2. Academic Validation
  3. Mitochondrial amidoxime-reducing component 1 p.Ala165Thr increases protein degradation mediated by the proteasome

Mitochondrial amidoxime-reducing component 1 p.Ala165Thr increases protein degradation mediated by the proteasome

  • Liver Int. 2024 Feb 20. doi: 10.1111/liv.15857.
Tanmoy Dutta 1,  Kavitha Sasidharan 1,  Ester Ciociola 1,  Grazia Pennisi 1 2,  Francesca R Noto 1 3,  Lohitesh Kovooru 1,  Tobias Kroon 4,  Anna Lindblom 4,  Yue Du 5,  Mohammad Pirmoradian 6,  Simonetta Wallin 4,  Rosellina M Mancina 1,  Daniel Lindén 4 7,  Stefano Romeo 1 3 8
Affiliations

Affiliations

  • 1 Department of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy, Wallenberg Laboratory, University of Gothenburg, Gothenburg, Sweden.
  • 2 Section of Gastroenterology and Hepatology, Dipartimento Di Promozione Della Salute, Materno Infantile, Medicina Interna e Specialistica Di Eccellenza (PROMISE), University of Palermo, Palermo, Italy.
  • 3 Department of Medical and Surgical Sciences, University Magna Graecia, Catanzaro, Italy.
  • 4 Bioscience Metabolism, Research and Early Development Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
  • 5 Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom.
  • 6 Translational Science and Experimental Medicine, Research and Early Development Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
  • 7 Division of Endocrinology, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
  • 8 Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden.
PMID: 38375985 DOI: 10.1111/liv.15857
Abstract

Objective: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global health concern with no effective and specific drug treatment available. The rs2642438 minor allele in mitochondrial amidoxime-reducing component 1 (MARC1) results in an aminoacidic substitution (p.Ala165Thr) and associates with protection against MASLD. However, the mechanisms behind this protective effect are unknown. In this study, we examined the consequences of this aminoacidic substitution on protein stability and subcellular localization.

Methods: We overexpressed the human MARC1 A165 (wild-type) or 165T (mutant) in vivo in mice and in vitro in human hepatoma cells (HepG2 and HuH-7), generated several mutants at position 165 by in situ mutagenesis and then examined protein levels. We also generated HepG2 cells stably overexpressing MARC1 A165 or 165T to test the effect of this substitution on MARC1 subcellular localization.

Results: MARC1 165T overexpression resulted in lower protein levels than A165 both in vivo and in vitro. Similarly, any mutant at position 165 showed lower protein levels compared to the wild-type protein. We showed that the 165T mutant protein is polyubiquitinated and its degradation is accelerated through lysine-48 ubiquitin-mediated proteasomal degradation. We also showed that the 165T substitution does not affect the MARC1 subcellular localization.

Conclusions: This study shows that alanine at position 165 in MARC1 is crucial for protein stability, and the threonine substitution at this position leads to a hypomorphic protein variant due to lower protein levels. Our result supports the notion that lowering hepatic MARC1 protein level may be a successful therapeutic strategy for treating MASLD.

Keywords

MASH; MASLD; MOSC domain-containing protein 1; MTARC1; NAFLD; NASH; fatty liver; molybdenum cofactor (MOCO) sulfurase C-terminal domain-containing protein 1 (MOSC1).

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