Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Original Article
  • Published:

Phosphorylation by p38 MAP kinase is required for E2F1 degradation and keratinocyte differentiation

Abstract

The transcription factor E2F1 plays key roles in skin homeostasis, and is essential for normal keratinocyte proliferation and epidermal regeneration after injury. We have previously established that, in differentiating keratinocytes, E2F1 activity is controlled by nuclear export and subsequent degradation. These events are triggered by differentiation-induced stimulation of protein kinase C and p38 mitogen-activated protein kinase (MAPK). However, the mechanisms that induce E2F1 export from the nucleus and the role of p38 MAPK in this process are poorly understood. We now describe a novel regulatory pathway for E2F1, which involves phosphorylation by p38. We demonstrate that E2F1 forms complexes with active p38 through regions that exclude the N-terminus of this transcription factor, and that p38 activity is a major contributor to the phosphorylation status of E2F1 in keratinocytes. Using in vitro kinase assays, we identified Ser403 and Thr433 as the residues phosphorylated by p38. The biological significance of these observations is underscored by the inability of E2F1 mutants lacking one or both of these residues to be exported from the nucleus and degraded when keratinocytes receive differentiation stimuli, which results in impaired keratinocyte maturation.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6

Similar content being viewed by others

References

  • Apostolova MD, Ivanova IA, Dagnino C, D'Souza SJA, Dagnino L . (2002). Active import and export mechanisms regulate E2F-5 subcellular localization. J Biol Chem 277: 34471–34479.

    Article  CAS  Google Scholar 

  • Balasubramanian S, Ahmad N, Mukhtar H . (1999). Upregulation of E2F transcription factors in chemically induced mouse skin tumors. Int J Oncol 15: 387–390.

    CAS  PubMed  Google Scholar 

  • Berton TR, Mitchell DL, Guo R, Johnson DG . (2005). Regulation of epidermal apoptosis and DNA repair by E2F1 in response to ultraviolet B radiation. Oncogene 24: 2449–2460.

    Article  CAS  Google Scholar 

  • D'Souza SJA, Pajak A, Balazsi K, Dagnino L . (2001). Ca2+ and BMP-6 signalling regulate E2F during epidermal keratinocyte differentiation. J Biol Chem 276: 23531–23538.

    Article  CAS  Google Scholar 

  • D'Souza SJA, Vespa A, Murkherjee S, Maher A, Pajak S, Dagnino L . (2002). E2F-1 is essential for normal epidermal wound repair. J Biol Chem 277: 10626–10632.

    Article  CAS  Google Scholar 

  • Dagnino L, Fry CJ, Bartley SM, Farnham P, Gallie BL, Phillips RA . (1997). Expression patterns of the E2F family of transcription factors during murine epithelial development. Cell Growth Differ 8: 553–563.

    CAS  PubMed  Google Scholar 

  • Eckert RL, Crish JF, Efimova T, Dashti SR, Deucher A, Bone F et al. (2004). Regulation of involucrin gene expression. J Invest Dermatol 123: 13–22.

    Article  CAS  Google Scholar 

  • Fagan R, Flint KJ, Jones N . (1994). Phosphorylation of E2F-1 modulates its interaction with the retinoblastoma gene product and the adenoviral E4 19 kDa protein. Cell 78: 799–811.

    Article  CAS  Google Scholar 

  • Fuchs E . (1994). Epidermal differentiation and keratin gene expression. Princess Takamatsu Symp 24: 290–302.

    CAS  PubMed  Google Scholar 

  • Fuchs E . (2007). Scratching the surface of skin development. Nature 445: 834–842.

    Article  CAS  Google Scholar 

  • Fuchs E, Raghavan S . (2002). Getting under the skin of epidermal morphogenesis. Nat Rev Genet 3: 199–209.

    Article  CAS  Google Scholar 

  • Garcia-Alvarez G, Ventura V, Ros O, Gil J, Tauler A . (2007). Glycogen synthase kinase-3beta binds to E2F1 and regulates its transcriptional activity. Biochim Biophys Acta 1773: 375–382.

    Article  CAS  Google Scholar 

  • Ivanova IA, D'Souza SJA, Dagnino L . (2006). E2F stability is regulated by a novel-PKC/p38beta MAP kinase signalling pathway during keratinocyte differentiation. Oncogene 25: 430–437.

    Article  CAS  Google Scholar 

  • Ivanova IA, Dagnino L . (2007). Activation of p38- and CRM1-dependent nuclear export promotes E2F1 degradation during keratinocyte differentiation. Oncogene 26: 1147–1154.

    Article  CAS  Google Scholar 

  • Ivanova IA, Vespa A, Dagnino L . (2007). A novel mechanism of E2F1 regulation via nucleocytoplasmic shuttling: determinants of nuclear import and export. Cell Cycle 6: 2186–2195.

    Article  CAS  Google Scholar 

  • McClellan KA, Slack RS . (2007). Specific in vivo roles for E2Fs in differentiation and development. Cell Cycle 6: 2917–2927.

    Article  CAS  Google Scholar 

  • Pierce AM, Fisher SM, Conti CJ, Johnson DG . (1998). Deregulated expression of E2F1 induces hyperplasia and cooperates with ras in skin tumor development. Oncogene 16: 1267–1276.

    Article  CAS  Google Scholar 

  • Rampalli S, Li L, Mak E, Ge K, Brand M, Tapscott SJ et al. (2007). p38 MAPK signaling regulates recruitment of Ash2L-containing methyltransferase complexes to specific genes during differentiation. Nat Struct Mol Biol 14: 1150–1156.

    Article  CAS  Google Scholar 

  • Vaezi A, Bauer C, Vasioukhin V, Fuchs E . (2002). Actin cable dynamics and Rho/Rock orchestrate a polarized cytoskeletal architecture in the early steps of assembling a stratified epithelium. Dev Cell 3: 367–381.

    Article  CAS  Google Scholar 

  • Vandel L, Kouzarides T . (1999). Residues phosphorylated by TFIIH are required fpr E2F-1 degradation during S-phase. EMBO J 18: 4280–4291.

    Article  CAS  Google Scholar 

  • Vasioukhin V, Fuchs E . (2001). Actin dynamics and cell–cell adhesion in epithelia. Curr Opin Cell Biol 13: 76–84.

    Article  CAS  Google Scholar 

  • Zhang X, Gan L, Pan H, Guo S, He X, Olson ST et al. (2002). Phosphorylation of serine 256 suppresses transactivation by FKHR (FOXO1) by multiple mechanisms. Direct and indirect effects on nuclear/cytoplasmic shuttling and DNA binding. J Biol Chem 277: 45276–45284.

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank A Pajak for technical assistance. This work was supported by grants to LD from the Canadian Institutes of Health Research and from the Natural Sciences and Engineering Research Council of Canada (NSERC). During these studies, IAI held research studentships from the Terry Fox Foundation, through an award from National Cancer Institute of Canada, and from the Canadian Institutes of Health Research Training Program in Cancer Research and Technology Transfer.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to L Dagnino.

Additional information

Supplementary Information accompanies the paper on the Oncogene website (http://www.nature.com/onc)

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Cite this article

Ivanova, I., Nakrieko, KA. & Dagnino, L. Phosphorylation by p38 MAP kinase is required for E2F1 degradation and keratinocyte differentiation. Oncogene 28, 52–62 (2009). https://doi.org/10.1038/onc.2008.354

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/onc.2008.354

Keywords

This article is cited by

Search

Quick links