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Longo F, De Ritis D, Miluzio A, Fraticelli D, Baets J, Scarlato M, Santorelli FM, Biffo S, Maltecca F. Assessment of Sacsin Turnover in Patients With ARSACS: Implications for Molecular Diagnosis and Pathogenesis. Neurology 2021; 97:e2315-e2327. [PMID: 34649874 PMCID: PMC8665432 DOI: 10.1212/wnl.0000000000012962] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 10/07/2021] [Indexed: 11/15/2022] Open
Abstract
Background and Objectives Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by variations in SACS gene encoding sacsin, a huge multimodular protein of unknown function. More than 200 SACS variations have been described worldwide to date. Because ARSACS presents phenotypic variability, previous empirical studies attempted to correlate the nature and position of SACS variations with the age at onset or with disease severity, although not considering the effect of the various variations on protein stability. In this work, we studied genotype-phenotype correlation in ARSACS at a functional level. Methods We analyzed a large set of skin fibroblasts derived from patients with ARSACS, including both new and already published cases, carrying variations of different types affecting diverse domains of the protein. Results We found that sacsin is almost absent in patients with ARSACS, regardless of the nature of the variation. As expected, we did not detect sacsin in patients with truncating variations. We found it strikingly reduced or absent also in compound heterozygotes carrying diverse missense variations. In this case, we excluded SACS mRNA decay, defective translation, or faster posttranslational degradation as possible causes of protein reduction. Conversely, our results demonstrate that nascent mutant sacsin protein undergoes cotranslational ubiquitination and degradation. Discussion Our results provide a mechanistic explanation for the lack of genotype-phenotype correlation in ARSACS. We also propose a new and unambiguous criterion for ARSACS diagnosis that is based on the evaluation of sacsin level. Last, we identified preemptive degradation of a mutant protein as a novel cause of a human disease.
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Affiliation(s)
- Fabiana Longo
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy
| | - Daniele De Ritis
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy
| | - Annarita Miluzio
- Istituto Nazionale di Genetica Molecolare, INGM, "Romeo ed Enrica Invernizzi", Milan, Italy
| | - Davide Fraticelli
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy
| | - Jonathan Baets
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerpen, Belgium
| | - Marina Scarlato
- Department of Neurology, Ospedale San Raffaele, Milan, Italy
| | | | - Stefano Biffo
- Istituto Nazionale di Genetica Molecolare, INGM, "Romeo ed Enrica Invernizzi", Milan, Italy.,Department of Biosciences, University of Milan, Milan, Italy
| | - Francesca Maltecca
- Mitochondrial Dysfunctions in Neurodegeneration Unit, Ospedale San Raffaele, Milan, Italy .,Università Vita-Salute San Raffaele, Milan, Italy
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Manfrini N, Ricciardi S, Alfieri R, Ventura G, Calamita P, Favalli A, Biffo S. Ribosome profiling unveils translational regulation of metabolic enzymes in primary CD4 + Th1 cells. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 109:103697. [PMID: 32330465 DOI: 10.1016/j.dci.2020.103697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/06/2020] [Accepted: 04/06/2020] [Indexed: 05/22/2023]
Abstract
The transition from a naïve to an effector T cell is an essential event that requires metabolic reprogramming. We have recently demonstrated that the rapid metabolic changes that occur following stimulation of naïve T cells require the translation of preexisting mRNAs. Here, we provide evidence that translation regulates the metabolic asset of effector T cells. By performing ribosome profiling in human CD4+ Th1 cells, we show that the metabolism of glucose, fatty acids and pentose phosphates is regulated at the translational level. In Th1 cells, each pathway has at least one enzyme regulated at the translational level and selected enzymes have high translational efficiencies. mRNA expression does not predict protein expression. For instance, PKM2 mRNA is equally present in naïve T and Th1 cells, but the protein is abundant only in Th1. 5'-untranslated regions (UTRs) may partly account for this regulation. Overall we suggest that immunometabolism is controlled by translation.
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Affiliation(s)
- Nicola Manfrini
- INGM, National Institute of Molecular Genetics, "Fondazione Romeo ed Enrica Invernizzi", Milano, Italy; Department of Biological Sciences, University of Milan, Milan, Italy
| | - Sara Ricciardi
- INGM, National Institute of Molecular Genetics, "Fondazione Romeo ed Enrica Invernizzi", Milano, Italy; Department of Biological Sciences, University of Milan, Milan, Italy
| | - Roberta Alfieri
- INGM, National Institute of Molecular Genetics, "Fondazione Romeo ed Enrica Invernizzi", Milano, Italy
| | - Gabriele Ventura
- Department of Biological Sciences, University of Milan, Milan, Italy
| | - Piera Calamita
- INGM, National Institute of Molecular Genetics, "Fondazione Romeo ed Enrica Invernizzi", Milano, Italy; Department of Biological Sciences, University of Milan, Milan, Italy
| | - Andrea Favalli
- Department of Biological Sciences, University of Milan, Milan, Italy
| | - Stefano Biffo
- INGM, National Institute of Molecular Genetics, "Fondazione Romeo ed Enrica Invernizzi", Milano, Italy; Department of Biological Sciences, University of Milan, Milan, Italy.
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Li Z, Lim SK, Liang X, Lim YP. The transcriptional coactivator WBP2 primes triple-negative breast cancer cells for responses to Wnt signaling via the JNK/Jun kinase pathway. J Biol Chem 2018; 293:20014-20028. [PMID: 30442712 PMCID: PMC6311518 DOI: 10.1074/jbc.ra118.005796] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/29/2018] [Indexed: 12/17/2022] Open
Abstract
The transcriptional coactivator WW domain-binding protein 2 (WBP2) is an emerging oncogene and serves as a node between the signaling protein Wnt and other signaling molecules and pathways, including epidermal growth factor receptor, estrogen receptor/progesterone receptor, and the Hippo pathway. The upstream regulation of WBP2 is well-studied, but its downstream activity remains unclear. Here, we elucidated WBP2's role in triple-negative breast cancer (TNBC), in which Wnt signaling is predominantly activated. Using RNAi coupled with RNA-Seq and MS analyses to identify Wnt/WBP2- and WBP2-dependent targets in MDA-MB-231 TNBC cells, we found that WBP2 is required for the expression of a core set of genes in Wnt signaling. These included AXIN2, which was essential for Wnt/WBP2-mediated breast cancer growth and migration. WBP2 also regulated a much larger set of genes and proteins independently of Wnt, revealing that WBP2 primes cells to Wnt activity by up-regulating G protein pathway suppressor 1 (GPS1) and TRAF2- and NCK-interacting kinase (TNIK). GPS1 activated the c-Jun N-terminal kinase (JNK)/Jun pathway, resulting in a positive feedback loop with TNIK that mediated Wnt-induced AXIN2 expression. WBP2 promoted TNBC growth by integrating JNK with Wnt signaling, and its expression profoundly influenced the sensitivity of TNBC to JNK/TNIK inhibitors. In conclusion, WBP2 links JNK to Wnt signaling in TNBC. GPS1 and TNIK are constituents of a WBP2-initiated cascade that primes responses to Wnt ligands and are also important for TNBC biology. We propose that WBP2 is a potential drug target for JNK/TNIK-based precision medicine for managing TNBC.
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Affiliation(s)
- Zilin Li
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Shen Kiat Lim
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Xu Liang
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Yoon Pin Lim
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545,; the National University Cancer Institute, Singapore 119082, and; the NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456.
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Nagiah S, Phulukdaree A, Chuturgoon AA. Lon protease and eiF2α are involved in acute, but not prolonged, antiretroviral induced stress response in HepG2 cells. Chem Biol Interact 2016; 252:82-6. [PMID: 27041070 DOI: 10.1016/j.cbi.2016.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/26/2016] [Accepted: 03/20/2016] [Indexed: 11/28/2022]
Abstract
Lon protease, an ATP dependent mitochondrial protease, is important in mitochondrial protein maintenance. Disruption of protein homeostasis and mitochondrial dysfunction is associated with lipodystrophy, metabolic syndrome and accelerated aging, and are commonly observed in patients on long term antiretroviral therapy. Sirtuin 3 (SIRT3) is a post-translational regulator of Lon and regulates antioxidant response. We previously showed the nucleoside analogues (NRTIs), Zidovudine (AZT; 7.1 μM), Stavudine (d4T; 4 μM), and Tenofovir (TFV; 1.2 μM) induced oxidative stress and mitochondrial dysfunction in human hepatoma (HepG2) cells at 24 h (h) and 120 h. We conducted a mitochondrial proteomic assessment of homeostasis in the same model, using the same NRTIs. Protein expression of Lon, SIRT3, heat shock protein (HSP) 60, phospho-eukaryotic translation initiation factor 2α (p-eIF2α; Ser51) and phospho-c-jun N-terminal kinase (p-JNK; Thr183/Tyr185) were quantified by western blots. The data showed all stress responses were significantly increased in HepG2 cells by all antiretroviral drugs at 24 h (p < 0.0001); however, at 120 h, a significant depletion in the ATP-dependent proteins Lon (p = 0.00013) and HSP60 (p < 0.0001) was observed. Proteins initiated by endoplasmic reticulum stress: p-eIF2α (p = 0.001) and p-JNK (p = 0.0029), were significantly reduced following prolonged treatment. SIRT3 was maintained at elevated levels in the treated cells following prolonged exposure (p < 0.001). We conclude that the ATP dependent proteins are more relevant to acute toxicity, while SIRT3 confers protection over prolonged periods of toxicity.
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Affiliation(s)
- Savania Nagiah
- 3rd Floor George Campbell Building, Discipline of Medical Biochemistry, Howard College, University of KwaZulu Natal, King George Avenue, Durban, 4041, South Africa.
| | - Alisa Phulukdaree
- Department of Physiology, School of Medicine, Prinshof Campus, Dr Savage Road, 0083, Prinshof, Pretoria, Gauteng, South Africa.
| | - Anil A Chuturgoon
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu Natal, Durban, South Africa; 3rd Floor George Campbell Building, Discipline of Medical Biochemistry, Howard College, University of KwaZulu Natal, King George Avenue, Durban, 4041, South Africa.
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Gandin V, Topisirovic I. Co-translational mechanisms of quality control of newly synthesized polypeptides. ACTA ACUST UNITED AC 2014; 2:e28109. [PMID: 26779401 PMCID: PMC4705825 DOI: 10.4161/trla.28109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/30/2013] [Accepted: 02/04/2014] [Indexed: 01/23/2023]
Abstract
During protein synthesis, nascent polypeptides emerge from ribosomes to fold into functional proteins. Misfolding of newly synthesized polypeptides (NSPs) at this stage leads to their aggregation. These misfolded NSPs must be expediently cleared to circumvent the deleterious effects of protein aggregation on cell physiology. To this end, a sizable portion of NSPs are ubiquitinated and rapidly degraded by the proteasome. This suggests the existence of co-translational mechanisms that play a pivotal role in the quality control of NSPs. It is generally thought that ribosomes play a central role in this process. During mRNA translation, ribosomes sense errors that lead to the accumulation of aberrant polypeptides, and serve as a hub for protein complexes that are required for optimal folding and/or proteasome-dependent degradation of misfolded polypeptides. In this review, we discuss recent findings that shed light on the molecular underpinnings of the co-translational quality control of NSPs.
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Affiliation(s)
- Valentina Gandin
- Lady Davis Institute for Medical Research; Sir Mortimer B. Davis-Jewish General Hospital; Montréal, QC Canada; Department of Oncology; McGill University; Montréal, QC Canada
| | - Ivan Topisirovic
- Lady Davis Institute for Medical Research; Sir Mortimer B. Davis-Jewish General Hospital; Montréal, QC Canada; Department of Oncology; McGill University; Montréal, QC Canada
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Pola C, Formenti SC, Schneider RJ. Vitronectin–αvβ3 Integrin Engagement Directs Hypoxia-Resistant mTOR Activity and Sustained Protein Synthesis Linked to Invasion by Breast Cancer Cells. Cancer Res 2013; 73:4571-8. [DOI: 10.1158/0008-5472.can-13-0218] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Degradation of newly synthesized polypeptides by ribosome-associated RACK1/c-Jun N-terminal kinase/eukaryotic elongation factor 1A2 complex. Mol Cell Biol 2013; 33:2510-26. [PMID: 23608534 DOI: 10.1128/mcb.01362-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Folding of newly synthesized polypeptides (NSPs) into functional proteins is a highly regulated process. Rigorous quality control ensures that NSPs attain their native fold during or shortly after completion of translation. Nonetheless, signaling pathways that govern the degradation of NSPs in mammals remain elusive. We demonstrate that the stress-induced c-Jun N-terminal kinase (JNK) is recruited to ribosomes by the receptor for activated protein C kinase 1 (RACK1). RACK1 is an integral component of the 40S ribosome and an adaptor for protein kinases. Ribosome-associated JNK phosphorylates the eukaryotic translation elongation factor 1A isoform 2 (eEF1A2) on serines 205 and 358 to promote degradation of NSPs by the proteasome. These findings establish a role for a RACK1/JNK/eEF1A2 complex in the quality control of NSPs in response to stress.
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Prolactin and epidermal growth factor stimulate adipophilin synthesis in HC11 mouse mammary epithelial cells via the PI3-kinase/Akt/mTOR pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:987-96. [DOI: 10.1016/j.bbamcr.2012.02.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 02/08/2012] [Accepted: 02/27/2012] [Indexed: 11/19/2022]
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