Nuclear actin-binding proteins as modulators of gene transcription.
Dynamic transformations in the organization of the cellular microfilament system are the driving force behind fundamental biological processes such as cellular motility, cytokinesis, wound healing and secretion. Eukaryotic cells express a plethora of actin-binding proteins (ABPs) allowing cells to control the organization of the actin cytoskeleton in a flexible manner. These structural proteins were, not surprisingly, originally described as (major) constituents of the cytoplasm. However, in recent years, there has been a steady flow of reports detailing not only translocation of ABPs into and out of the nucleus but also describing their role in the nuclear compartment. This review focuses on recent developments pertaining to nucleocytoplasmic transport of ABPs, including their mode of translocation and nuclear function. In particular, evidence that structurally and functionally unrelated cytoplasmic ABPs regulate transcription activation by various nuclear (steroid hormone) receptors is steadily accruing. Furthermore, the recent finding that actin is a necessary component of the RNA polymerase II-containing preinitiation complex opens up new opportunities for nuclear ABPs in gene transcription regulation.
Gettemans
Jan
J
Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium. jan.gettemans@ugent.be
Van Impe
Katrien
K
Delanote
Veerle
V
Hubert
Thomas
T
Vandekerckhove
Joël
J
De Corte
Veerle
V
D000199:Actins / Q000378:metabolism; D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D021382:Protein Sorting Signals; D011987:Receptors, Steroid / Q000378:metabolism; D014158:Transcription, Genetic
D000199:Actins; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D021382:Protein Sorting Signals; D011987:Receptors, Steroid