Cytoskeletal Linker Proteins - Plakins

Plakins are a family of large multidomain proteins that crosslink the different types of cytoskeletal filaments and connect them to the cell junctions on the plasma membrane.

Plakins are usually dimeric, where each protein domain has a distinct role. The characteristic plakin domain, which directs the attachment to the target region, is followed by a coiled-coil rod domain that helps in dimerization or oligomerization.

These domains associate with plakin repeats, linker subdomains, and glycine-serine-arginine domains in different combinations to construct distinct proteins with varied functions.

For example, desmoplakins found in desmosomes contain plakin repeats followed by a glycine-serine-arginine domain.

 Plectin, another versatile cytoskeletal linker, comprises distinct and overlapping domains for binding each of the three types of cytoskeletal filaments, and membrane proteins like integrins.