Figure 5

Immunostains and traction force map of square cardiac myocytes. Actin (a, d and green in c, f) stained in a square myocyte was seen to be aligned along the diagonal, while sarcomeric α-actinin (b and red in c) marks the z-lines of the sarcomeres. Vinculin stains (e and red in f) show that this protein aggregates to corners of a square, with fibril-like structures appearing to emanate from the internal angle and radiating towards the center of the cell. The chromatin was stained with blue in c and f. Scale bar: 10 μm. The contractile traction measurement (i) shows that the contraction of myofibrils is centripetal with the highest traction concentrated at the corners, correlating with the distribution of the vinculin (g: DIC image; h: displacement field; i: contractile traction field). Adapted from Ref. [4].