Archvillin anchors in the Z-line of skeletal muscle via the nebulin C-terminus.

Z-Line of skeletal muscle is a complex protein network that likely plays an important role in signaling and muscle homeostasis. We used the yeast two-hybrid system to search for potential novel ligands of the Z-line portion of nebulin. We found that the C-terminal region of nebulin (residues 6457-6528) interacted with the C-terminus of archvillin (residues 1419-1687). Archvillin is a membrane skeletal protein that localizes to costameres, specialized adhesion sites in muscle. The binding sites between nebulin and archvillin were characterized using the yeast two-hybrid system, in vitro pull-down assays, and colocalization experiments in COS-7 cells. Our data suggest a model in which archvillin attaches directly to the Z-line through an interaction with the nebulin C-terminus. The interaction between nebulin and archvillin may provide a direct link between the sarcolemma and myofibrillar Z-lines.