Figure 4.
ILK localizes to the sarcolemma and sarcomeric Z-discs of cardiomyocytes. (A) ILK is expressed in the endocardial (en) and myocardial (my) layer of the zebrafish heart. Cross-section through the cardiac ventricle of a wild-type zebrafish embryo at 72 hpf. (B,C) Coimmunostaining with an antibody directed against the sarcomeric Z-disc protein α-Actinin reveals colocalization of ILK and α-Actinin in zebrafish cardiomyocytes. (C) Merge of the anti-ILK and anti-α-Actinin stain. (D) As already observed in cardiomyocytes (C), ILK and α-Actinin also colocalize at sarcomeric Z-discs of zebrafish skeletal muscle cells. In addition, as indicated by arrowheads, sarcolemmal localization of ILK can be observed. (E–G) In the adult zebrafish (E) and rat (F,G) heart, ILK and α-Actinin also colocalize at sarcomeric Z-discs. (G) Immuno-gold staining and transmission electron microscopy of rat heart sections confirms localization of ILK at sarcomeric Z-discs. (H,I) msq mutant ILKL308P is expressed at normal levels in msq mutant zebrafish hearts (H) and skeletal muscle (I), and shows sarcolemmal staining (indicated by arrowheads) and co-localization with α-Actinin.