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Arystarkhova E, Toustrup-Jensen MS, Holm R, Ko JK, Lee KE, Feschenko P, Ozelius LJ, Brashear A, Vilsen B, Sweadner KJ. Temperature instability of a mutation at a multidomain junction in Na,K-ATPase isoform ATP1A3 (p.Arg756His) produces a fever-induced neurological syndrome. J Biol Chem 2023; 299:102758. [PMID: 36462665 PMCID: PMC9860391 DOI: 10.1016/j.jbc.2022.102758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 12/02/2022] Open
Abstract
ATP1A3 encodes the α3 isoform of Na,K-ATPase. In the brain, it is expressed only in neurons. Human ATP1A3 mutations produce a wide spectrum of phenotypes, but particular syndromes are associated with unique substitutions. For arginine 756, at the junction of membrane and cytoplasmic domains, mutations produce encephalopathy during febrile infections. Here we tested the pathogenicity of p.Arg756His (R756H) in isogenic mammalian cells. R756H protein had sufficient transport activity to support cells when endogenous ATP1A1 was inhibited. It had half the turnover rate of wildtype, reduced affinity for Na+, and increased affinity for K+. There was modest endoplasmic reticulum retention during biosynthesis at 37 °C but little benefit from the folding drug phenylbutyrate (4-PBA), suggesting a tolerated level of misfolding. When cells were incubated at just 39 °C, however, α3 protein level dropped without loss of β subunit, paralleled by an increase of endogenous α1. Elevated temperature resulted in internalization of α3 from the surface along with some β subunit, accompanied by cytoplasmic redistribution of a marker of lysosomes and endosomes, lysosomal-associated membrane protein 1. After return to 37 °C, α3 protein levels recovered with cycloheximide-sensitive new protein synthesis. Heating in vitro showed activity loss at a rate 20- to 30-fold faster than wildtype, indicating a temperature-dependent destabilization of protein structure. Arg756 appears to confer thermal resistance as an anchor, forming hydrogen bonds among four linearly distant parts of the Na,K-ATPase structure. Taken together, our observations are consistent with fever-induced symptoms in patients.
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Affiliation(s)
- Elena Arystarkhova
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA.
| | | | - Rikke Holm
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Jae-Kyun Ko
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Kyung Eun Lee
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Polina Feschenko
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Laurie J Ozelius
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Allison Brashear
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York, USA
| | - Bente Vilsen
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Kathleen J Sweadner
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA.
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