α-Actinin/titin interaction: A dynamic and mechanically stable cluster of bonds in the muscle Z-disk

Significance Muscle is the tissue in our body experiencing most extreme mechanical forces. The mechanism of active force generation has been investigated for more than 50 y and is fairly well understood. However, despite its physiological significance, it is still unknown what mechanical linkages hold together the muscle machinery under passive stretching forces. In this paper, we show with direct mechanical single-molecule measurements that an array of titin/α-actinin bonds composes a dynamic network that can provide stable anchoring, maintaining the integrity of the muscle Z-disk even under load. This dynamic network explains how components of the Z-disk are able to rapidly rearrange and, at the same time, form a long-term stable mechanical structure.