MAP kinase-activated protein kinase 2 (MAPKAP-K2, MK2; Gene ID: 9261) is a 400 AA (46kDa) large enzyme that plays a central role mainly in the inflammatory response and cytokines production. It belongs to the serine/threonine-protein kinase family and is also involved in endocytosis, reorganization of the cytoskeleton, cell migration, cell cycle control, chromatin remodeling, DNA damage response and transcriptional regulation.1-4
Following stress, it is phosphorylated (at Thr-222, Ser-272 and Thr-334) and activated by MAP kinase p38-alpha/MAPK14, leading to phosphorylation of substrates.5 Phosphorylation of Thr-334 (located between the kinase domain and the C-terminal regulatory domain) may serve as a switch for MK2 nuclear import and export. Phosphorylated MK2 masks the nuclear localization signal at its C-terminus by binding to p38. It unmasks the nuclear export signal, which is part of the second C-terminal helix packed along the surface of kinase domain C-lobe, and thereby carries p38 to the cytoplasm.6, 7
The heterodimer of MK2 with p38-alpha/MAPK14 forms a stable complex: molecules are positioned 'face to face' so that the ATP-binding sites of both kinases are at the heterodimer interface.8, 9 Other important interaction partners of MK2 have been identified, such as AKT110, HSP27/HspB111, 12, HSF113, PHC2 and SHC114.
Besides phosphorylation another important regulatory post-translational modification of MK2 is described: Sumoylation, which inhibits the protein kinase activity.15
Recently the inhibition of MK2/3 has been identified as an emerging strategy to manipulate the inflammatory response as a therapeutic option.16-18 Small-molecule pharmaceutical inhibitors SB-203580 or genistein block the activation of MK2.19, 20
All these data, together with the growing number of publication on the complex network organization (http://gopubmed.org/web/gopubmed/) underline the importance of MK2 in biomedical research.21
To enable researches to answer the many open questions regarding MAPK-activated protein kinase 2 faster and easier we have now developed our highly reliable MK2-Trap. MK2-Trap (just like our widely used GFP-Trap®) is based on our high quality alpaca antibody fragments (VHH, sdAb, nanobody) coupled to agarose beads. It facilitates the biochemical analysis of MK2 and its interacting partners. Specifically pull down human, murine or hamster MK2 from any biological sample (e.g. cell extracts or tissue material) irrespective of the phosphorylation status or other modifications. Efficiently perform subsequent analysis like Western Blot, Mass spectroscopy or enzyme activity measurements.
As our collaboration partner Prof. Dr. Matthias Gaestel (Head of Institute of Physiological Chemistry, Hannover Medical University, Germany) stated: “The MK2-Trap beads are great for pull-down from lysate; nearly full depletion of MK2 from the supernatant and also nice Co-IP of p38! Thus the beads will be well suited to purify sufficient material of endogenous MK2 for biochemical analysis.“
In a next step we will soon also introduce our MK2-Chromobody® for the intracellular live-cell analysis of endogenous MK2. Just write me an email or leave a comment below if you are interested in this exciting new research tool and want to learn more!
1. Clifton, A.D.; Young, P.R.; Cohen, P. A comparison of the substrate specificity of MAPKAP kinase-2 and MAPKAP kinase-3 and their activation by cytokines and cellular stress. FEBS Lett. 1996, 392, 209-214.
2. Kobayashi, M.; Nishita, M.; Mishima, T., et al. MAPKAPK-2-mediated LIM-kinase activation is critical for VEGF-induced actin remodeling and cell migration. The EMBO journal. 2006, 25, 713-726.
3. Manke, I.A.; Nguyen, A.; Lim, D., et al. MAPKAP kinase-2 is a cell cycle checkpoint kinase that regulates the G2/M transition and S phase progression in response to UV irradiation. Molecular cell. 2005, 17, 37-48.
4. Kopper, F.; Bierwirth, C.; Schon, M., et al. Damage-induced DNA replication stalling relies on MAPK-activated protein kinase 2 activity. Proceedings of the National Academy of Sciences of the United States of America. 2013, 110, 16856-16861.
5. Ben-Levy, R.; Leighton, I.A.; Doza, Y.N., et al. Identification of novel phosphorylation sites required for activation of MAPKAP kinase-2. The EMBO journal. 1995, 14, 5920-5930.
6. Meng, W.; Swenson, L.L.; Fitzgibbon, M.J., et al. Structure of mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 suggests a bifunctional switch that couples kinase activation with nuclear export. J Biol Chem. 2002, 277, 37401-37405.
7. Reinhardt, H.C.; Hasskamp, P.; Schmedding, I., et al. DNA damage activates a spatially distinct late cytoplasmic cell-cycle checkpoint network controlled by MK2-mediated RNA stabilization. Molecular cell. 2010, 40, 34-49.
8. ter Haar, E.; Prabhakar, P.; Liu, X., et al. Crystal structure of the p38 alpha-MAPKAP kinase 2 heterodimer. J Biol Chem. 2007, 282, 9733-9739.
9. White, A.; Pargellis, C.A.; Studts, J.M., et al. Molecular basis of MAPK-activated protein kinase 2:p38 assembly. Proceedings of the National Academy of Sciences of the United States of America. 2007, 104, 6353-6358.
10. Rane, M.J.; Coxon, P.Y.; Powell, D.W., et al. p38 Kinase-dependent MAPKAPK-2 activation functions as 3-phosphoinositide-dependent kinase-2 for Akt in human neutrophils. J Biol Chem. 2001, 276, 3517-3523.
11. Stokoe, D.; Engel, K.; Campbell, D.G., et al. Identification of MAPKAP kinase 2 as a major enzyme responsible for the phosphorylation of the small mammalian heat shock proteins. FEBS Lett. 1992, 313, 307-313.
12. Lavoie, J.N.; Lambert, H.; Hickey, E., et al. Modulation of cellular thermoresistance and actin filament stability accompanies phosphorylation-induced changes in the oligomeric structure of heat shock protein 27. Molecular and cellular biology. 1995, 15, 505-516.
13. Wang, X.; Khaleque, M.A.; Zhao, M.J., et al. Phosphorylation of HSF1 by MAPK-activated protein kinase 2 on serine 121, inhibits transcriptional activity and promotes HSP90 binding. J Biol Chem. 2006, 281, 782-791.
14. Yannoni, Y.M.; Gaestel, M.; Lin, L.L. P66(ShcA) interacts with MAPKAP kinase 2 and regulates its activity. FEBS Lett. 2004, 564, 205-211.
15. Chang, E.; Heo, K.S.; Woo, C.H., et al. MK2 SUMOylation regulates actin filament remodeling and subsequent migration in endothelial cells by inhibiting MK2 kinase and HSP27 phosphorylation. Blood. 2011, 117, 2527-2537.
16. Ronkina, N.; Kotlyarov, A.; Gaestel, M. MK2 and MK3--a pair of isoenzymes? Frontiers in bioscience : a journal and virtual library. 2008, 13, 5511-5521.
17. Gaestel, M. What goes up must come down: molecular basis of MAPKAP kinase 2/3-dependent regulation of the inflammatory response and its inhibition. Biological chemistry. 2013, 394, 1301-1315.
18. Gaestel, M.; Kotlyarov, A.; Kracht, M. Targeting innate immunity protein kinase signalling in inflammation. Nature reviews. Drug discovery. 2009, 8, 480-499.
19. Maulik, N.; Yoshida, T.; Zu, Y.L., et al. Ischemic preconditioning triggers tyrosine kinase signaling: a potential role for MAPKAP kinase 2. The American journal of physiology. 1998, 275, H1857-1864.
20. Liao, Q.C.; Xiao, Z.S.; Qin, Y.F., et al. Genistein stimulates osteoblastic differentiation via p38 MAPK-Cbfa1 pathway in bone marrow culture. Acta pharmacologica Sinica. 2007, 28, 1597-1602.
21. Gaestel, M. MAPKAP kinases - MKs - two's company, three's a crowd. Nature reviews. Molecular cell biology. 2006, 7, 120-130.
Posted by Kourosh on Tue, May 13, 2014