Sla1p in endocytosis. Traffic 2007; 8:347-58. [PMID: 17286805 PMCID: PMC1989034 DOI: 10.1111/j.1600-0854.2007.00534.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dual localization of proteins at the plasma membrane and within the nucleus has been reported in mammalian cells. Among these proteins are those involved in cell adhesion structures and in clathrin-mediated endocytosis. In the case of endocytic proteins, trafficking to the nucleus is not known to play a role in their endocytic function. Here, we show localization of the yeast endocytic adaptor protein Sla1p to the nucleus as well as to the cell cortex and we demonstrate the importance of specific regions of Sla1p for this nuclear localization. A role for specific karyopherins (importins and exportins) in Sla1p nuclear localization is revealed. Furthermore, endocytosis of Sla1p-dependent cargo is defective in three strains with karyopherin mutations. Finally, we investigate possible functions for nuclear trafficking of endocytic proteins. Our data reveal for the first time that nuclear transport of endocytic proteins is important for functional endocytosis in Saccharomyces cerevisiae. We determine the mechanism, involving an alpha/beta importin pair, that facilitates uptake of Sla1p and demonstrate that nuclear transport is required for the functioning of Sla1p during endocytosis.
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Affiliation(s)
- Fiona C. Gardiner
- Department of Molecular Biology and Biotechnology, University of Sheffield Firth Court, Western Bank Sheffield, S10 2TN Tel: +44 114 222 2309 Fax: +44 114 222 2800
| | - Rosaria Costa
- Department of Molecular Biology and Biotechnology, University of Sheffield Firth Court, Western Bank Sheffield, S10 2TN Tel: +44 114 222 2309 Fax: +44 114 222 2800
| | - Kathryn R. Ayscough
- Department of Molecular Biology and Biotechnology, University of Sheffield Firth Court, Western Bank Sheffield, S10 2TN Tel: +44 114 222 2309 Fax: +44 114 222 2800
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47
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Eun SH, Lea K, Overstreet E, Stevens S, Lee JH, Fischer JA. Identification of genes that interact with Drosophila liquid facets. Genetics 2006; 175:1163-74. [PMID: 17179082 PMCID: PMC1840095 DOI: 10.1534/genetics.106.067959] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have performed mutagenesis screens of the Drosophila X chromosome and the autosomes for dominant enhancers of the rough eye resulting from overexpression of liquid facets. The liquid facets gene encodes the homolog of vertebrate endocytic Epsin, an endocytic adapter protein. In Drosophila, Liquid facets is a core component of the Notch signaling pathway required in the signaling cells for ligand endocytosis and signaling. Why ligand internalization by the signaling cells is essential for signaling is a mystery. The requirement for Liquid facets is a hint at the answer, and the genes identified in this screen provide further clues. Mutant alleles of clathrin heavy chain, Rala, split ends, and auxilin were identified as enhancers. We describe the mutant alleles and mutant phenotypes of Rala and aux. We discuss the relevance of all of these genetic interactions to the function of Liquid facets in Notch signaling.
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Affiliation(s)
- Suk Ho Eun
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA
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Okada Y, Jiang Q, Lemieux M, Jeannotte L, Su L, Zhang Y. Leukaemic transformation by CALM-AF10 involves upregulation of Hoxa5 by hDOT1L. Nat Cell Biol 2006; 8:1017-24. [PMID: 16921363 PMCID: PMC4425349 DOI: 10.1038/ncb1464] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 07/23/2006] [Indexed: 12/16/2022]
Abstract
Chromosomal translocation is a common cause of leukaemia and the most common chromosome translocations found in leukaemia patients involve the mixed lineage leukaemia (MLL) gene. AF10 is one of more than 30 MLL fusion partners in leukaemia. We have recently demonstrated that the H3K79 methyltransferase hDOT1L contributes to MLL-AF10-mediated leukaemogenesis through its interaction with AF10 (ref. 5). In addition to MLL, AF10 has also been reported to fuse to CALM (clathrin-assembly protein-like lymphoid-myeloid) in patients with T-cell acute lymphoblastic leukaemia (T-ALL) and acute myeloid leukaemia (AML). Here, we analysed the molecular mechanism of leukaemogenesis by CALM-AF10. We demonstrate that CALM-AF10 fusion is both necessary and sufficient for leukaemic transformation. Additionally, we provide evidence that hDOT1L has an important role in the transformation process. hDOT1L contributes to CALM-AF10-mediated leukaemic transformation by preventing nuclear export of CALM-AF10 and by upregulating the Hoxa5 gene through H3K79 methylation. Thus, our study establishes CALM-AF10 fusion as a cause of leukaemia and reveals that mistargeting of hDOT1L and upregulation of Hoxa5 through H3K79 methylation is the underlying mechanism behind leukaemia caused by CALM-AF10 fusion.
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Affiliation(s)
- Yuki Okada
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
| | - Qi Jiang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
- Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
| | - Margot Lemieux
- Centre de Recherche de L’Hotel-Dieu de Quebec, 9 rue McMahon, Quebec, QC G1R 2J6, Canada
| | - Lucie Jeannotte
- Centre de Recherche de L’Hotel-Dieu de Quebec, 9 rue McMahon, Quebec, QC G1R 2J6, Canada
| | - Lishan Su
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
- Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
| | - Yi Zhang
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599–7295, USA
- Correspondence should be addressed to Y.Z. ()
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Neuhaus EM, Mashukova A, Barbour J, Wolters D, Hatt H. Novel function of β-arrestin2 in the nucleus of mature spermatozoa. J Cell Sci 2006; 119:3047-56. [PMID: 16820410 DOI: 10.1242/jcs.03046] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A growing number of proteins originally found in endocytic structures of the plasma membrane appear to be able to traffic into the nucleus, but the cellular function of this translocation remains unclear. We have found that β-arrestin2, which typically shows a cytoplasmic localization owing to constitutive nuclear export, appears in the nucleus after stimulation of the G-protein-coupled odorant receptor hOR17-4. In the nucleus, β-arrestin2 was involved in transcriptional regulation as shown by a Gal4-based transactivation assay. Moreover, we discovered that β-arrestin2 and hOR17-4, a receptor known to have a role in sperm-egg communication, colocalize in the midpiece of mature human spermatozoa. Stimulation of hOR17-4 in spermatozoa induced PKA-dependent translocation of β-arrestin2 to the nucleus and nuclear accumulation of phosphorylated MAPKs. Analysis of the interaction partners of β-arrestin2 indicates that odorant receptor signaling in spermatozoa may be important for the regulation of gene expression during the early processes of fertilization.
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Affiliation(s)
- Eva M Neuhaus
- Department of Cell Physiology, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
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50
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Li YC, Hu XQ, Zhang KY, Guo J, Hu ZY, Tao SX, Xiao LJ, Wang QZ, Han CS, Liu YX. Afaf, a novel vesicle membrane protein, is related to acrosome formation in murine testis. FEBS Lett 2006; 580:4266-73. [PMID: 16831425 DOI: 10.1016/j.febslet.2006.06.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 05/12/2006] [Accepted: 06/07/2006] [Indexed: 01/02/2023]
Abstract
As a cell-specific organelle, acrosome (Acr) and its formation are an important event for spermiogenesis. However, the Acr formation is far more complicated than has been proposed. In this study, we have cloned a novel membrane protein Afaf (Acr formation associated factor) that was expressed abundantly in the round spermatids, localized in the inner and outer membrane of forming Acrs, and declined in the maturing Acrs. In the transfected Hela cells, Afaf protein was localized in the plasma membrane, EEA1-positive early endosomes (EEs) and occasionally in the nuclei. Therefore, we propose that EEs and plasma membrane may be also directly involved in the Acr biogenesis.
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Affiliation(s)
- Yin-Chuan Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, PR China
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