Cytoskeleton-associated proteins (CAPs) are involved in the organization of microtubules and transportation of vesicles and organelles along the cytoskeletal network. A conserved motif, CAP-Gly, has been identified in a number of CAPs, including CLIP-170 and dynactins. The crystal structure of Caenorhabditis elegans F53F4.3 protein CAP-Gly domain was recently solved. The domain contains three beta-strands. The most conserved sequence, GKNDG, is located in two consecutive sharp turns on the surface, forming the entrance to a groove.