Opinion - Actin up in the nucleus

Scepticism regarding the existence of actin in the nucleus is finally giving way to the productive investigation of its functional roles. The identification of actin in several nuclear complexes implicates it in diverse nuclear activities including transcription, chromatin remodelling and nucleocytoplasmic trafficking. A major challenge is that actin does not seem to form large filamentous structures in the nucleus and might adopt unique conformations, the elucidation of which would greatly assist our understanding of its functions.