CHCHD4 binding affects the active site of apoptosis inducing factor (AIF): Structural determinants for allosteric regulation

Structure. 2024 May 2;32(5):594-602.e4. doi: 10.1016/j.str.2024.02.008. Epub 2024 Mar 8.

Abstract

Apoptosis-inducing factor (AIF), which is confined to mitochondria of normal healthy cells, is the first identified caspase-independent cell death effector. Moreover, AIF is required for the optimal functioning of the respiratory chain machinery. Recent findings have revealed that AIF fulfills its pro-survival function by interacting with CHCHD4, a soluble mitochondrial protein which promotes the entrance and the oxidative folding of different proteins in the inner membrane space. Here, we report the crystal structure of the ternary complex involving the N-terminal 27-mer peptide of CHCHD4, NAD+, and AIF harboring its FAD (flavin adenine dinucleotide) prosthetic group in oxidized form. Combining this information with biophysical and biochemical data on the CHCHD4/AIF complex, we provide a detailed structural description of the interaction between the two proteins, validated by both chemical cross-linking mass spectrometry analysis and site-directed mutagenesis.

Keywords: SAXS; X-ray crystallography; flavoprotein; mass spectrometry; protein-protein interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Regulation
  • Apoptosis Inducing Factor* / chemistry
  • Apoptosis Inducing Factor* / genetics
  • Apoptosis Inducing Factor* / metabolism
  • Binding Sites
  • Catalytic Domain*
  • Crystallography, X-Ray
  • Humans
  • Mitochondrial Precursor Protein Import Complex Proteins*
  • Mitochondrial Proteins* / chemistry
  • Mitochondrial Proteins* / genetics
  • Mitochondrial Proteins* / metabolism
  • Models, Molecular*
  • NAD / chemistry
  • NAD / metabolism
  • Protein Binding*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism

Substances

  • Apoptosis Inducing Factor
  • Mitochondrial Proteins
  • CHCHD4 protein, human
  • NAD
  • AIFM1 protein, human
  • Transcription Factors
  • Mitochondrial Precursor Protein Import Complex Proteins