The OBSL1 gene encodes a cytoskeletal adaptor protein, which is a member of the obscurin family. These proteins help linking the internal cytoskeleton of the cell with its cellular membrane. The OBSL1 protein has numerous (Ig)-like domains at both termini, while in the middle there is a fibronectin type 3 domain. This protein has 3 isoforms as a consequence of alternative splicing. Two of these variants named OBSL1-A and OBSL1-B are highly expressed in cardiac tissue.