Figure 4.

Tau acts as a bona-fide Hsc70 client. (A) Active and inactive Hsc70 bind with the same specificity to tau. NMR intensity ratios I/I₀ (I, intensity of tau resonances in presence of active or inactive Hsc70; I₀, peak intensities of free tau) obtained from 2D ¹H–¹⁵N HSQC spectra of tau in the absence and presence of active Hsc70 (cyan) and inactive Hsc70 (blue). Molar ratios indicated. Superposition of absence (green) and presence of equimolar (black) and 2-fold excess (blue) ratios of inactive Hsc70 in highlighted resonances. (B) FP-LVEALY shows tau peptides VQIVYK (red), K18 tau (black) and model substrate NRLLTG (blue) compete for tracer binding in the SBD of Hsc70, whereas VQPVYK (gray) does not. Data are mean ± SD.