Structural basis of the P4B ATPase lipid flippase activity

Nat Commun. 2021 Oct 13;12(1):5963. doi: 10.1038/s41467-021-26273-0.

Abstract

P4 ATPases are lipid flippases that are phylogenetically grouped into P4A, P4B and P4C clades. The P4A ATPases are heterodimers composed of a catalytic α-subunit and accessory β-subunit, and the structures of several heterodimeric flippases have been reported. The S. cerevisiae Neo1 and its orthologs represent the P4B ATPases, which function as monomeric flippases without a β-subunit. It has been unclear whether monomeric flippases retain the architecture and transport mechanism of the dimeric flippases. Here we report the structure of a P4B ATPase, Neo1, in its E1-ATP, E2P-transition, and E2P states. The structure reveals a conserved architecture as well as highly similar functional intermediate states relative to dimeric flippases. Consistently, structure-guided mutagenesis of residues in the proposed substrate translocation path disrupted Neo1's ability to establish membrane asymmetry. These observations indicate that evolutionarily distant P4 ATPases use a structurally conserved mechanism for substrate transport.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry*
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Amino Acid Sequence
  • Binding Sites
  • Cell Membrane / chemistry
  • Cell Membrane / enzymology
  • Cloning, Molecular
  • Cryoelectron Microscopy
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Isoenzymes / chemistry
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Lysophospholipids / chemistry*
  • Lysophospholipids / metabolism
  • Membrane Transport Proteins / chemistry*
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Models, Molecular
  • Phosphatidylethanolamines / chemistry*
  • Phosphatidylethanolamines / metabolism
  • Phosphatidylserines / chemistry*
  • Phosphatidylserines / metabolism
  • Phospholipid Transfer Proteins / chemistry*
  • Phospholipid Transfer Proteins / genetics
  • Phospholipid Transfer Proteins / metabolism
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Substrate Specificity

Substances

  • Isoenzymes
  • Lysophospholipids
  • Membrane Transport Proteins
  • Phosphatidylethanolamines
  • Phosphatidylserines
  • Phospholipid Transfer Proteins
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • lysophosphatidylserine
  • phosphatidylethanolamine
  • Adenosine Triphosphatases
  • ATP9A protein, human
  • NEO1 protein, S cerevisiae