Abstract
To study the role of protein kinase B (PKB) in response to cellular stress, we examined PKBalpha activity following different stress treatments. Hyperosmotic but not chemical stress resulted in inactivation of PKBalpha and prevented activation by pervanadate and mitogens. Hyperosmotic shock did not affect the MAP kinase pathway, suggesting that this inhibitory effect was specific for PKB. Our data further indicate that downregulation occurs via dephosphorylation of Thr308 and Ser473, the major regulatory phosphorylation sites of PKBalpha. Indeed, calyculin A, which inhibits protein phosphatases 1 and 2A, effectively blocked hyperosmotic stress-mediated inactivation (dephosphorylation) of PKBalpha. High osmolarity did not affect phosphatidylinositol 3-kinase activity but led to a marked increase in PI(3,4,5)P3 and a decrease in PI(3,4)P2 formation after pervanadate stimulation, suggesting that hyperosmotic stress has an inhibitory effect on a phosphatidylinositol 5-phosphatase which converts PI(3,4,5)P3 into PI(3,4)P2. Immunofluorescence studies revealed that membrane translocation, a prerequisite for PKB activation, was not affected by hyperosmotic stress. Our results indicate that hyperosmotic stress can act at two levels: (i) inhibition of phosphorylation of Thr308 and Ser473 by upstream kinases and (ii) by promoting rapid dephosphorylation of these regulatory sites.
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- Ahmed N. N., Grimes H. L., Bellacosa A., Chan T. O., Tsichlis P. N. Transduction of interleukin-2 antiapoptotic and proliferative signals via Akt protein kinase. Proc Natl Acad Sci U S A. 1997 Apr 15;94(8):3627–3632. doi: 10.1073/pnas.94.8.3627. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Alessi D. R., Andjelkovic M., Caudwell B., Cron P., Morrice N., Cohen P., Hemmings B. A. Mechanism of activation of protein kinase B by insulin and IGF-1. EMBO J. 1996 Dec 2;15(23):6541–6551. [PMC free article] [PubMed] [Google Scholar]
- Alessi D. R., Gomez N., Moorhead G., Lewis T., Keyse S. M., Cohen P. Inactivation of p42 MAP kinase by protein phosphatase 2A and a protein tyrosine phosphatase, but not CL100, in various cell lines. Curr Biol. 1995 Mar 1;5(3):283–295. doi: 10.1016/s0960-9822(95)00059-5. [DOI] [PubMed] [Google Scholar]
- Alessi D. R., James S. R., Downes C. P., Holmes A. B., Gaffney P. R., Reese C. B., Cohen P. Characterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase Balpha. Curr Biol. 1997 Apr 1;7(4):261–269. doi: 10.1016/s0960-9822(06)00122-9. [DOI] [PubMed] [Google Scholar]
- Alessi D. R., Kozlowski M. T., Weng Q. P., Morrice N., Avruch J. 3-Phosphoinositide-dependent protein kinase 1 (PDK1) phosphorylates and activates the p70 S6 kinase in vivo and in vitro. Curr Biol. 1998 Jan 15;8(2):69–81. doi: 10.1016/s0960-9822(98)70037-5. [DOI] [PubMed] [Google Scholar]
- Anderson K. E., Coadwell J., Stephens L. R., Hawkins P. T. Translocation of PDK-1 to the plasma membrane is important in allowing PDK-1 to activate protein kinase B. Curr Biol. 1998 Jun 4;8(12):684–691. doi: 10.1016/s0960-9822(98)70274-x. [DOI] [PubMed] [Google Scholar]
- Andjelković M., Alessi D. R., Meier R., Fernandez A., Lamb N. J., Frech M., Cron P., Cohen P., Lucocq J. M., Hemmings B. A. Role of translocation in the activation and function of protein kinase B. J Biol Chem. 1997 Dec 12;272(50):31515–31524. doi: 10.1074/jbc.272.50.31515. [DOI] [PubMed] [Google Scholar]
- Andjelković M., Jakubowicz T., Cron P., Ming X. F., Han J. W., Hemmings B. A. Activation and phosphorylation of a pleckstrin homology domain containing protein kinase (RAC-PK/PKB) promoted by serum and protein phosphatase inhibitors. Proc Natl Acad Sci U S A. 1996 Jun 11;93(12):5699–5704. doi: 10.1073/pnas.93.12.5699. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bellacosa A., Testa J. R., Staal S. P., Tsichlis P. N. A retroviral oncogene, akt, encoding a serine-threonine kinase containing an SH2-like region. Science. 1991 Oct 11;254(5029):274–277. doi: 10.1126/science.254.5029.274. [DOI] [PubMed] [Google Scholar]
- Brunet A., Pouysségur J. Identification of MAP kinase domains by redirecting stress signals into growth factor responses. Science. 1996 Jun 14;272(5268):1652–1655. doi: 10.1126/science.272.5268.1652. [DOI] [PubMed] [Google Scholar]
- Burgering B. M., Coffer P. J. Protein kinase B (c-Akt) in phosphatidylinositol-3-OH kinase signal transduction. Nature. 1995 Aug 17;376(6541):599–602. doi: 10.1038/376599a0. [DOI] [PubMed] [Google Scholar]
- Chen C. A., Okayama H. Calcium phosphate-mediated gene transfer: a highly efficient transfection system for stably transforming cells with plasmid DNA. Biotechniques. 1988 Jul-Aug;6(7):632–638. [PubMed] [Google Scholar]
- Chou M. M., Blenis J. The 70 kDa S6 kinase complexes with and is activated by the Rho family G proteins Cdc42 and Rac1. Cell. 1996 May 17;85(4):573–583. doi: 10.1016/s0092-8674(00)81257-x. [DOI] [PubMed] [Google Scholar]
- Clarke N. G., Dawson R. M. Alkaline O leads to N-transacylation. A new method for the quantitative deacylation of phospholipids. Biochem J. 1981 Apr 1;195(1):301–306. doi: 10.1042/bj1950301. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cross D. A., Alessi D. R., Cohen P., Andjelkovich M., Hemmings B. A. Inhibition of glycogen synthase kinase-3 by insulin mediated by protein kinase B. Nature. 1995 Dec 21;378(6559):785–789. doi: 10.1038/378785a0. [DOI] [PubMed] [Google Scholar]
- Datta S. R., Dudek H., Tao X., Masters S., Fu H., Gotoh Y., Greenberg M. E. Akt phosphorylation of BAD couples survival signals to the cell-intrinsic death machinery. Cell. 1997 Oct 17;91(2):231–241. doi: 10.1016/s0092-8674(00)80405-5. [DOI] [PubMed] [Google Scholar]
- Didichenko S. A., Tilton B., Hemmings B. A., Ballmer-Hofer K., Thelen M. Constitutive activation of protein kinase B and phosphorylation of p47phox by a membrane-targeted phosphoinositide 3-kinase. Curr Biol. 1996 Oct 1;6(10):1271–1278. doi: 10.1016/s0960-9822(02)70713-6. [DOI] [PubMed] [Google Scholar]
- Dudek H., Datta S. R., Franke T. F., Birnbaum M. J., Yao R., Cooper G. M., Segal R. A., Kaplan D. R., Greenberg M. E. Regulation of neuronal survival by the serine-threonine protein kinase Akt. Science. 1997 Jan 31;275(5300):661–665. doi: 10.1126/science.275.5300.661. [DOI] [PubMed] [Google Scholar]
- Favre B., Zolnierowicz S., Turowski P., Hemmings B. A. The catalytic subunit of protein phosphatase 2A is carboxyl-methylated in vivo. J Biol Chem. 1994 Jun 10;269(23):16311–16317. [PubMed] [Google Scholar]
- Franke T. F., Kaplan D. R., Cantley L. C., Toker A. Direct regulation of the Akt proto-oncogene product by phosphatidylinositol-3,4-bisphosphate. Science. 1997 Jan 31;275(5300):665–668. doi: 10.1126/science.275.5300.665. [DOI] [PubMed] [Google Scholar]
- Franke T. F., Yang S. I., Chan T. O., Datta K., Kazlauskas A., Morrison D. K., Kaplan D. R., Tsichlis P. N. The protein kinase encoded by the Akt proto-oncogene is a target of the PDGF-activated phosphatidylinositol 3-kinase. Cell. 1995 Jun 2;81(5):727–736. doi: 10.1016/0092-8674(95)90534-0. [DOI] [PubMed] [Google Scholar]
- Frech M., Andjelkovic M., Ingley E., Reddy K. K., Falck J. R., Hemmings B. A. High affinity binding of inositol phosphates and phosphoinositides to the pleckstrin homology domain of RAC/protein kinase B and their influence on kinase activity. J Biol Chem. 1997 Mar 28;272(13):8474–8481. doi: 10.1074/jbc.272.13.8474. [DOI] [PubMed] [Google Scholar]
- Galcheva-Gargova Z., Dérijard B., Wu I. H., Davis R. J. An osmosensing signal transduction pathway in mammalian cells. Science. 1994 Aug 5;265(5173):806–808. doi: 10.1126/science.8047888. [DOI] [PubMed] [Google Scholar]
- Gingras A. C., Kennedy S. G., O'Leary M. A., Sonenberg N., Hay N. 4E-BP1, a repressor of mRNA translation, is phosphorylated and inactivated by the Akt(PKB) signaling pathway. Genes Dev. 1998 Feb 15;12(4):502–513. doi: 10.1101/gad.12.4.502. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Han J., Lee J. D., Bibbs L., Ulevitch R. J. A MAP kinase targeted by endotoxin and hyperosmolarity in mammalian cells. Science. 1994 Aug 5;265(5173):808–811. doi: 10.1126/science.7914033. [DOI] [PubMed] [Google Scholar]
- Hemmings B. A. PH domains--a universal membrane adapter. Science. 1997 Mar 28;275(5308):1899–1899. doi: 10.1126/science.275.5308.1899. [DOI] [PubMed] [Google Scholar]
- Hemmings B. A. PtdIns(3,4,5)P3 gets its message across. Science. 1997 Jul 25;277(5325):534–534. doi: 10.1126/science.277.5325.534. [DOI] [PubMed] [Google Scholar]
- Hengartner M. O. Apoptosis. Death cycle and Swiss army knives. Nature. 1998 Jan 29;391(6666):441–442. doi: 10.1038/35036. [DOI] [PubMed] [Google Scholar]
- Jones P. F., Jakubowicz T., Pitossi F. J., Maurer F., Hemmings B. A. Molecular cloning and identification of a serine/threonine protein kinase of the second-messenger subfamily. Proc Natl Acad Sci U S A. 1991 May 15;88(10):4171–4175. doi: 10.1073/pnas.88.10.4171. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kauffmann-Zeh A., Rodriguez-Viciana P., Ulrich E., Gilbert C., Coffer P., Downward J., Evan G. Suppression of c-Myc-induced apoptosis by Ras signalling through PI(3)K and PKB. Nature. 1997 Feb 6;385(6616):544–548. doi: 10.1038/385544a0. [DOI] [PubMed] [Google Scholar]
- Kavanaugh W. M., Pot D. A., Chin S. M., Deuter-Reinhard M., Jefferson A. B., Norris F. A., Masiarz F. R., Cousens L. S., Majerus P. W., Williams L. T. Multiple forms of an inositol polyphosphate 5-phosphatase form signaling complexes with Shc and Grb2. Curr Biol. 1996 Apr 1;6(4):438–445. doi: 10.1016/s0960-9822(02)00511-0. [DOI] [PubMed] [Google Scholar]
- Kennedy S. G., Wagner A. J., Conzen S. D., Jordán J., Bellacosa A., Tsichlis P. N., Hay N. The PI 3-kinase/Akt signaling pathway delivers an anti-apoptotic signal. Genes Dev. 1997 Mar 15;11(6):701–713. doi: 10.1101/gad.11.6.701. [DOI] [PubMed] [Google Scholar]
- Khwaja A., Rodriguez-Viciana P., Wennström S., Warne P. H., Downward J. Matrix adhesion and Ras transformation both activate a phosphoinositide 3-OH kinase and protein kinase B/Akt cellular survival pathway. EMBO J. 1997 May 15;16(10):2783–2793. doi: 10.1093/emboj/16.10.2783. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Klippel A., Kavanaugh W. M., Pot D., Williams L. T. A specific product of phosphatidylinositol 3-kinase directly activates the protein kinase Akt through its pleckstrin homology domain. Mol Cell Biol. 1997 Jan;17(1):338–344. doi: 10.1128/mcb.17.1.338. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kohn A. D., Summers S. A., Birnbaum M. J., Roth R. A. Expression of a constitutively active Akt Ser/Thr kinase in 3T3-L1 adipocytes stimulates glucose uptake and glucose transporter 4 translocation. J Biol Chem. 1996 Dec 6;271(49):31372–31378. doi: 10.1074/jbc.271.49.31372. [DOI] [PubMed] [Google Scholar]
- Konishi H., Matsuzaki H., Tanaka M., Ono Y., Tokunaga C., Kuroda S., Kikkawa U. Activation of RAC-protein kinase by heat shock and hyperosmolarity stress through a pathway independent of phosphatidylinositol 3-kinase. Proc Natl Acad Sci U S A. 1996 Jul 23;93(15):7639–7643. doi: 10.1073/pnas.93.15.7639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kulik G., Klippel A., Weber M. J. Antiapoptotic signalling by the insulin-like growth factor I receptor, phosphatidylinositol 3-kinase, and Akt. Mol Cell Biol. 1997 Mar;17(3):1595–1606. doi: 10.1128/mcb.17.3.1595. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kyriakis J. M., Banerjee P., Nikolakaki E., Dai T., Rubie E. A., Ahmad M. F., Avruch J., Woodgett J. R. The stress-activated protein kinase subfamily of c-Jun kinases. Nature. 1994 May 12;369(6476):156–160. doi: 10.1038/369156a0. [DOI] [PubMed] [Google Scholar]
- Meier R., Alessi D. R., Cron P., Andjelković M., Hemmings B. A. Mitogenic activation, phosphorylation, and nuclear translocation of protein kinase Bbeta. J Biol Chem. 1997 Nov 28;272(48):30491–30497. doi: 10.1074/jbc.272.48.30491. [DOI] [PubMed] [Google Scholar]
- Meier R., Rouse J., Cuenda A., Nebreda A. R., Cohen P. Cellular stresses and cytokines activate multiple mitogen-activated-protein kinase kinase homologues in PC12 and KB cells. Eur J Biochem. 1996 Mar 15;236(3):796–805. doi: 10.1111/j.1432-1033.1996.00796.x. [DOI] [PubMed] [Google Scholar]
- Pullen N., Dennis P. B., Andjelkovic M., Dufner A., Kozma S. C., Hemmings B. A., Thomas G. Phosphorylation and activation of p70s6k by PDK1. Science. 1998 Jan 30;279(5351):707–710. doi: 10.1126/science.279.5351.707. [DOI] [PubMed] [Google Scholar]
- Seed B., Aruffo A. Molecular cloning of the CD2 antigen, the T-cell erythrocyte receptor, by a rapid immunoselection procedure. Proc Natl Acad Sci U S A. 1987 May;84(10):3365–3369. doi: 10.1073/pnas.84.10.3365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Srinivasan M., Begum N. Regulation of protein phosphatase 1 and 2A activities by insulin during myogenesis in rat skeletal muscle cells in culture. J Biol Chem. 1994 Apr 29;269(17):12514–12520. [PubMed] [Google Scholar]
- Stokoe D., Stephens L. R., Copeland T., Gaffney P. R., Reese C. B., Painter G. F., Holmes A. B., McCormick F., Hawkins P. T. Dual role of phosphatidylinositol-3,4,5-trisphosphate in the activation of protein kinase B. Science. 1997 Jul 25;277(5325):567–570. doi: 10.1126/science.277.5325.567. [DOI] [PubMed] [Google Scholar]
- Verheij M., Bose R., Lin X. H., Yao B., Jarvis W. D., Grant S., Birrer M. J., Szabo E., Zon L. I., Kyriakis J. M. Requirement for ceramide-initiated SAPK/JNK signalling in stress-induced apoptosis. Nature. 1996 Mar 7;380(6569):75–79. doi: 10.1038/380075a0. [DOI] [PubMed] [Google Scholar]
- Walker K. S., Deak M., Paterson A., Hudson K., Cohen P., Alessi D. R. Activation of protein kinase B beta and gamma isoforms by insulin in vivo and by 3-phosphoinositide-dependent protein kinase-1 in vitro: comparison with protein kinase B alpha. Biochem J. 1998 Apr 1;331(Pt 1):299–308. doi: 10.1042/bj3310299. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Whitman M., Kaplan D. R., Schaffhausen B., Cantley L., Roberts T. M. Association of phosphatidylinositol kinase activity with polyoma middle-T competent for transformation. Nature. 1985 May 16;315(6016):239–242. doi: 10.1038/315239a0. [DOI] [PubMed] [Google Scholar]
- Woscholski R., Parker P. J. Inositol lipid 5-phosphatases--traffic signals and signal traffic. Trends Biochem Sci. 1997 Nov;22(11):427–431. doi: 10.1016/s0968-0004(97)01120-1. [DOI] [PubMed] [Google Scholar]
- del Peso L., González-García M., Page C., Herrera R., Nuñez G. Interleukin-3-induced phosphorylation of BAD through the protein kinase Akt. Science. 1997 Oct 24;278(5338):687–689. doi: 10.1126/science.278.5338.687. [DOI] [PubMed] [Google Scholar]