Fig. 1.

Hsp27’s β4/β8 groove is a PPI hot spot for both client- and self-interactions. a Domain architecture of Hsp27 and Tau isoforms. b Left, HSQC spectra of ¹⁵N Hsp27 ACD alone (150 µM, red) or in the presence of 250 µM K18 (blue). Right, chemical shift perturbations in ACD upon binding of 250 µM K18 (top) or 0N4R (bottom). c Left, intensity ratios upon binding of Hsp27 IPV peptide, with unassigned residues shown in gray. Right, HSQC spectra of ¹⁵N Hsp27 ACD alone (150 µM, red) or in the presence of 250 µM Hsp27 IPV peptide (blue). d Isothermal calorimetry of Hsp27 ACD with IPV-derived peptides. Left, representative ITC curve for Hsp27 IPV H peptide. Right, table of affinity values. ND, no detectable binding. Values are represented as mean ± standard error of the mean (SEM) determined from a minimum of three independent experiments. Bold letters highlight the mutated residue