1
|
Connelly EM, Rintala-Dempsey AC, Gundogdu M, Freeman EA, Koszela J, Aguirre JD, Zhu G, Kämäräinen O, Tadayon R, Walden H, Shaw GS. Capturing the catalytic intermediates of parkin ubiquitination. Proc Natl Acad Sci U S A 2024; 121:e2403114121. [PMID: 39078678 PMCID: PMC11317638 DOI: 10.1073/pnas.2403114121] [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: 02/13/2024] [Accepted: 06/24/2024] [Indexed: 07/31/2024] Open
Abstract
Parkin is an E3 ubiquitin ligase implicated in early-onset forms of Parkinson's disease. It catalyzes a transthiolation reaction by accepting ubiquitin (Ub) from an E2 conjugating enzyme, forming a short-lived thioester intermediate, and transfers Ub to mitochondrial membrane substrates to signal mitophagy. A major impediment to the development of Parkinsonism therapeutics is the lack of structural and mechanistic detail for the essential, short-lived transthiolation intermediate. It is not known how Ub is recognized by the catalytic Rcat domain in parkin that enables Ub transfer from an E2~Ub conjugate to the catalytic site and the structure of the transthiolation complex is undetermined. Here, we capture the catalytic intermediate for the Rcat domain of parkin in complex with ubiquitin (Rcat-Ub) and determine its structure using NMR-based chemical shift perturbation experiments. We show that a previously unidentified α-helical region near the Rcat domain is unmasked as a recognition motif for Ub and guides the C-terminus of Ub toward the parkin catalytic site. Further, we apply a combination of guided AlphaFold modeling, chemical cross-linking, and single turnover assays to establish and validate a model of full-length parkin in complex with UbcH7, its donor Ub, and phosphoubiquitin, trapped in the process of transthiolation. Identification of this catalytic intermediate and orientation of Ub with respect to the Rcat domain provides important structural insights into Ub transfer by this E3 ligase and explains how the previously enigmatic Parkinson's pathogenic mutation T415N alters parkin activity.
Collapse
Affiliation(s)
- Elizabeth M. Connelly
- Department of Biochemistry, The University of Western Ontario, London, ONN6A 5C1, Canada
| | | | - Mehmet Gundogdu
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, GlasgowG12 8QQ, UK
| | - E. Aisha Freeman
- Department of Biochemistry, The University of Western Ontario, London, ONN6A 5C1, Canada
| | - Joanna Koszela
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, GlasgowG12 8QQ, UK
| | - Jacob D. Aguirre
- Department of Biochemistry, The University of Western Ontario, London, ONN6A 5C1, Canada
| | - Grace Zhu
- Department of Biochemistry, The University of Western Ontario, London, ONN6A 5C1, Canada
| | - Outi Kämäräinen
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, GlasgowG12 8QQ, UK
| | - Roya Tadayon
- Department of Biochemistry, The University of Western Ontario, London, ONN6A 5C1, Canada
| | - Helen Walden
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, GlasgowG12 8QQ, UK
| | - Gary S. Shaw
- Department of Biochemistry, The University of Western Ontario, London, ONN6A 5C1, Canada
| |
Collapse
|
2
|
Oh SJ, Park K, Sonn SK, Oh GT, Lee MS. Pancreatic β-cell mitophagy as an adaptive response to metabolic stress and the underlying mechanism that involves lysosomal Ca 2+ release. Exp Mol Med 2023; 55:1922-1932. [PMID: 37653033 PMCID: PMC10545665 DOI: 10.1038/s12276-023-01055-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/18/2023] [Accepted: 05/11/2023] [Indexed: 09/02/2023] Open
Abstract
Mitophagy is an excellent example of selective autophagy that eliminates damaged or dysfunctional mitochondria, and it is crucial for the maintenance of mitochondrial integrity and function. The critical roles of autophagy in pancreatic β-cell structure and function have been clearly shown. Furthermore, morphological abnormalities and decreased function of mitochondria have been observed in autophagy-deficient β-cells, suggesting the importance of β-cell mitophagy. However, the role of authentic mitophagy in β-cell function has not been clearly demonstrated, as mice with pancreatic β-cell-specific disruption of Parkin, one of the most important players in mitophagy, did not exhibit apparent abnormalities in β-cell function or glucose homeostasis. Instead, the role of mitophagy in pancreatic β-cells has been investigated using β-cell-specific Tfeb-knockout mice (TfebΔβ-cell mice); Tfeb is a master regulator of lysosomal biogenesis or autophagy gene expression and participates in mitophagy. TfebΔβ-cell mice were unable to adaptively increase mitophagy or mitochondrial complex activity in response to high-fat diet (HFD)-induced metabolic stress. Consequently, TfebΔβ-cell mice exhibited impaired β-cell responses and further exacerbated metabolic deterioration after HFD feeding. TFEB was activated by mitochondrial or metabolic stress-induced lysosomal Ca2+ release, which led to calcineurin activation and mitophagy. After lysosomal Ca2+ release, depleted lysosomal Ca2+ stores were replenished by ER Ca2+ through ER→lysosomal Ca2+ refilling, which supplemented the low lysosomal Ca2+ capacity. The importance of mitophagy in β-cell function was also demonstrated in mice that developed β-cell dysfunction and glucose intolerance after treatment with a calcineurin inhibitor that hampered TFEB activation and mitophagy.
Collapse
Affiliation(s)
- Soo-Jin Oh
- Soonchunhyang Institute of Medi-bio Science and Division of Endocrinology, Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, 31151, Korea
| | - Kihyoun Park
- Soonchunhyang Institute of Medi-bio Science and Division of Endocrinology, Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, 31151, Korea
| | - Seong Keun Sonn
- Heart-Immune-Brain Network Research Center, Department of Life Science, Ewha Womans University, Seoul, 03767, Korea
| | - Goo Taeg Oh
- Heart-Immune-Brain Network Research Center, Department of Life Science, Ewha Womans University, Seoul, 03767, Korea
| | - Myung-Shik Lee
- Soonchunhyang Institute of Medi-bio Science and Division of Endocrinology, Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, 31151, Korea.
| |
Collapse
|
3
|
Connelly EM, Frankel KS, Shaw GS. Parkin and mitochondrial signalling. Cell Signal 2023; 106:110631. [PMID: 36803775 DOI: 10.1016/j.cellsig.2023.110631] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023]
Abstract
Aging, toxic chemicals and changes to the cellular environment are sources of oxidative damage to mitochondria which contribute to neurodegenerative conditions including Parkinson's disease. To counteract this, cells have developed signalling mechanisms to identify and remove select proteins and unhealthy mitochondria to maintain homeostasis. Two important proteins that work in concert to control mitochondrial damage are the protein kinase PINK1 and the E3 ligase parkin. In response to oxidative stress, PINK1 phosphorylates ubiquitin present on proteins at the mitochondrial surface. This signals the translocation of parkin, accelerates further phosphorylation, and stimulates ubiquitination of outer mitochondrial membrane proteins such as Miro1/2 and Mfn1/2. The ubiquitination of these proteins is the key step needed to target them for degradation via the 26S proteasomal machinery or eliminate the entire organelle through mitophagy. This review highlights the signalling mechanisms used by PINK1 and parkin and presents several outstanding questions yet to be resolved.
Collapse
Affiliation(s)
- Elizabeth M Connelly
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Karling S Frankel
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Gary S Shaw
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada.
| |
Collapse
|
4
|
Rappe A, McWilliams TG. Mitophagy in the aging nervous system. Front Cell Dev Biol 2022; 10:978142. [PMID: 36303604 PMCID: PMC9593040 DOI: 10.3389/fcell.2022.978142] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 09/07/2022] [Indexed: 02/01/2024] Open
Abstract
Aging is characterised by the progressive accumulation of cellular dysfunction, stress, and inflammation. A large body of evidence implicates mitochondrial dysfunction as a cause or consequence of age-related diseases including metabolic disorders, neuropathies, various forms of cancer and neurodegenerative diseases. Because neurons have high metabolic demands and cannot divide, they are especially vulnerable to mitochondrial dysfunction which promotes cell dysfunction and cytotoxicity. Mitophagy neutralises mitochondrial dysfunction, providing an adaptive quality control strategy that sustains metabolic homeostasis. Mitophagy has been extensively studied as an inducible stress response in cultured cells and short-lived model organisms. In contrast, our understanding of physiological mitophagy in mammalian aging remains extremely limited, particularly in the nervous system. The recent profiling of mitophagy reporter mice has revealed variegated vistas of steady-state mitochondrial destruction across different tissues. The discovery of patients with congenital autophagy deficiency provokes further intrigue into the mechanisms that underpin neural integrity. These dimensions have considerable implications for targeting mitophagy and other degradative pathways in age-related neurological disease.
Collapse
Affiliation(s)
- Anna Rappe
- Translational Stem Cell Biology and Metabolism Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Thomas G. McWilliams
- Translational Stem Cell Biology and Metabolism Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| |
Collapse
|