Multivalent Dynamic Colocalization of Avian Influenza Polymerase and Nucleoprotein by Intrinsically Disordered ANP32A Reveals the Molecular Basis of Human Adaptation

Aldo Camacho-Zarco (1) , Lefan Yu (1) , Tim Krischuns (2) , Selin Dedeoglu (1) , Damien Maurin (1) , Guillaume Bouvignies (3) , Thibaut Crépin (1) , Rob Ruigrok (1) , Stephan Cusack (4) , Nadia Naffakh (2) , Martin Blackledge (1)

1 IBS - UMR 5075 - Institut de biologie structurale
2 CNRS-UMR3569 - Biologie des ARN et virus influenza - RNA Biology of Influenza Virus
3 LBM UMR 7203 - Laboratoire des biomolécules
4 EMBL - European Molecular Biology Laboratory [Grenoble]

Adaptation of avian influenza RNA polymerase (FluPol) to human cells requires mutations on the 627-NLS domains of the PB2 subunit. The E627K adaptive mutation compensates a 33-amino-acid deletion in the acidic intrinsically disordered domain of the host transcription regulator ANP32A, a deletion that restricts FluPol activity in mammalian cells. The function of ANP32A in the replication transcription complex and in particular its role in host restriction remains poorly understood. Here we characterize ternary complexes formed between ANP32A, FluPol, and the viral nucleoprotein, NP, supporting the putative role of ANP32A in shuttling NP to the replicase complex. We demonstrate that while FluPol and NP can simultaneously bind distinct linear motifs on avian ANP32A, the deletion in the shorter human ANP32A blocks this mode of colocalization. NMR reveals that NP and human-adapted FluPol, containing the E627 K mutation, simultaneously bind the identical extended linear motif on human ANP32A in an electrostatically driven, highly dynamic and multivalent ternary complex. This study reveals a probable molecular mechanism underlying host adaptation, whereby E627K, which enhances the basic surface of the 627 domain, is selected to confer the necessary multivalent properties to allow ANP32A to colocalize NP and FluPol in human cells.

Domaines: Sciences du Vivant [q-bio]

Aldo Camacho-Zarco, Lefan Yu, Tim Krischuns, Selin Dedeoglu, Damien Maurin, et al.. Multivalent Dynamic Colocalization of Avian Influenza Polymerase and Nucleoprotein by Intrinsically Disordered ANP32A Reveals the Molecular Basis of Human Adaptation. Journal of the American Chemical Society, 2023, 145 (38), pp.20985-21001. ⟨10.1021/jacs.3c06965⟩. ⟨pasteur-04269631⟩