From transcription to transport: emerging roles for nuclear myosin IThis paper is one of a selection of papers published in this Special Issue, entitled 27th International West Coast Chromatin and Chromosome Conference, and has undergone the Journal's usual peer review process.

Abstract

Myosins are a superfamily of actin-activated ATPases that, in the cytoplasm, work together with actin as molecular motors. The presence of actin in the nucleus has been known for many years. The demonstration of a nuclear isoform of a myosin, nuclear myosin I (NMI), stimulated a great deal of interest in possible intranuclear motor functions of an acto-NMI complex. NMI has been shown to be involved in transcription by RNA polymerases I and II. In both cases, NMI interacts with the respective polymerase and is critically involved in the basic process of transcription. A recent study on intranuclear long-range chromosome movement has now demonstrated a role for NMI in the translocation of chromosome regions as well. Moreover, this movement is based on an active and directed process that is facilitated by an acto-NMI complex, establishing for the first time a functional role for a motor complex consisting of actin and a myosin in the nucleus.