Download MendeleyActive conformations of neuronal Na + , K + -ATPase isoforms and a disease-causing mutant.
Christensen, M.E., Habeck, M., Katz, A., Fruergaard, M.U., Peleg, Y., Pick, U., Karlish, S.J.D., Nissen, P.(2026) Nat Commun 17
- PubMed: 42669691 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41467-026-75997-4
- Primary Citation Related Structures:
9RO9, 9ROA, 9ROD, 9ROE, 9ROF, 9ROG, 9ROH, 9ROI, 9ROJ, 9ROK, 9ROL, 9ROM, 9RON, 9ROO, 9ROP, 9ROQ - PubMed Abstract:
Na + ,K + -ATPases establish and maintain the vital electrochemical gradients for Na + and K + across animal cell membranes. The protein is a ternary complex composed of α, β and FXYD subunits, of which isoforms that fine-tune transport properties are expressed in a tissue-specific fashion. Here we report cryo-EM structures under active ATPase turn-over conditions of the ubiquitously expressed human α1β1FXYD1 and neuron-specific α3β1FXYD1 isoform complexes and probe their specific functional and biophysical properties. The data provides an extensive insight into Na + -transport of ATP-activated enzyme through four distinct conformational states, including a sodium-bound phosphoenzyme intermediate, denoted [Na 3 ]E2P. This conformation reveals a crucial structural change that precedes Na + release in the inward to outward (E1P-E2P) transition, within the general context of the sequential, active transport mechanism. We discuss the mechanism of the physiologically important differentiation in Na + affinity of α3 compared to α1, the co-operative Na + binding at the ion-binding sites, and the mechanistic aspects of cytoplasmic ion gating and extracellular Na + release. Finally we present the structures of a disease-causing mutant form of α3, associated with Alternating Hemiplegia of Childhood (Q140L). The mutation compromises a specific phospholipid-binding pocket and impedes polyunsaturated phospholipid-mediated stimulation of Na + ,K + -ATPase activity.
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Aarhus C, Denmark.
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