{Reference Type}: Journal Article
{Title}: Structural domain in the Titin N2B-us region binds to FHL2 in a force-activation dependent manner.
{Author}: Sun Y;Liu X;Huang W;Le S;Yan J;
{Journal}: Nat Commun
{Volume}: 15
{Issue}: 1
{Year}: 2024 May 27
{Factor}: 17.694
{DOI}: 10.1038/s41467-024-48828-7
{Abstract}: Titin N2B unique sequence (N2B-us) is a 572 amino acid sequence that acts as an elastic spring to regulate muscle passive elasticity. It is thought to lack stable tertiary structures and is a force-bearing region that is regulated by mechanical stretching. In this study, the conformation of N2B-us and its interaction with four-and-a-half LIM domain protein 2 (FHL2) are investigated using AlphaFold2 predictions and single-molecule experimental validation. Surprisingly, a stable alpha/beta structural domain is predicted and confirmed in N2B-us that can be mechanically unfolded at forces of a few piconewtons. Additionally, more than twenty FHL2 LIM domain binding sites are predicted to spread throughout N2B-us. Single-molecule manipulation experiments reveals the force-dependent binding of FHL2 to the N2B-us structural domain. These findings provide insights into the mechano-sensing functions of N2B-us and its interactions with FHL2.