Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. Signal., 14 June 2011
Vol. 4, Issue 177, p. ra40
[DOI: 10.1126/scisignal.2001750]


Editor's Summary

Sensing G-Actin
Polymerization of monomeric actin (G-actin) into filamentous actin (F-actin) underlies changes in cell morphology and motility. The MRTF (myocardin-related transcription factor) group of transcriptional coactivators are actin-binding proteins. They are cytoplasmic in resting cells but accumulate in the nucleus when signal-induced F-actin assembly decreases G-actin concentration. Signals that lead to the formation of F-actin reduce the availability of G-actin and thus promote nuclear localization and activity of MRTF proteins. Mouilleron et al. determined the crystal structure of the actin-binding domain of MRTF-A, which consists of three actin-binding RPEL motifs with two intervening spacer sequences, in association with actin. All five actin binding sites are required to maintain the cytoplasmic localization of MRTF-A in unstimulated cells. These crystal structures reveal how increasing the concentration of monomeric actin—which leads to more molecules of actin binding to each molecule of MRTF-A—traps MRTF-A in the cytoplasm, preventing it from activating target genes. Thus, signal-dependent changes in actin’s polymerization status can be directly coupled to changes in gene expression.

Citation: S. Mouilleron, C. A. Langer, S. Guettler, N. Q. McDonald, R. Treisman, Structure of a Pentavalent G-Actin•MRTF-A Complex Reveals How G-Actin Controls Nucleocytoplasmic Shuttling of a Transcriptional Coactivator. Sci. Signal. 4, ra40 (2011).

Read the Full Text

Differences in the Nuclear Export Mechanism between Myocardin and Myocardin-related Transcription Factor A.
K. Hayashi and T. Morita (2013)
J. Biol. Chem. 288, 5743-5755
   Abstract »    Full Text »    PDF »
Actin-regulated feedback loop based on Phactr4, PP1 and cofilin maintains the actin monomer pool.
G. Huet, E. K. Rajakyla, T. Viita, K.-P. Skarp, M. Crivaro, J. Dopie, and M. K. Vartiainen (2013)
J. Cell Sci. 126, 497-507
   Abstract »    Full Text »    PDF »
G-actin regulates the shuttling and PP1 binding of the RPEL protein Phactr1 to control actomyosin assembly.
M. Wiezlak, J. Diring, J. Abella, S. Mouilleron, M. Way, N. Q. McDonald, and R. Treisman (2012)
J. Cell Sci. 125, 5860-5872
   Abstract »    Full Text »    PDF »
Myocardin-like protein 2 regulates TGF{beta} signaling in embryonic stem cells and the developing vasculature.
J. Li, N. Bowens, L. Cheng, X. Zhu, M. Chen, S. Hannenhalli, T. P. Cappola, and M. S. Parmacek (2012)
Development 139, 3531-3542
   Abstract »    Full Text »    PDF »
2011: Signaling Breakthroughs of the Year.
E. M. Adler (2012)
Science Signaling 5, eg1
   Abstract »    Full Text »    PDF »
Science Signaling Podcast: 14 June 2011.
R. Treisman, N. Q. McDonald, S. Mouilleron, and A. M. VanHook (2011)
Science Signaling 4, pc11
   Abstract »    Full Text »

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882