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:

The p85 regulatory subunit of PI3K mediates TSH–cAMP–PKA growth and survival signals

Abstract

Phosphatidylinositol 3-kinase (PI3K) is necessary for thyroid stimulating hormone (TSH)-induced cell cycle progression. To determine the molecular mechanism linking PI3K to TSH, we have identified a serine residue in p85αPI3K phosphorylated by protein kinase A (PKA) in vitro and in vivo. Expression of an alanine mutant (p85A) abolished cyclic AMP/TSH-induced cell cycle progression and was lethal in thyroid cells (FRTL-5). The aspartic version of the p85αPI3K (p85D) inhibited apoptosis following TSH withdrawal. The p85αPI3K wild type not the p85A bound PKA regulatory subunit RIIβ in cells stimulated with cAMP or TSH. The binding of the aspartic version of p85αPI3K to RIIβ was independent of cAMP or TSH stimulation. Similarly, binding of PI3K to p21Ras and activation of AKT, a downstream PI3K target, were severely impaired in cells expressing the p85A mutant. Finally, we found that the catalytic activity of PI3K was stimulated by TSH in cells expressing the wild-type p85αPI3K but not in cells expressing p85A. This latter mutant did not affect the epidermal growth factor-stimulated PI3K activity. We suggest that (1) TSH–cAMP-induced PKA phosphorylates p85αPI3K at serine 83, (2) phosphorylated p85αPI3K binds RIIβ-PKA and targets PKAII to the membrane, and (3) PI3K activity and p21Ras binding to PI3K increase and activate PI3K downstream targets. This pathway is essential for the transmission of TSH–cAMP growth signals.

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

  • Affaitati A, Cardone L, de Cristofaro T, Carlucci A, Ginsberg MD, Varrone S et al. (2003). Essential role of A-kinase anchor protein 121 for cAMP signaling to mitochondria. J Biol Chem 278: 4286–4294.

    Article  CAS  Google Scholar 

  • Al-Alawi N, Rose D, Buckmaster C, Ahn N, Rapp U, Meinkoth J et al. (1995). Thyrotropin-induced mitogenesis is Ras dependent but appears to bypass the Raf-dependent cytoplasmic kinase cascade. Mol Cell Biol 15: 1162–1168.

    Article  CAS  Google Scholar 

  • Ambesi-Impiombato FS, Parks LA, Coon HG . (1980). Culture of hormone-dependent functional epithelial cells from rat thyroids. Proc Natl Acad Sci USA 77: 3455–3459.

    Article  CAS  Google Scholar 

  • Chen J, Iyengar R . (1994). Suppression of Ras-induced transformation of NIH 3T3 cells by activated G alpha s. Science 263: 1278–1281.

    Article  CAS  Google Scholar 

  • Ciullo I, Diez-Roux G, Di Domenico M, Migliaccio A, Avvedimento VE . (2001). cAMP signaling selectively influences Ras effectors pathways. Oncogene 20: 1186–1192.

    Article  CAS  Google Scholar 

  • Cosentino C, Di Domenico M, Porcellini A, Cuozzo C, De Gregorio G, Santillo MR et al. (2006). p85 regulatory subunit of PI3K mediates cAMP-PKA and estrogens biological effects on growth and survival. Oncogene (in press).

  • Filippa N, Sable CL, Filloux C, Hemmings B, Van Obberghen E . (1999). Mechanism of protein kinase B activation by cyclic AMP-dependent protein kinase. Mol Cell Biol 19: 4989–5000.

    Article  CAS  Google Scholar 

  • Grieco D, Porcellini A, Avvedimento EV, Gottesman ME . (1996). Requirement for cAMP–PKA pathway activation by M phase-promoting factor in the transition from mitosis to interphase. Science 271: 1718–1723.

    Article  CAS  Google Scholar 

  • Kupperman E, Wen W, Meinkoth JL . (1993). Inhibition of thyrotropin-stimulated DNA synthesis by microinjection of inhibitors of cellular Ras and cyclic AMP-dependent protein kinase. Mol Cell Biol 13: 4477–4484.

    Article  CAS  Google Scholar 

  • Magnaldo I, Pouyssegur J, Paris S . (1989). Cyclic AMP inhibits mitogen-induced DNA synthesis in hamster fibroblasts, regardless of the signalling pathway involved. FEBS Lett 245: 65–69.

    Article  CAS  Google Scholar 

  • Maier U, Babich A, Nürnberg B . (1999). Roles of non-catalytic subunits in gbetagamma-induced activation of class I phosphoinositide 3-kinase isoforms beta and gamma. J Biol Chem 274: 29311–29317.

    Article  CAS  Google Scholar 

  • Miller MJ, Rioux L, Prendergast GV, Cannon S, White MA, Meinkoth JL . (1998). Differential effects of protein kinase A on Ras effector pathways. Mol Cell Biol 18: 3718–3726.

    Article  CAS  Google Scholar 

  • Porcellini A, Messina S, De Gregorio G, Feliciello A, Carlucci A, Barone M et al. (2003). The expression of the thyroid-stimulating hormone (TSH) receptor and the cAMP-dependent protein kinase RII beta regulatory subunit confers TSH–cAMP-dependent growth to mouse fibroblasts. J Biol Chem 278: 40621–40630.

    Article  CAS  Google Scholar 

  • Sable CL, Filippa N, Hemmings B, Van Obberghen E . (1997). cAMP stimulates protein kinase B in a Wortmannin-insensitive manner. FEBS Lett 409: 253–257.

    Article  CAS  Google Scholar 

  • Suh JM, Song JH, Kim DW, Kim H, Chung HK, Hwang JH et al. (2003). Regulation of the phosphatidylinositol 3-kinase, Akt/protein kinase B, FRAP/mammalian target of rapamycin, and ribosomal S6 kinase 1 signaling pathways by thyroid-stimulating hormone (TSH) and stimulating type TSH receptor antibodies in the thyroid gland. J Biol Chem 278: 21960–21971.

    Article  CAS  Google Scholar 

  • Wang X, Tang X, Li M, Marshall J, Mao Z . (2005). Regulation of neuroprotective activity of myocyte-enhancer factor 2 by cAMP–protein kinase A signaling pathway in neuronal survival. J Biol Chem 280: 16705–16713.

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We are indebted to Professor Angela Santoni for helpful suggestions and their continuous support. We are grateful to Professor Luisa Lenti at the Institute of Pathology of the University of Roma ‘La Sapienza’ for the help with the lipid kinase assay. This work was partly supported by MIUR (Italian Ministry of Education, University and Research). This paper is dedicated to the loving memory of Stelio Varrone.

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to E V Avvedimento or A Porcellini.

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

De Gregorio, G., Coppa, A., Cosentino, C. et al. The p85 regulatory subunit of PI3K mediates TSH–cAMP–PKA growth and survival signals. Oncogene 26, 2039–2047 (2007). https://doi.org/10.1038/sj.onc.1210011

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/sj.onc.1210011

Keywords

This article is cited by

Search

Quick links