Binding of sHSPs to the elastic I-bands in failing human heart. (A and B) Representative immunofluorescence images of sectioned myocardial tissue from control donor hearts and failing hearts with DCM. (A) Immunostaining for endogenous HSP27 (secondary antibody: FITC-conjugated IgG; left) and counterstaining for PEVK titin (secondary antibody: Cy3-conjugated IgG; middle). (B) Immunostaining for endogenous αB-crystallin (secondary antibody: FITC-conjugated IgG; left) and counterstaining for PEVK titin (secondary antibody: Cy3-conjugated IgG; middle). Right panels show merged images. (insets) Higher-power images from sections differing from those shown in the respective main panels. Bars, 5 µm. (C) Relative I-band positions of endogenous sHSP and PEVK at different SLs in DCM cardiomyocytes (left). Each data point represents an epitope–epitope (E-E) distance value measured across the Z-disk. Regression curves are of order 2. The right panel illustrates the range of sHSP binding locations on titin.