Identification of the domains responsible for the interaction between HSP90 and PABPN1.

<p><b>(A)</b> Representation of full-length HSP90 and the structural domains used to determine the PABPN1 binding domain. <b>(B)</b> Identification of HSP90 domains involved in the PABPN1 interaction. Lysates prepared from HEK293 cells transfected with GFP-tagged A17-PABPN1 and various Flag-tagged HSP90 domain constructs were subjected to IP with an anti-Flag antibody followed by anti-GFP immunoblotting. <b>(C)</b> Representation of PABPN1 and the structural domains used to determine the HSP90 binding domain. <b>(D)</b> Identification of PABPN1 domains involved in the HSP90 interaction. Bacterial GST-HSP90(233–439) fusion proteins, immobilized on glutathione-Sepharose 4B beads, were incubated with lysates from HEK293 cells expressing various HA-tagged PABPN1 domain constructs. The precipitated proteins were subjected to anti-HA immunoblotting. A representative result from three independent experiments is shown. Asterisks highlight the various GST fusion proteins as confirmed by the comparison with the migration of molecular weight marker. IP, immunoprecipitation; PD, pull-down; NB, non-specific band.