Structure and functional interactions of INO80 actin/Arp module.
The presence and functions of nuclear actin have been controversial due to the lack of molecular mechanisms. Nuclear actin and actin-related proteins (Arps) are subunits of several chromatin remodelers, including the evolutionarily conserved INO80 chromatin-remodeling complex. Here, we present an improved cryo-EM structure of the yeast INO80 complex and the ... first 3D reconstruction of the INO80 actin/Arp module. The modular and subunit architecture is defined using a combination of subunit deletion analysis and published crosslinking-mass spectrometry. The functional interactions of the INO80 actin/Arp module with a nucleosome is 3D EM reconstructed in two different binding states. Nucleosomes initially bind to the Arp8 subunit and the substantial conformational changes maximize nucleosome contacts of the actin/Arp module, which could promote the bound nucleosome to be engaged onto the INO80 ATPase domain. Our findings suggest that the conserved nuclear actin/Arp module acts a conformational switch of the INO80 for nucleosome binding.
Mesh Terms:
Cryoelectron Microscopy, Image Processing, Computer-Assisted, Microfilament Proteins, Molecular Dynamics Simulation, Mutation, Nucleosomes, Protein Binding, Protein Domains, Protein Structure, Quaternary, Protein Subunits, Recombinant Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
Cryoelectron Microscopy, Image Processing, Computer-Assisted, Microfilament Proteins, Molecular Dynamics Simulation, Mutation, Nucleosomes, Protein Binding, Protein Domains, Protein Structure, Quaternary, Protein Subunits, Recombinant Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
J Mol Cell Biol
Date: Dec. 01, 2018
PubMed ID: 30388237
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