1
|
Amakura Y, Taguchi YH. Estimation of Metabolic Effects upon Cadmium Exposure during Pregnancy Using Tensor Decomposition. Genes (Basel) 2022; 13:genes13101698. [PMID: 36292583 PMCID: PMC9602417 DOI: 10.3390/genes13101698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/25/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
A simple tensor decomposition model was applied to the liver transcriptome analysis data to elucidate the cause of cadmium-induced gene overexpression. In addition, we estimated the mechanism by which prenatal Cd exposure disrupts insulin metabolism in offspring. Numerous studies have reported on the toxicity of Cd. A liver transcriptome analysis revealed that Cd toxicity induces intracellular oxidative stress and mitochondrial dysfunction via changes in gene expression, which in turn induces endoplasmic reticulum-associated degradation via abnormal protein folding. However, the specific mechanisms underlying these effects remain unknown. In this study, we found that Cd-induced endoplasmic reticulum stress may promote increased expression of tumor necrosis factor-α (TNF-α). Based on the high expression of genes involved in the production of sphingolipids, it was also found that the accumulation of ceramide may induce intracellular oxidative stress through the overproduction of reactive oxygen species. In addition, the high expression of a set of genes involved in the electron transfer system may contribute to oxidative stress. These findings allowed us to identify the mechanisms by which intracellular oxidative stress leads to the phosphorylation of insulin receptor substrate 1, which plays a significant role in the insulin signaling pathway.
Collapse
Affiliation(s)
- Yuki Amakura
- Graduate School of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
| | - Y-h. Taguchi
- Department of Physics, Chuo University, Tokyo 112-8551, Japan
- Correspondence:
| |
Collapse
|
2
|
Singhal SK, Byun JS, Yan T, Yancey R, Caban A, Gil Hernandez S, Bufford S, Hewitt SM, Winfield J, Pradhan JS, Mustkov V, McDonald JA, Pérez-Stable EJ, Napoles AM, Vohra N, De Siervi A, Yates C, Davis MB, Yang M, Tsai YC, Weissman AM, Gardner K. Protein expression of the gp78 E3-ligase predicts poor breast cancer outcome based on race. JCI Insight 2022; 7:157465. [PMID: 35639484 PMCID: PMC9310521 DOI: 10.1172/jci.insight.157465] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/20/2022] [Indexed: 11/17/2022] Open
Abstract
Women of African ancestry suffer higher rates of breast cancer mortality compared to all other groups in the United States. Though the precise reasons for these disparities remain unclear, many recent studies have implicated a role for differences in tumor biology. Using an epitope-validated antibody against the endoplasmic reticulum-associated degradation (ERAD) E3 ubiquitin ligase, gp78, we show that elevated levels of gp78 in patient breast cancer cells predict poor survival. Moreover, high levels of gp78 are associated with poor outcomes in both ER-positive and ER-negative tumors, and breast cancers expressing elevated amounts of gp78 protein are enriched in gene expression pathways that influence cell cycle, metabolism, receptor-mediated signaling, and cell stress response pathways. In multivariate analysis adjusted for subtype and grade, gp78 protein is an independent predictor of poor outcomes in women of African ancestry. Furthermore, gene expression signatures, derived from patients stratified by gp78 protein expression, are strong predictors of recurrence and pathological complete response in retrospective clinical trial data and share many common features with gene sets previously identified to be overrepresented in breast cancers based on race. These findings implicate a prominent role for gp78 in tumor progression and offer new insights into our understanding of racial differences in breast cancer outcomes.
Collapse
Affiliation(s)
- Sandeep K Singhal
- Department of Pathology, University of North Dakota, Grand Forks, United States of America
| | - Jung S Byun
- Intramural Research Program, National Institutes of Minority Health and Health Disparities, Bethesda, United States of America
| | - Tingfen Yan
- Intramural Research Program, National Institutes of Minority Health and Health Disparities, Bethesda, United States of America
| | - Ryan Yancey
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States of America
| | - Ambar Caban
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States of America
| | - Sara Gil Hernandez
- Intramural Research Program, National Institutes of Minority Health and Health Disparities, Bethesda, United States of America
| | - Sediqua Bufford
- Masters of Science Biotechnology, Morehouse School of Medicine, Atlanta, United States of America
| | - Stephen M Hewitt
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, United States of America
| | - Joy Winfield
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States of America
| | - Jaya Sarin Pradhan
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States of America
| | - Vesco Mustkov
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States of America
| | - Jasmine A McDonald
- Department of Epidemiology, Columbia University Medical Center, New York, United States of America
| | - Eliseo J Pérez-Stable
- Intramural Research Program, National Institutes of Minority Health and Health Disparities, Bethesda, United States of America
| | - Anna Maria Napoles
- Intramural Research Program, National Institutes of Minority Health and Health Disparities, Bethesda, United States of America
| | - Nasreen Vohra
- Brody School of Medicine, East Carolina University, Greenville, United States of America
| | - Adriana De Siervi
- Directora del Laboratorio de Oncología Molecular y Nuevos Blancos Terapéut, CONICET, Buenos Aiers, Argentina
| | - Clayton Yates
- Department of Biology and Center for Cancer Research, Tuskegee University, Tuskegee, United States of America
| | - Melissa B Davis
- Department of Surgery (Breast Surgery & Oncology), Weill Cornell Medicine, New York, United States of America
| | - Mei Yang
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, Frederick, United States of America
| | - Yien Che Tsai
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, Frederick, United States of America
| | - Allan M Weissman
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, Frederick, United States of America
| | - Kevin Gardner
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States of America
| |
Collapse
|
3
|
Abu Irqeba A, Ogilvie JM. Di-arginine and FFAT-like motifs retain a subpopulation of PRA1 at ER-mitochondria membrane contact sites. PLoS One 2020; 15:e0243075. [PMID: 33259547 PMCID: PMC7707580 DOI: 10.1371/journal.pone.0243075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 11/14/2020] [Indexed: 11/19/2022] Open
Abstract
Prenylated Rab Acceptor 1 (PRA1/Rabac1) is a four-pass transmembrane protein that has been found to localize to the Golgi and promiscuously associate with a diverse array of Rab GTPases. We have previously identified PRA1 to be among the earliest significantly down-regulated genes in the rd1 mouse model of retinitis pigmentosa, a retinal degenerative disease. Here, we show that an endogenous subpopulation of PRA1 resides within the endoplasmic reticulum (ER) at ER-mitochondria membrane contact sites in cultured mammalian cells. We also demonstrate that PRA1 contains two previously unidentified ER retention/retrieval amino acid sequences on its cytosolic N-terminal region: a membrane distal di-arginine motif and a novel membrane proximal FFAT-like motif. Using a truncation construct that lacks complete Golgi targeting information, we show that mutation of either motif leads to an increase in cell surface localization, while mutation of both motifs exhibits an additive effect. We also present evidence that illustrates that N- or C- terminal addition of a tag to full-length PRA1 leads to differential localization to either the Golgi or reticular ER, phenotypes that do not completely mirror endogenous protein localization. The presence of multiple ER retention motifs on the PRA1 N-terminal region further suggests that it has a functional role within the ER.
Collapse
Affiliation(s)
- Ameair Abu Irqeba
- Department of Biology, Saint Louis University, St. Louis, Missouri, United States of America
- * E-mail: (AAI); (JMO)
| | - Judith Mosinger Ogilvie
- Department of Biology, Saint Louis University, St. Louis, Missouri, United States of America
- * E-mail: (AAI); (JMO)
| |
Collapse
|
4
|
Link between the unfolded protein response and dysregulation of mitochondrial bioenergetics in Alzheimer's disease. Cell Mol Life Sci 2019; 76:1419-1431. [PMID: 30683981 PMCID: PMC6420888 DOI: 10.1007/s00018-019-03009-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/19/2018] [Accepted: 01/09/2019] [Indexed: 12/11/2022]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder affecting more than 47.5 million people worldwide. Metabolic impairments are common hallmarks of AD, and amyloid-β (Aβ) peptide and hyperphosphorylated tau protein—the two foremost histopathological signs of AD—have been implicated in mitochondrial dysfunction. Many neurodegenerative disorders, including AD, show excessive amounts of mis-/unfolded proteins leading to an activation of the unfolded protein response (UPR). In the present study, we aimed to characterize the link between ER stress and bioenergetics defects under normal condition (human SH-SY5Y neuroblastoma cells: control cells) or under pathological AD condition [SH-SY5Y cells overexpressing either the human amyloid precursor protein (APP) or mutant tau (P301L)]. More specifically, we measured UPR gene expression, cell viability, and bioenergetics parameters, such as ATP production and mitochondrial membrane potential (MMP) in basal condition and after an induced ER stress by thapsigargin. We detected highly activated UPR and dysregulated bioenergetics in basal condition in both AD cellular models. Strikingly, acute-induced ER stress increased the activity of the UPR in both AD cellular models, leading to up-regulation of apoptotic pathways, and further dysregulated mitochondrial function.
Collapse
|
5
|
Rosiglitazone rescues human neural stem cells from amyloid-beta induced ER stress via PPARγ dependent signaling. Exp Cell Res 2018; 370:312-321. [DOI: 10.1016/j.yexcr.2018.06.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 06/23/2018] [Accepted: 06/27/2018] [Indexed: 12/15/2022]
|
6
|
Li L, Gao G, Shankar J, Joshi B, Foster LJ, Nabi IR. p38 MAP kinase-dependent phosphorylation of the Gp78 E3 ubiquitin ligase controls ER-mitochondria association and mitochondria motility. Mol Biol Cell 2015; 26:3828-40. [PMID: 26337390 PMCID: PMC4626067 DOI: 10.1091/mbc.e15-02-0120] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/25/2015] [Indexed: 01/13/2023] Open
Abstract
Epitope mapping of the 3F3A mAb identified p38 MAPK phosphorylation of Ser-538 of the E3 ubiquitin ligase Gp78. p38 MAPK phosphorylation of Ser-538 prevents Gp78-dependent mitofusin degradation, mitochondrial fission, and ER–mitochondria association, defining a novel regulatory mechanism of Gp78 activity at the ER–mitochondria interface. Gp78 is an ERAD-associated E3 ubiquitin ligase that induces degradation of the mitofusin mitochondrial fusion proteins and mitochondrial fission. Gp78 is localized throughout the ER; however, the anti-Gp78 3F3A monoclonal antibody (mAb) recognizes Gp78 selectively in mitochondria-associated ER domains. Epitope mapping localized the epitope of 3F3A and a commercial anti-Gp78 mAb to an 8–amino acid motif (533–541) in mouse Gp78 isoform 2 that forms part of a highly conserved 41–amino acid region containing 14-3-3– and WW-binding domains and a p38 MAP kinase (p38 MAPK) consensus site on Ser-538 (S538). 3F3A binds selectively to nonphosphorylated S538 Gp78. Using 3F3A as a reporter, we induced Gp78 S538 phosphorylation by serum starvation and showed it to be mediated by p38 MAPK. Mass spectroscopy analysis of Gp78 phosphopeptides confirmed S538 as a major p38 MAPK phosphorylation site on Gp78. Gp78 S538 phosphorylation limited its ability to induce mitochondrial fission and degrade MFN1 and MFN2 but did not affect in vitro Gp78 ubiquitin E3 ligase activity. Phosphomimetic Gp78 S538D mutation prevented Gp78 promotion of ER–mitochondria interaction, and SB203580 inhibition of p38 MAPK increased ER–mitochondria association. p38 MAPK phosphorylation of Gp78 S538 therefore regulates Gp78-dependent ER–mitochondria association and mitochondria motility.
Collapse
Affiliation(s)
- Lei Li
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Guang Gao
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jay Shankar
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Bharat Joshi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, Centre for High-Throughput Biology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ivan R Nabi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| |
Collapse
|
7
|
Bravo R, Parra V, Gatica D, Rodriguez AE, Torrealba N, Paredes F, Wang ZV, Zorzano A, Hill JA, Jaimovich E, Quest AFG, Lavandero S. Endoplasmic reticulum and the unfolded protein response: dynamics and metabolic integration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 301:215-90. [PMID: 23317820 DOI: 10.1016/b978-0-12-407704-1.00005-1] [Citation(s) in RCA: 411] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is a dynamic intracellular organelle with multiple functions essential for cellular homeostasis, development, and stress responsiveness. In response to cellular stress, a well-established signaling cascade, the unfolded protein response (UPR), is activated. This intricate mechanism is an important means of re-establishing cellular homeostasis and alleviating the inciting stress. Now, emerging evidence has demonstrated that the UPR influences cellular metabolism through diverse mechanisms, including calcium and lipid transfer, raising the prospect of involvement of these processes in the pathogenesis of disease, including neurodegeneration, cancer, diabetes mellitus and cardiovascular disease. Here, we review the distinct functions of the ER and UPR from a metabolic point of view, highlighting their association with prevalent pathologies.
Collapse
Affiliation(s)
- Roberto Bravo
- Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Fairbank M, Huang K, El-Husseini A, Nabi IR. RING finger palmitoylation of the endoplasmic reticulum Gp78 E3 ubiquitin ligase. FEBS Lett 2012; 586:2488-93. [PMID: 22728137 DOI: 10.1016/j.febslet.2012.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 05/30/2012] [Accepted: 06/01/2012] [Indexed: 11/19/2022]
Abstract
Gp78 is an E3 ubiquitin ligase within the endoplasmic reticulum-associated degradation pathway. We show that Flag-tagged gp78 undergoes sulfhydryl cysteine palmitoylation (S-palmitoylation) within the RING finger motif, responsible for its ubiquitin ligase activity. Screening of 19 palmitoyl acyl transferases (PATs) identified five that increased gp78 RING finger palmitoylation. Endoplasmic reticulum (ER)-localized Myc-DHHC6 overexpression promoted the peripheral ER distribution of Flag-gp78 while RING finger mutation and the palmitoylation inhibitor 2-bromopalmitate restricted gp78 to the central ER. Palmitoylation of RING finger cysteines therefore regulates gp78 distribution to the peripheral ER.
Collapse
Affiliation(s)
- Maria Fairbank
- University of British Columbia, Department of Cellular and Physiological Sciences, Vancouver, British Columbia, Canada
| | | | | | | |
Collapse
|
9
|
St-Pierre P, Dang T, Joshi B, Nabi IR. Peripheral endoplasmic reticulum localization of the Gp78 ubiquitin ligase activity. J Cell Sci 2012; 125:1727-37. [PMID: 22328510 DOI: 10.1242/jcs.096396] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Gp78 (also known as AMFR and RNF45) is an E3 ubiquitin ligase that targets proteins for proteasomal degradation through endoplasmic reticulum (ER)-associated degradation (ERAD). In this study, we showed that gp78-mediated ubiquitylation is initiated in the peripheral ER. Substrate monoubiquitylation and gp78 CUE domain integrity restricted substrate to the peripheral ER, where CUE domain interactions and polyubiquitylation reduced gp78 mobility. Derlin-1 and derlin-2, which are involved in the retrotranslocation of ERAD substrates, localized to a central, juxtanuclear ER domain, where polyubiquitylated proteins accumulated upon proteasome inhibition. Transfer of polyubiquitylated substrate to the central ER was dependent on ubiquitin chain elongation and recruitment of the AAA ATPase p97 (also known as VCP). HT-1080 fibrosarcoma cells expressed elevated levels of endogenous gp78, which was associated with segregation of ubiquitylated substrate to the peripheral ER and its polyubiquitin-dependent redistribution to the central ER upon proteasome inhibition. Therefore, the peripheral ER is the site of gp78 ubiquitin ligase activity. Delivery of ubiquitylated substrate to the central ER was regulated by ubiquitin chain elongation and opposing actions of gp78 CUE domain interactions and p97 recruitment.
Collapse
Affiliation(s)
- Pascal St-Pierre
- University of British Columbia, Life Sciences Institute, Vancouver, BC, Canada
| | | | | | | |
Collapse
|
10
|
St Pierre P, Nabi IR. The Gp78 ubiquitin ligase: probing endoplasmic reticulum complexity. PROTOPLASMA 2012; 249 Suppl 1:S11-S18. [PMID: 22045301 DOI: 10.1007/s00709-011-0344-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/17/2011] [Indexed: 05/31/2023]
Abstract
The endoplasmic reticulum (ER) has been classically divided, based on electron microscopy analysis, into parallel ribosome-studded rough ER sheets and a tubular smooth ER network. Recent studies have identified molecular constituents of the ER, the reticulons and DP1, that drive ER tubule formation and whose expression determines expression of ER sheets and tubules and thereby rough and smooth ER. However, segregation of the ER into only two domains remains simplistic and multiple functionally distinct ER domains necessarily exist. In this review, we will discuss the sub-organization of the ER in different domains focusing on the localization and role of the gp78 ubiquitin ligase in the mitochondria-associated smooth ER and on the evidence for a quality control ERAD domain.
Collapse
Affiliation(s)
- Pascal St Pierre
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | | |
Collapse
|
11
|
Fujimoto M, Hayashi T. New Insights into the Role of Mitochondria-Associated Endoplasmic Reticulum Membrane. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:73-117. [DOI: 10.1016/b978-0-12-386033-0.00002-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
12
|
Gilady SY, Bui M, Lynes EM, Benson MD, Watts R, Vance JE, Simmen T. Ero1alpha requires oxidizing and normoxic conditions to localize to the mitochondria-associated membrane (MAM). Cell Stress Chaperones 2010; 15:619-29. [PMID: 20186508 PMCID: PMC3006622 DOI: 10.1007/s12192-010-0174-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 01/21/2010] [Accepted: 01/25/2010] [Indexed: 10/19/2022] Open
Abstract
Protein secretion from the endoplasmic reticulum (ER) requires the enzymatic activity of chaperones and oxidoreductases that fold polypeptides and form disulfide bonds within newly synthesized proteins. The best-characterized ER redox relay depends on the transfer of oxidizing equivalents from molecular oxygen through ER oxidoreductin 1 (Ero1) and protein disulfide isomerase to nascent polypeptides. The formation of disulfide bonds is, however, not the sole function of ER oxidoreductases, which are also important regulators of ER calcium homeostasis. Given the role of human Ero1alpha in the regulation of the calcium release by inositol 1,4,5-trisphosphate receptors during the onset of apoptosis, we hypothesized that Ero1alpha may have a redox-sensitive localization to specific domains of the ER. Our results show that within the ER, Ero1alpha is almost exclusively found on the mitochondria-associated membrane (MAM). The localization of Ero1alpha on the MAM is dependent on oxidizing conditions within the ER. Chemical reduction of the ER environment, but not ER stress in general leads to release of Ero1alpha from the MAM. In addition, the correct localization of Ero1alpha to the MAM also requires normoxic conditions, but not ongoing oxidative phosphorylation.
Collapse
Affiliation(s)
- Susanna Y. Gilady
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G2H7 Canada
| | - Michael Bui
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G2H7 Canada
| | - Emily M. Lynes
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G2H7 Canada
| | - Matthew D. Benson
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G2H7 Canada
| | - Russell Watts
- Group on the Molecular and Cell Biology of Lipids, Department of Medicine, University of Alberta, Edmonton, AB Canada T6G 2S2
| | - Jean E. Vance
- Group on the Molecular and Cell Biology of Lipids, Department of Medicine, University of Alberta, Edmonton, AB Canada T6G 2S2
| | - Thomas Simmen
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G2H7 Canada
| |
Collapse
|
13
|
Joshi B, Li L, Nabi IR. A role for KAI1 in promotion of cell proliferation and mammary gland hyperplasia by the gp78 ubiquitin ligase. J Biol Chem 2010; 285:8830-9. [PMID: 20089858 DOI: 10.1074/jbc.m109.074344] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of gp78, an E3 ubiquitin ligase in endoplasmic reticulum-associated degradation, is associated with tumor malignancy. To study gp78 overexpression in mammary gland development and tumorigenicity, we generated murine mammary tumor virus (MMTV) long terminal repeat-driven gp78 transgenic mice. Embryos carrying the gp78 transgene cassette were implanted in FVB surrogate mothers, and two founders with high copy integration showed elevated gp78 expression at both transcript and protein levels at the virgin stage and at 12 days gestation. Transgenic mammary glands showed increased ductal branching, dense alveolar lobule formation, and secondary terminal end bud development. Bromodeoxyuridine staining showed increased proliferation in hyperplastic ductal regions at the virgin stage and at 12 days gestation compared with wild type mice. Reduced expression of the metastasis suppressor KAI1, a gp78 endoplasmic reticulum-associated degradation substrate, demonstrates that gp78 ubiquitin ligase activity is increased in MMTV-gp78 mammary gland. Similarly, metastatic MDA-435 cells exhibit increased gp78 expression, decreased KAI1 expression, and elevated proliferation compared with nonmetastatic MCF7 cells whose proliferation was enhanced upon knockdown of KAI1. Importantly, stable gp78 knockdown HEK293 cells showed increased KAI1 expression and reduced proliferation that was rescued upon KAI1 knockdown, demonstrating that gp78 regulation of cell proliferation is mediated by KAI1. Mammary tumorigenesis was not observed in repeatedly pregnant MMTV-long terminal repeat-gp78 transgenic mice over a period of 18 months post-birth. Elevated gp78 ubiquitin ligase activity is therefore not sufficient for mammary tumorigenesis. However, the hyperplastic phenotype observed in mammary glands of MMTV-gp78 transgenic mice identifies a novel role for gp78 expression in enhancing mammary epithelial cell proliferation and nontumorigenic ductal outgrowth.
Collapse
Affiliation(s)
- Bharat Joshi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | | |
Collapse
|
14
|
Fairbank M, St-Pierre P, Nabi IR. The complex biology of autocrine motility factor/phosphoglucose isomerase (AMF/PGI) and its receptor, the gp78/AMFR E3 ubiquitin ligase. MOLECULAR BIOSYSTEMS 2009; 5:793-801. [PMID: 19603112 DOI: 10.1039/b820820b] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Phosphoglucose isomerase (PGI) is a glycolytic enzyme that exhibits a dual function as an extracellular cytokine, under the name autocrine motility factor (AMF). Its cell surface receptor, gp78/AMFR, is also localized to the endoplasmic reticulum where it functions as an E3 ubiquitin ligase. Expression of both AMF/PGI and gp78/AMFR is associated with cancer and, in this review, we will discuss various aspects of the biology of this ligand-receptor complex and its role in tumor progression.
Collapse
Affiliation(s)
- Maria Fairbank
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC V6P 5V8, Canada
| | | | | |
Collapse
|
15
|
Vance JE. Phosphatidylserine and phosphatidylethanolamine in mammalian cells: two metabolically related aminophospholipids. J Lipid Res 2008; 49:1377-87. [PMID: 18204094 DOI: 10.1194/jlr.r700020-jlr200] [Citation(s) in RCA: 335] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphatidylserine (PS) and phosphatidylethanolamine (PE) are two aminophospholipids whose metabolism is interrelated. Both phospholipids are components of mammalian cell membranes and play important roles in biological processes such as apoptosis and cell signaling. PS is synthesized in mammalian cells by base-exchange reactions in which polar head groups of preexisting phospholipids are replaced by serine. PS synthase activity resides primarily on mitochondria-associated membranes and is encoded by two distinct genes. Studies in mice in which each gene has been individually disrupted are beginning to elucidate the importance of these two synthases for biological functions in intact animals. PE is made in mammalian cells by two completely independent major pathways. In one pathway, PS is converted into PE by the mitochondrial enzyme PS decarboxylase. In addition, PE is made via the CDP-ethanolamine pathway, in which the final reaction occurs on the endoplasmic reticulum and nuclear envelope. The relative importance of these two pathways of PE synthesis has been investigated in knockout mice. Elimination of either pathway is embryonically lethal, despite the normal activity of the other pathway. PE can also be generated from a base-exchange reaction and by the acylation of lyso-PE. Cellular levels of PS and PE are tightly regulated by the implementation of multiple compensatory mechanisms.
Collapse
Affiliation(s)
- Jean E Vance
- Group on the Molecular and Cell Biology of Lipids and Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
| |
Collapse
|
16
|
Goetz JG, Genty H, St-Pierre P, Dang T, Joshi B, Sauvé R, Vogl W, Nabi IR. Reversible interactions between smooth domains of the endoplasmic reticulum and mitochondria are regulated by physiological cytosolic Ca2+ levels. J Cell Sci 2007; 120:3553-64. [PMID: 17895372 DOI: 10.1242/jcs.03486] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The 3F3A monoclonal antibody to autocrine motility factor receptor (AMFR) labels mitochondria-associated smooth endoplasmic reticulum (ER) tubules. siRNA down-regulation of AMFR expression reduces mitochondria-associated 3F3A labelling. The 3F3A-labelled ER domain does not overlap with reticulon-labelled ER tubules, the nuclear membrane or perinuclear ER markers and only partially overlaps with the translocon component Sec61alpha. Upon overexpression of FLAG-tagged AMFR, 3F3A labelling is mitochondria associated, excluded from the perinuclear ER and co-distributes with reticulon. 3F3A labelling therefore defines a distinct mitochondria-associated ER domain. Elevation of free cytosolic Ca(2+) levels with ionomycin promotes dissociation of 3F3A-labelled tubules from mitochondria and, judged by electron microscopy, disrupts close contacts (<50 nm) between smooth ER tubules and mitochondria. The ER tubule-mitochondria association is similarly disrupted upon thapsigargin-induced release of ER Ca(2+) stores or purinergic receptor stimulation by ATP. The inositol (1,4,5)-trisphosphate [Ins(1,4,5)P(3)] receptor (IP3R) colocalises to 3F3A-labelled mitochondria-associated ER tubules, and conditions that induce ER tubule-mitochondria dissociation disrupt continuity between 3F3A- and IP3R-labelled ER domains. RAS-transformed NIH-3T3 cells have increased basal cytosolic Ca(2+) levels and show dissociation of the 3F3A-labelled, but not IP3R-labelled, ER from mitochondria. Our data indicate that regulation of the ER-mitochondria association by free cytosolic Ca(2+) is a characteristic of smooth ER domains and that multiple mechanisms regulate the interaction between these organelles.
Collapse
Affiliation(s)
- Jacky G Goetz
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver V6T 1Z3, Canada
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
The ER (endoplasmic reticulum) is composed of multiple domains including the nuclear envelope, ribosome-studded rough ER and the SER (smooth ER). The SER can also be functionally segregated into domains that regulate ER-Golgi traffic (transitional ER), ERAD (ER-associated degradation), sterol and lipid biosynthesis and calcium sequestration. The last two, as well as apoptosis, are critically regulated by the close association of the SER with mitochondria. Studies with AMFR (autocrine motility factor receptor) have defined an SER domain whose integrity and mitochondrial association can be modulated by ilimaquinone as well as by free cytosolic calcium levels in the normal physiological range. AMFR is an E3 ubiquitin ligase that targets its ligand directly to the SER via a caveolae/raft-dependent pathway. In the present review, we will address the relationship between the calcium-dependent morphology and mitochondrial association of the SER and its various functional roles in the cell.
Collapse
Affiliation(s)
- J G Goetz
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada
| | | |
Collapse
|
18
|
Lagana A, Goetz JG, Y N, Altschuler Y, Nabi IR. pH-specific sequestration of phosphoglucose isomerase/autocrine motility factor by fibronectin and heparan sulphate. J Cell Sci 2005; 118:4175-85. [PMID: 16141236 DOI: 10.1242/jcs.02538] [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] [Indexed: 01/03/2023] Open
Abstract
Phosphoglucose isomerase (PGI) is a glycolytic enzyme that moonlights as a cytokine under the aliases autocrine motility factor (AMF), neuroleukin and maturation factor. The cytokine function of PGI/AMF targets multiple cell types however mechanisms that regulate and sequester this ubiquitous, circulating cytokine remain largely unidentified. PGI/AMF is shown here to exhibit fibronectin (FN)-dependent cell surface association at both neutral and acid pH. Direct PGI/AMF binding to FN and fluorescence resonance energy transfer (FRET) between PGI/AMF and FN were detected only at pH 5. At neutral pH, the interaction of PGI/AMF with FN is receptor-mediated requiring prior clathrin-dependent endocytosis. PGI/AMF and FN do not co-internalize and PGI/AMF undergoes a second round of endocytosis upon recycling to the plasma membrane indicating that recycling PGI/AMF receptor complexes associate with FN fibrils. Heparan sulphate does not affect cell association of PGI/AMF at neutral pH but enhances the FN-independent cell surface association of PGI/AMF at acid pH identifying two distinct mechanisms for PGI/AMF sequestration under acidic conditions. However, only PGI/AMF sequestration by FN at acid pH was able to stimulate cell motility upon pH neutralization identifying FN as a pH-dependent cytokine trap for PGI/AMF. The multiple ways of cellular association of PGI/AMF may represent acquired mechanisms to regulate and harness the cytokine function of PGI/AMF.
Collapse
Affiliation(s)
- Annick Lagana
- Département de pathologie et biologie cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | | | | | | | | |
Collapse
|