Actin-related proteins involved in nuclear and chromatin dynamics

Actin plays central roles in the organization and dynamics of the cytoskeleton. Within a few decades of the first isolation of actin from muscle in 1941, it was shown that actin filaments form the main architecture of the cytoskeleton, and that the dynamics of the cytoskeleton are regulated by the assembly/disassembly of the filament, which depends on the adenosine diphosphate/triphosphate (ADP/ATP) exchange and on association with various actin-binding proteins. Because of these characteristics of actin, previous researchers hypothesized that actin and/or its evolutionarily related molecules were involved in the organization and dynamics of the nucleus. However, actin filaments were observed only in the cytoplasm, and no molecule evolutionarily related to actin was identified at the time. The hypothesis was therefore regarded with skepticism for a long time.