From transcription to transport: emerging roles for nuclear myosin I.
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.
Hofmann
Wilma A
WA
Department of Physiology and Biophysics, University of IL at Chicago, 835 S. Wolcott, Chicago, IL 60612, USA.
Johnson
Terezina
T
Klapczynski
Marcin
M
Fan
Ji-Lao
JL
de Lanerolle
Primal
P
D021581:Active Transport, Cell Nucleus; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D024461:Myosin Type I / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D011485:Protein Binding; D012318:RNA Polymerase I / Q000235:genetics; D012319:RNA Polymerase II / Q000235:genetics; D014157:Transcription Factors; D014158:Transcription, Genetic
D014157:Transcription Factors; D012319:RNA Polymerase II; D012318:RNA Polymerase I; D024461:Myosin Type I