1
|
Sbardella D, Tundo GR, Mecchia A, Palumbo C, Atzori MG, Levati L, Boccaccini A, Caccuri AM, Cascio P, Lacal PM, Graziani G, Varano M, Coletta M, Parravano M. A novel and atypical NF-KB pro-inflammatory program regulated by a CamKII-proteasome axis is involved in the early activation of Muller glia by high glucose. Cell Biosci 2022; 12:108. [PMID: 35842713 PMCID: PMC9287993 DOI: 10.1186/s13578-022-00839-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 06/28/2022] [Indexed: 11/29/2022] Open
Abstract
Background Diabetic retinopathy (DR) is a microvascular complication of diabetes with a heavy impact on the quality of life of subjects and with a dramatic burden for health and economic systems on a global scale. Although the pathogenesis of DR is largely unknown, several preclinical data have pointed out to a main role of Muller glia (MG), a cell type which spans across the retina layers providing nourishment and support for Retina Ganglion Cells (RGCs), in sensing hyper-glycemia and in acquiring a pro-inflammatory polarization in response to this insult. Results By using a validated experimental model of DR in vitro, rMC1 cells challenged with high glucose, we uncovered the induction of an early (within minutes) and atypical Nuclear Factor-kB (NF-kB) signalling pathway regulated by a calcium-dependent calmodulin kinase II (CamKII)-proteasome axis. Phosphorylation of proteasome subunit Rpt6 (at Serine 120) by CamKII stimulated the accelerated turnover of IkBα (i.e., the natural inhibitor of p65-50 transcription factor), regardless of the phosphorylation at Serine 32 which labels canonical NF-kB signalling. This event allowed the p65-p50 heterodimer to migrate into the nucleus and to induce transcription of IL-8, Il-1β and MCP-1. Pharmacological inhibition of CamKII as well as proteasome inhibition stopped this pro-inflammatory program, whereas introduction of a Rpt6 phospho-dead mutant (Rpt6-S120A) stimulated a paradoxical effect on NF-kB probably through the activation of a compensatory mechanism which may involve phosphorylation of 20S α4 subunit. Conclusions This study introduces a novel pathway of MG activation by high glucose and casts some light on the biological relevance of proteasome post-translational modifications in modulating pathways regulated through targeted proteolysis. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00839-x. High glucose quickly induces an atypical NF-kB pro-inflammatory program. CamKII phosphorylation of Rpt6 subunit of the proteasome stimulates IkBα turnover and p65-p50 release. Inhibition of either CamkII or proteasome blocks this pathway.
Collapse
|
2
|
Zerfas BL, Coleman RA, Salazar-Chaparro AF, Macatangay NJ, Trader DJ. Fluorescent Probes with Unnatural Amino Acids to Monitor Proteasome Activity in Real-Time. ACS Chem Biol 2020; 15:2588-2596. [PMID: 32786259 PMCID: PMC8319958 DOI: 10.1021/acschembio.0c00634] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The proteasome is an essential protein complex that, when dysregulated, can result in various diseases in eukaryotic cells. As such, understanding the enzymatic activity of the proteasome and what can alter it is crucial to elucidating its roles in these diseases. This can be done effectively by using activity-based fluorescent substrate probes, of which there are many commercially available that target the individual protease-like subunits in the 20S CP of the proteasome. Unfortunately, these probes have not displayed appropriate characteristics for their use in live cell-based assays. In the work presented here, we have developed a set of probes which have shown improved fluorescence properties and selectivity toward the proteasome compared to other cellular proteases. By including unnatural amino acids, we have found probes which can be utilized in various applications, including monitoring the effects of small molecule stimulators of the proteasome in live cells and comparing the relative proteasome activity across different cancer cell types. In future studies, we expect the fluorescent probes presented here will serve as tools to support the discovery and characterization of small molecule modulators of proteasome activity.
Collapse
Affiliation(s)
- Breanna L. Zerfas
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Rachel A. Coleman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Andres F. Salazar-Chaparro
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Nathaniel J. Macatangay
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Darci J. Trader
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| |
Collapse
|
3
|
Coleman RA, Trader DJ. Methods to Discover and Evaluate Proteasome Small Molecule Stimulators. Molecules 2019; 24:molecules24122341. [PMID: 31242677 PMCID: PMC6630500 DOI: 10.3390/molecules24122341] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/18/2019] [Accepted: 06/22/2019] [Indexed: 11/25/2022] Open
Abstract
Protein accumulation has been identified as a characteristic of many degenerative conditions, such as neurodegenerative diseases and aging. In most cases, these conditions also present with diminished protein degradation. The ubiquitin-proteasome system (UPS) is responsible for the degradation of the majority of proteins in cells; however, the activity of the proteasome is reduced in these disease states, contributing to the accumulation of toxic protein. It has been hypothesized that proteasome activity, both ubiquitin-dependent and -independent, can be chemically stimulated to reduce the load of protein in diseased cells. Several methods exist to identify and characterize stimulators of proteasome activity. In this review, we detail the ways in which protease activity can be enhanced and analyze the biochemical and cellular methods of identifying stimulators of both the ubiquitin-dependent and -independent proteasome activities.
Collapse
Affiliation(s)
- Rachel A Coleman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 610 Purdue Mall, West Lafayette, IN 47907, USA.
| | - Darci J Trader
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 610 Purdue Mall, West Lafayette, IN 47907, USA.
| |
Collapse
|
4
|
Zerfas BL, Trader DJ. Monitoring the Immunoproteasome in Live Cells Using an Activity-Based Peptide-Peptoid Hybrid Probe. J Am Chem Soc 2019; 141:5252-5260. [PMID: 30862160 DOI: 10.1021/jacs.8b12873] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Activity-based probes have greatly improved our understanding of the intrinsic roles and expression levels of various proteins within cells. To be useful in live cells, probes must be cell permeable and provide a read-out that can be measured without disrupting the cells or the activity of the target. Unfortunately, probes for the various forms of the proteasome that can be utilized in intact cells are limited; commercially available probes are most effectively used with purified protein or cell lysate. The proteasome, both the 26S and various isoforms of the 20S CP, is an important target with reported roles in cancer, autoimmune disorders, and neurodegenerative diseases. Here, we present the development of a selective probe for the immunoproteasome, a specialized isoform of the 20S proteasome, that becomes expressed in cells that encounter an inflammatory signal. Using a one-bead, one-compound library of small peptides, we discovered a trimer sequence efficiently cleaved by the immunoproteasome with significant selectivity over the standard proteasome. Upon conjugating this sequence to rhodamine 110 and a peptoid, we generated a probe with a considerable improvement in sensitivity compared to that of current aminomethylcoumarin-based proteasome probes. Importantly, our probe was capable of labeling immunoproteasome-expressing cells while maintaining its selectivity over other cellular proteases in live cell cultures. We anticipate this probe to find wide utility for those that wish to study the immunoproteasome's activity in a variety of cell lines and to be used as a reporter to discover small molecules that can perturb the activity of this proteasome isoform.
Collapse
Affiliation(s)
- Breanna L Zerfas
- Department of Medicinal Chemistry and Molecular Pharmacology , Purdue University , 575 West Stadium Avenue , West Lafayette , Indiana 47907 , United States
| | - Darci J Trader
- Department of Medicinal Chemistry and Molecular Pharmacology , Purdue University , 575 West Stadium Avenue , West Lafayette , Indiana 47907 , United States
| |
Collapse
|
5
|
Coleman RA, Trader DJ. Development and Application of a Sensitive Peptide Reporter to Discover 20S Proteasome Stimulators. ACS COMBINATORIAL SCIENCE 2018; 20:269-276. [PMID: 29553711 DOI: 10.1021/acscombsci.7b00193] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To attenuate an overabundance of cellular protein, it has been hypothesized that the 20S core particle (20S CP) of the proteasome can be chemically stimulated to degrade proteins into nontoxic peptides more quickly. Screening for small molecule 20S CP stimulators is typically performed with a reporter peptide composed of four amino acids and a coumarin group that is released upon proteasome-mediated hydrolysis to generate a fluorescent signal. Screening with this small reporter can lead to false negatives because the reporter peptide is rapidly turned-over without stimulation. To improve the screening for 20S CP stimulators, we have developed a peptide FRET reporter nearly four times more sensitive to stimulation but still amenable for high throughput screening. Through application of our FRET reporter, we have discovered two 20S CP gate-opening stimulators and also a molecule that elicits its mechanism of action through an interaction with a 20S CP active site.
Collapse
Affiliation(s)
- Rachel A. Coleman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Darci J. Trader
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, Indiana 47907, United States
| |
Collapse
|
6
|
Tomasello MF, Nardon C, Lanza V, Di Natale G, Pettenuzzo N, Salmaso S, Milardi D, Caliceti P, Pappalardo G, Fregona D. New comprehensive studies of a gold(III) Dithiocarbamate complex with proven anticancer properties: Aqueous dissolution with cyclodextrins, pharmacokinetics and upstream inhibition of the ubiquitin-proteasome pathway. Eur J Med Chem 2017. [PMID: 28651154 DOI: 10.1016/j.ejmech.2017.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The gold(III)-dithiocarbamate complex AuL12 (dibromo [ethyl-N-(dithiocarboxy-kS,kS')-N-methylglycinate] gold(III)), is endowed with promising in vitro/in vivo antitumor activity and toxicological profile. Here, we report our recent strategies to improve its water solubility and stability under physiological conditions along with our efforts for unravelling its tangled mechanism of action. We used three types of α-cyclodextrins (CDs), namely β-CD, Me-β-CD and HP-β-CD to prepare aqueous solutions of AuL12. The ability of these natural oligosaccharide carriers to enhance water solubility of hydrophobic compounds, allowed drug stability of AuL12 to be investigated. Moreover, pharmacokinetic experiments were first carried out for a gold(III) coordination compound, after i.v. injection of the nanoformulation AuL12/HP-β-CD to female mice. The gold content in the blood samples was detected at scheduled times by AAS (atomic absorption spectrometry) analysis, highlighting a fast biodistribution with a tβ1/2 of few minutes and a slow escretion (tα1/2 of 14.3 h). The in vitro cytotoxic activity of AuL12 was compared with the AuL12/HP-β-CD mixture against a panel of three human tumor cell lines (i.e., HeLa, KB and MCF7). Concerning the mechanism of action, we previously reported the proteasome-inhibitory activity of some our gold(III)-based compounds. In this work, we moved from the proteasome target to upstream of the important ubiquitin-proteasome pathway, testing the effects of AuL12 on the polyubiquitination reactions involving the Ub-activating (E1) and -conjugating (E2) enzymes.
Collapse
Affiliation(s)
- Marianna F Tomasello
- IBB-CNR, Istituto di Biostrutture e Bioimmagini, Sede Secondaria di Catania, Via Paolo Gaifami, 18 - 95126, Catania, Italy
| | - Chiara Nardon
- Università degli Studi di Padova, Dipartimento di Scienze Chimiche, Via F. Marzolo 1, 35131, Padova, Italy
| | - Valeria Lanza
- IBB-CNR, Istituto di Biostrutture e Bioimmagini, Sede Secondaria di Catania, Via Paolo Gaifami, 18 - 95126, Catania, Italy
| | - Giuseppe Di Natale
- IBB-CNR, Istituto di Biostrutture e Bioimmagini, Sede Secondaria di Catania, Via Paolo Gaifami, 18 - 95126, Catania, Italy
| | - Nicolò Pettenuzzo
- Università degli Studi di Padova, Dipartimento di Scienze Chimiche, Via F. Marzolo 1, 35131, Padova, Italy
| | - Stefano Salmaso
- Università degli Studi di Padova, Dipartimento di Scienze Farmaceutiche, Via F. Marzolo 5, 35131, Padova, Italy
| | - Danilo Milardi
- IBB-CNR, Istituto di Biostrutture e Bioimmagini, Sede Secondaria di Catania, Via Paolo Gaifami, 18 - 95126, Catania, Italy
| | - Paolo Caliceti
- Università degli Studi di Padova, Dipartimento di Scienze Farmaceutiche, Via F. Marzolo 5, 35131, Padova, Italy
| | - Giuseppe Pappalardo
- IBB-CNR, Istituto di Biostrutture e Bioimmagini, Sede Secondaria di Catania, Via Paolo Gaifami, 18 - 95126, Catania, Italy.
| | - Dolores Fregona
- Università degli Studi di Padova, Dipartimento di Scienze Chimiche, Via F. Marzolo 1, 35131, Padova, Italy.
| |
Collapse
|
7
|
Santoro AM, Monaco I, Attanasio F, Lanza V, Pappalardo G, Tomasello MF, Cunsolo A, Rizzarelli E, De Luigi A, Salmona M, Milardi D. Copper(II) ions affect the gating dynamics of the 20S proteasome: a molecular and in cell study. Sci Rep 2016; 6:33444. [PMID: 27633879 PMCID: PMC5025780 DOI: 10.1038/srep33444] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/09/2016] [Indexed: 12/14/2022] Open
Abstract
Due to their altered metabolism cancer cells are more sensitive to proteasome inhibition or changes of copper levels than normal cells. Thus, the development of copper complexes endowed with proteasome inhibition features has emerged as a promising anticancer strategy. However, limited information is available about the exact mechanism by which copper inhibits proteasome. Here we show that Cu(II) ions simultaneously inhibit the three peptidase activities of isolated 20S proteasomes with potencies (IC50) in the micromolar range. Cu(II) ions, in cell-free conditions, neither catalyze red-ox reactions nor disrupt the assembly of the 20S proteasome but, rather, promote conformational changes associated to impaired channel gating. Notably, HeLa cells grown in a Cu(II)-supplemented medium exhibit decreased proteasome activity. This effect, however, was attenuated in the presence of an antioxidant. Our results suggest that if, on one hand, Cu(II)-inhibited 20S activities may be associated to conformational changes that favor the closed state of the core particle, on the other hand the complex effect induced by Cu(II) ions in cancer cells is the result of several concurring events including ROS-mediated proteasome flooding, and disassembly of the 26S proteasome into its 20S and 19S components.
Collapse
Affiliation(s)
- Anna Maria Santoro
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
| | - Irene Monaco
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
- Fondazione RiMed, Via Bandiera 11, 90133, Palermo, Italy
| | - Francesco Attanasio
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
| | - Valeria Lanza
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
| | - Giuseppe Pappalardo
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
| | - Marianna Flora Tomasello
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
| | - Alessandra Cunsolo
- Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 6, 95125 Catania, Italy
| | - Enrico Rizzarelli
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
- Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 6, 95125 Catania, Italy
| | - Ada De Luigi
- IRCCS-Istituto di Ricerche Farmacologiche “Mario Negri”, Via Giuseppe La Masa 19, 20156, Milano, Italy
| | - Mario Salmona
- IRCCS-Istituto di Ricerche Farmacologiche “Mario Negri”, Via Giuseppe La Masa 19, 20156, Milano, Italy
| | - Danilo Milardi
- Istituto di Biostrutture e Bioimmagini - CNR Sede di Catania, Via P. Gaifami, 9- 95126 Catania, Italy
| |
Collapse
|
8
|
Furfaro AL, Piras S, Domenicotti C, Fenoglio D, De Luigi A, Salmona M, Moretta L, Marinari UM, Pronzato MA, Traverso N, Nitti M. Role of Nrf2, HO-1 and GSH in Neuroblastoma Cell Resistance to Bortezomib. PLoS One 2016; 11:e0152465. [PMID: 27023064 PMCID: PMC4811586 DOI: 10.1371/journal.pone.0152465] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 03/15/2016] [Indexed: 01/10/2023] Open
Abstract
The activation of Nrf2 has been demonstrated to play a crucial role in cancer cell resistance to different anticancer therapies. The inhibition of proteasome activity has been proposed as a chemosensitizing therapy but the activation of Nrf2 could reduce its efficacy. Using the highly chemoresistant neuroblastoma cells HTLA-230, here we show that the strong reduction in proteasome activity, obtained by using low concentration of bortezomib (BTZ, 2.5 nM), fails in reducing cell viability. BTZ treatment favours the binding of Nrf2 to the ARE sequences in the promoter regions of target genes such as heme oxygenase 1 (HO-1), the modulatory subunit of γ-glutamylcysteine ligase (GCLM) and the transporter for cysteine (x-CT), enabling their transcription. GSH level is also increased after BTZ treatment. The up-regulation of Nrf2 target genes is responsible for cell resistance since HO-1 silencing and GSH depletion synergistically decrease BTZ-treated cell viability. Moreover, cell exposure to all-trans-Retinoic acid (ATRA, 3 μM) reduces the binding of Nrf2 to the ARE sequences, decreases HO-1 induction and lowers GSH level increasing the efficacy of bortezomib. These data suggest the role of Nrf2, HO-1 and GSH as molecular targets to improve the efficacy of low doses of bortezomib in the treatment of malignant neuroblastoma.
Collapse
Affiliation(s)
- A. L. Furfaro
- Giannina Gaslini Institute, Via Gerolamo Gaslini 5, 16147, Genova, Italy
| | - S. Piras
- Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132, Genova, Italy
| | - C. Domenicotti
- Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132, Genova, Italy
| | - D. Fenoglio
- Center of Excellence for Biomedical Research, Department of Internal Medicine, University of Genoa, 16132, Genova, Italy
| | - A. De Luigi
- IRCCS-Istituto di Ricerche Farmacologiche “Mario Negri”, Via Giuseppe La Masa 19, 20156, Milano, Italy
| | - M. Salmona
- IRCCS-Istituto di Ricerche Farmacologiche “Mario Negri”, Via Giuseppe La Masa 19, 20156, Milano, Italy
| | - L. Moretta
- Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Roma, Italy
| | - U. M. Marinari
- Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132, Genova, Italy
| | - M. A. Pronzato
- Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132, Genova, Italy
| | - N. Traverso
- Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132, Genova, Italy
| | - M. Nitti
- Department of Experimental Medicine, University of Genoa, Via L.B. Alberti 2, 16132, Genova, Italy
- * E-mail:
| |
Collapse
|
9
|
Stacer AC, Wang H, Fenner J, Dosch JS, Salomonnson A, Luker KE, Luker GD, Rehemtulla A, Ross BD. Imaging Reporters for Proteasome Activity Identify Tumor- and Metastasis-Initiating Cells. Mol Imaging 2015. [DOI: 10.2310/7290.2015.00016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Amanda C. Stacer
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Hanxiao Wang
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Joseph Fenner
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Joseph S. Dosch
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Anna Salomonnson
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Kathryn E. Luker
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Gary D. Luker
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Alnawaz Rehemtulla
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| | - Brian D. Ross
- From the Center for Molecular Imaging, Department of Radiology and Departments of Radiation Oncology, Biomedical Engineering, Microbiology and Immunology, and Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI
| |
Collapse
|
10
|
Measuring activity in the ubiquitin-proteasome system: from large scale discoveries to single cells analysis. Cell Biochem Biophys 2014; 67:75-89. [PMID: 23686610 DOI: 10.1007/s12013-013-9621-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The ubiquitin-proteasome system (UPS) is the primary pathway responsible for the recognition and degradation of misfolded, damaged, or tightly regulated proteins in addition to performing essential roles in DNA repair, cell cycle regulation, cell migration, and the immune response. While traditional biochemical techniques have proven useful in the identification of key proteins involved in this pathway, the implementation of novel reporters responsible for measuring enzymatic activity of the UPS has provided valuable insight into the effectiveness of therapeutics and role of the UPS in various human diseases such as multiple myeloma and Huntington's disease. These reporters, usually consisting of a recognition sequence fused to an analytical handle, are designed to specifically evaluate enzymatic activity of certain members of the UPS including the proteasome, E3 ubiquitin ligases, and deubiquitinating enzymes. This review highlights the more commonly used reporters employed in a variety of scenarios ranging from high-throughput screening of novel inhibitors to single cell microscopy techniques measuring E3 ligase or proteasome activity. Finally, a recent study is presented highlighting the development of a novel degron-based substrate designed to overcome the limitations of current reporting techniques in measuring E3 ligase and proteasome activity in patient samples.
Collapse
|
11
|
Sommi P, Necchi V, Vitali A, Montagna D, De Luigi A, Salmona M, Ricci V, Solcia E. PaCS is a novel cytoplasmic structure containing functional proteasome and inducible by cytokines/trophic factors. PLoS One 2013; 8:e82560. [PMID: 24358206 PMCID: PMC3866174 DOI: 10.1371/journal.pone.0082560] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/24/2013] [Indexed: 12/31/2022] Open
Abstract
A variety of ubiquitinated protein-containing cytoplasmic structures has been reported, from aggresomes to aggresome-like induced structures/sequestosomes or particle-rich cytoplasmic structures (PaCSs) that we recently observed in some human diseases. Nevertheless, the morphological and cytochemical patterns of the different structures remain largely unknown thus jeopardizing their univocal identification. Here, we show that PaCSs resulted from proteasome and polyubiquitinated protein accumulation into well-demarcated, membrane-free, cytoskeleton-poor areas enriched in glycogen and glycosaminoglycans. A major requirement for PaCS detection by either electron or confocal microscopy was the addition of osmium to aldehyde fixatives. However, by analyzing living cells, we found that proteasome chymotrypsin-like activity concentrated in well-defined cytoplasmic structures identified as PaCSs by ultrastructural morphology and immunocytochemistry of the same cells. PaCSs differed ultrastructurally and cytochemically from sequestosomes which may coexist with PaCSs. In human dendritic or natural killer cells, PaCSs were induced in vitro by cytokines/trophic factors during differentiation/activation from blood progenitors. Our results provide evidence that PaCS is indeed a novel distinctive cytoplasmic structure which may play a critical role in the ubiquitin–proteasome system response to immune, infectious or proneoplastic stimuli.
Collapse
Affiliation(s)
- Patrizia Sommi
- Department of Molecular Medicine, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Pathologic Anatomy Service, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Vittorio Necchi
- Department of Molecular Medicine, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Centro Grandi Strumenti, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Agostina Vitali
- Department of Molecular Medicine, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Daniela Montagna
- Pediatric Hematology/Oncology Service, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Ada De Luigi
- IRCCS Istituto di Ricerche Farmacologiche “Mario Negri”, Milan, Italy
| | - Mario Salmona
- IRCCS Istituto di Ricerche Farmacologiche “Mario Negri”, Milan, Italy
| | - Vittorio Ricci
- Department of Molecular Medicine, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- * E-mail: (VR); (ES)
| | - Enrico Solcia
- Department of Molecular Medicine, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Pathologic Anatomy Service, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- * E-mail: (VR); (ES)
| |
Collapse
|
12
|
A comparative analysis of the ubiquitination kinetics of multiple degrons to identify an ideal targeting sequence for a proteasome reporter. PLoS One 2013; 8:e78082. [PMID: 24205101 PMCID: PMC3812159 DOI: 10.1371/journal.pone.0078082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 09/09/2013] [Indexed: 01/03/2023] Open
Abstract
The ubiquitin proteasome system (UPS) is the primary pathway responsible for the recognition and degradation of misfolded, damaged, or tightly regulated proteins. The conjugation of a polyubiquitin chain, or polyubiquitination, to a target protein requires an increasingly diverse cascade of enzymes culminating with the E3 ubiquitin ligases. Protein recognition by an E3 ligase occurs through a specific sequence of amino acids, termed a degradation sequence or degron. Recently, degrons have been incorporated into novel reporters to monitor proteasome activity; however only a limited few degrons have successfully been incorporated into such reporters. The goal of this work was to evaluate the ubiquitination kinetics of a small library of portable degrons that could eventually be incorporated into novel single cell reporters to assess proteasome activity. After an intensive literary search, eight degrons were identified from proteins recognized by a variety of E3 ubiquitin ligases and incorporated into a four component degron-based substrate to comparatively calculate ubiquitination kinetics. The mechanism of placement of multiple ubiquitins on the different degron-based substrates was assessed by comparing the data to computational models incorporating first order reaction kinetics using either multi-monoubiquitination or polyubiquitination of the degron-based substrates. A subset of three degrons was further characterized to determine the importance of the location and proximity of the ubiquitination site lysine with respect to the degron. Ultimately, this work identified three candidate portable degrons that exhibit a higher rate of ubiquitination compared to peptidase-dependent degradation, a desired trait for a proteasomal targeting motif.
Collapse
|
13
|
Affiliation(s)
- Yuqing Lin
- Department of Chemistry, University of Gothenburg, S-41296, Gothenburg, Sweden
| | | | | | | |
Collapse
|
14
|
Quaglio E, Restelli E, Garofoli A, Dossena S, De Luigi A, Tagliavacca L, Imperiale D, Migheli A, Salmona M, Sitia R, Forloni G, Chiesa R. Expression of mutant or cytosolic PrP in transgenic mice and cells is not associated with endoplasmic reticulum stress or proteasome dysfunction. PLoS One 2011; 6:e19339. [PMID: 21559407 PMCID: PMC3084828 DOI: 10.1371/journal.pone.0019339] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 03/27/2011] [Indexed: 12/20/2022] Open
Abstract
The cellular pathways activated by mutant prion protein (PrP) in genetic prion diseases, ultimately leading to neuronal dysfunction and degeneration, are not known. Several mutant PrPs misfold in the early secretory pathway and reside longer in the endoplasmic reticulum (ER) possibly stimulating ER stress-related pathogenic mechanisms. To investigate whether mutant PrP induced maladaptive responses, we checked key elements of the unfolded protein response (UPR) in transgenic mice, primary neurons and transfected cells expressing two different mutant PrPs. Because ER stress favors the formation of untranslocated PrP that might aggregate in the cytosol and impair proteasome function, we also measured the activity of the ubiquitin proteasome system (UPS). Molecular, biochemical and immunohistochemical analyses found no increase in the expression of UPR-regulated genes, such as Grp78/Bip, CHOP/GADD153, or ER stress-dependent splicing of the mRNA encoding the X-box-binding protein 1. No alterations in UPS activity were detected in mutant mouse brains and primary neurons using the UbG76V-GFP reporter and a new fluorogenic peptide for monitoring proteasomal proteolytic activity in vivo. Finally, there was no loss of proteasome function in neurons in which endogenous PrP was forced to accumulate in the cytosol by inhibiting cotranslational translocation. These results indicate that neither ER stress, nor perturbation of proteasome activity plays a major pathogenic role in prion diseases.
Collapse
Affiliation(s)
- Elena Quaglio
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Elena Restelli
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Anna Garofoli
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Sara Dossena
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Ada De Luigi
- Department of Biochemistry and Molecular Pharmacology, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Luigina Tagliavacca
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milan, Italy
| | - Daniele Imperiale
- Neurology Unit, Human Prion Diseases Center D.O.M.P., Maria Vittoria Hospital, Torino, Italy
| | - Antonio Migheli
- Neurology Unit, Human Prion Diseases Center D.O.M.P., Maria Vittoria Hospital, Torino, Italy
| | - Mario Salmona
- Department of Biochemistry and Molecular Pharmacology, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Roberto Sitia
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milan, Italy
| | - Gianluigi Forloni
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Milan, Italy
| | - Roberto Chiesa
- Dulbecco Telethon Institute, Milan, Italy
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Milan, Italy
- * E-mail:
| |
Collapse
|