Abstract
Members of the Bcl2 family of proteins are important regulators of programmed cell death pathways with individual members that can suppress (eg Bcl2, Bcl-XL) or promote (eg Bax, Bad) apoptosis. While the mechanism(s) of Bcl2’s anti-apoptotic function is not yet clear, introduction of Bcl2 into most eukaryotic cell types will protect the recipient cell from a wide variety of stress applications that lead to cell death. There are, however, physiologic situations in which Bcl2 expression apparently fails to protect cells from apoptosis (eg negative selection of thymocytes). Further, Bcl2 expression in patient tumor samples does not consistently correlate with a worse outcome or resistance to anticancer therapies. For example, patient response and survival following chemotherapy is independent of Bcl2 expression at least for pediatric patients with ALL. These findings indicate that simple expression of Bcl2 may not be enough to functionally protect cells from apoptosis. The finding that Bcl2 is post-translationally modified by phosphorylation suggests another level of regulation of function. Recent studies have shown that agonist-activated phosphorylation of Bcl2 at serine 70 (single site phosphorylation), a site within the flexible loop domain (FLD), is required for Bcl2’s full and potent anti-apoptotic function, at least in murine IL-3-dependent myeloid cell lines. Several protein kinases have now been demonstrated to be physiologic Bcl2 kinases indicating the importance of this post-translational modification. Since Bcl2 phosphorylation has been found to be a dynamic process involving both a Bcl2 kinase(s) and phosphatase(s), a mechanism exists to rapidly and reversibly regulate Bcl2’s activity and affect cell viability. In addition, multisite Bcl2 phosphorylation induced by anti-mitotic drugs like paclitaxel may inhibit Bcl2 indicating the potential wide range of functional consequences that this post-translational modification may have on function. While post-translational mechanisms other than phosphorylation may also regulate Bcl2’s function (eg ubiquitination), this review will focus on the regulatory role for phosphorylation and discuss its potential clinical ramifications.
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References
Korsmeyer SJ . Bcl2 initiates a new category of oncogenes: regulators of cell death Blood 1992 80: 879–886
Yang E, Korsmeyer SJ . Molecular thanatopsis: a discourse on the Bcl2 family and cell death Blood 1996 88: 386–401
Reed JC . Double identity for proteins of the Bcl2 family Nature 1997 387: 773–776
Adams JM, Cory S . The Bcl2 protein family: arbiters of cell survival Science 1998 281: 1322–1326
Reed JC . Bcl2 family proteins Oncogene 1998 17: 3225–3236
Tsujimoto Y, Finger L, Nowell PC, Croce CM . Cloning of the chromosome breakpoint of neoplastic B cells with the t(14,18) chromosome translocation Science 1984 226: 1097–1099
Bakhasi A, Jensen JP, Goldman P, Wright JJ, McBcride OW, Epstein AL, Korsmeyer SJ . Cloning the chromosomal breakpoint of t(14,18) human lymphomas: clustering around JH on chromosome 14 and near a transcriptional unit on 18 Cell 1985 41: 889–906
Cleary ML, Smith SD, Sklar J . Cloning and structural analysis of cDNAs for bcl2 and a hybrid bcl2/immunoglobulin transcript resulting from the t(14,18) translocation Cell 1986 47: 19–28
Vaux DL, Cory S, Adams JM . Bcl2 oncogene promotes haemopoietic cell survival and cooperates with c-myc to immortalize pre-B cells Nature 1988 335: 440–442
Hengartner MO, Ellis RE, Horvitz HR . Caenorhabditis elegans gene ced-9 protects cells from programmed cell death Nature 1992 356: 494–499
Vaux DL, Weissman IL, Kim SK . Prevention of programmed cell death in Caendorhabditis elegans by human bcl2 Science 1992 258: 1955–1957
Hengartner MO, Horvitz HR . C. elegans cell survival gene ced-9 encodes a functional homolog of the mammalian proto-oncogene bcl2 Cell 1994 76: 665–676
Rowan S, Fisher DE . Mechanisms of apoptotic cell death Leukemia 1997 11: 457–465
Wertz IE, Hanley MR . Diverse molecular provocation of programmed cell death Trends Biochem 1996 21: 359–365
Nunez G, London L, Hockenbery D, Alexander M, McKearn J, Korsmeyer SJ . Deregulated Bcl2 gene expression selectively prolongs survival of growth factor-deprived hematopoietic cell lines J Immunol 1990 144: 3602–3610
Batistatou A, Merry DE, Korsmeyer SJ, Green LA . Bcl2 affects survival but not neuronal differentiation of PC12 cells J Neurosci 1993 13: 4422–4428
May WS . Control of apoptosis by cytokines Adv Pharmacol 1997 41: 219–246
Sentman DL, Shutter JR, Hockenbery D, Kanagawa O, Korsmeyer SJ . Bcl2 inhibits multiple forms of apoptosis but not negative selection in thymocytes Cell 1991 67: 879–888
Strasser A, Harris AW, Cory S . Bcl2 transgene inhibits T cell death and perturbs thymic self-censorship Cell 1991 67: 889–899
Zhang J, Alter N, Reed JC, Borner C, Obeid LM, Hannun YA . Bcl2 interrupts the ceramide-mediated pathway of cell death Proc Natl Acad Sci USA 1996 93: 5325–5328
Miyashita T, Reed JC . Bcl2 oncoprotein blocks chemotherapy-induced apoptosis in a human leukemia cell line Blood 1993 81: 151–157
Yin DX, Schimke RT . Bcl2 expression delays drug-induced apoptosis but does not increase clonogenic survival after drug treatment in HeLa cells Cancer Res 1995 55: 4922–4928
Campos L, Rouault JP, Sabido O, Oriol P, Roubi N, Vasselon C, Archimbaud E, Magaud JP, Guyotat, D . High expression of Bcl2 protein in acute myeloid leukemia is associated with poor response to chemotherapy Blood 1993 81: 3091–3096
McDonell TJ, Troncosos P, Brisbay SM, Logothetis C, Ching LWK, Hsieh JT, Tu SM, Campbell ML . Expression of the proto-oncogene bcl2 in the prostate and its association with androgen-independent prostate cancer Cancer Res 1992 52: 6940–6944
Vaux DL, Aguila HL, Weissman IL . Bcl2 prevents death of factor deprived cells but fails to prevent apoptosis in targets of cell mediated killing Int Immunol 1992 4: 821–824
Uckun FM, Stewart CF, Reaman G, Chelstrom LM, Jin J, Chandan-Langlie M, Waddick KG, White J, Evans WE . In vitro and in vivo activity of topotecan against human B-lineage acute lymphoblastic leukemia cells Blood 1995 85: 2817–2818
Coustan-Smith E, Kitanaka A, Pui CH, McNinch L, Evans WE, Raimondi SC, Behm FG, Arico M, Campana D . Clinical relevance of Bcl2 overexpression in childhood acute lymphoblastic leukemia Blood 1996 87: 1140–1146
Ruvolo PP, Deng X, Carr BK, May WS . A functional role for mitochondrial PKC α in Bcl2 phosphorylation and suppression of apoptosis J Biol Chem 1998 273: 25436–25442
Pezzella F, Turley H, Kuzu I, Tungekar MF, Dunnill MS, Pierce CB, Harris A, Gatter KC, Mason DY . Bcl2 protein in non-small-cell lung carcinoma N Engl J Med 1993 329: 690–694
Joensuu H, Pylkkanen L, Toikkanen S . Bcl2 protein expression and long term survival in breast cancer Am J Path 1994 145: 1191–1198
Oltivai ZN, Milliman CL, Korsmeyer SJ . Bcl2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death Cell 1993 74: 609–619
Kornblau SM, Vu H, Ruvolo P, Estrov Z, O'Brien S, Cortes J, Kantarjian H, Andreeff M, May WS . Bax and PKC α modulate the prognostic impact of Bcl2 expression in acute myelogenous leukemia Clin Cancer Res 2000 6: 1401–1409
Salomons GS, Brady HJM, Verwijs-Janssen M, Van Den Berg JD, Hart AAM, Van Den Berg H, Behrendt H, Hahlen K, Smets LA . The Baxα:Bcl2 ratio modulates the response to dexamethasone in leukemic cells and is highly variable in childhood acute leukaemia Int J Cancer 1997 71: 959–965
May WS, Tyler PG, Ito T, Armstrong DK, Qatsha KA, Davidson NE . Interleukin-3 and bryostatin-1 mediate hyperphosphorylation of Bcl2a in association with suppression of apoptosis J Biol Chem 1994 269: 26865–26870
Ito T, Deng X, Carr BK, May WS . Bcl2 phosphorylation required for anti-apoptosis function J Biol Chem 1997 272: 11671–11673
Alnemeri ES, Robertson NM, Fernandes TF, Croce CM, Litwack G . Overexpressed full-length human Bcl2 extends the survival of bacuolovirus-infected SF9 insect cells Proc Natl Acad Sci USA 1992 89: 7295–7299
Hoffman R, Newlands S . Role of protein kinase C in adriamycin-induced erythroid differentiation of K562 cells Cancer Chemother Pharmacol 1991 28: 102–104
Carroll MP, May WS . Protein kinase C-mediated serine phosphorylation directly activates Raf-1 in murine hematopoietic cells J Biol Chem 1994 269: 1249–1256
Quick J, Ware JA, Driedger PE . The structure and biological function of the widely used inhibitor, H7, differs depending on commercial source Biochem Biophys Res Commun 1992 187: 657–663
Kennelly PJ, Krebs EG . Consensus sequences as substrate specificity determinants for protein kinases and protein phosphatases J Biol Chem 1991 266: 15555–15558
Haldar S, Jena N, Croce CM . Inactivation of Bcl2 by phosphorylation Proc Natl Acad Sci USA 1995 92: 4507–4511
Haldar S, Chintapalli J, Croce CM . Taxol-induced bcl2 phosphorylation and death of prostate cancer cells Cancer Res 1996 56: 1253–1255
Haldar S, Basu A, Croce CM . Serine-70 is one of the critical sites for drug-induced bcl2 phosphorylation in cancer cells Cancer Res 1998 58: 1609–1615
Yamamoto K, Ihijo H, Korsmeyer S . Bcl2 is phosphorylated and inactivated by an ASK1/Jun N-terminal protein kinase pathway normally activated at G2/M Mol Cell Biol 1999 19: 8469–8478
Blagosklonny MV, Schulte T, Nguyen P, Trepel J, Neckers LM . Taxol-induced apoptosis and phosphorylation of Bcl-2 protein involves c-Raf-1 and represents a novel c-Raf-1 signal transduction pathway Cancer Res 1996 56: 1851–1854
Blagosklonny MV, Giannakakou P, el-Deiry WS, Kingston DG, Higgs PI, Neckers L, Fojo T . Raf-1/bcl-2 phosphorylation: a step from microtubule damage to cell death Cancer Res 1997 57: 130–135
Blagosklonny MV, Chuman Y, Bergan RC, Fojo T . Mitogen-activated protein kinase pathway is dispensable for microtubule-active drug-induced Raf-1/Bcl-2 phosphorylation and apoptosis in leukemia cells Leukemia 1999 13: 1028–1036
Hu ZB, Minden MD, McCulloch EA . Phosphorylation of Bcl2 after exposure of human leukemic cells to retinoic acid Blood 1998 92: 1768–1775
Deng X, Ruvolo P, Carr B, May WS . Survival function of ERK1/2 as IL-3-activated staurosporine-resistant Bcl2 kinases Proc Natl Acad Sci USA 2000 97: 1578–1583
Srivasta RK, Mi QS, Hardwick M, Longo D . Deletion of the loop region of Bcl2 completely blocks paclitaxal-induced apoptosis Proc Natl Acad Sci USA 1999 96: 3775–3780
Tang C, Willingham MC, Reed JC, Miyashita T, Ray S, Ponnathpur V, Huang Y, Mahoney ME, Bullock G, Bhalla K . High levels of p26 Bcl2 oncoprotein retard taxol-induced apoptosis in human pre-B leukemia cells Leukemia 1994 8: 1960–1969
Wang S, Wang Z, Boise L, Dent P, Grant S . Loss of the Bcl2 phosphorylation loop domain increases resistance to human leukemic cells (U937) to paclitaxel-mediated mitochondrial dysfunction and apoptosis Biochem Biophys Res Com 1999 266: 15555–15558
Takayama S, Cazals-Hatem DL, Kitada S, Tanaka S et al. Evolutionary conservation of function among mammalian, avian, and viral homologs of the Bcl2 oncoprotein DNA Cell Biol 1994 13: 679–692
Chang BS, Minn AJ, Muchmore SW, Fesik SW, Thompson CB . Identification of a novel regulatory domain in Bcl-XL and Bcl2 EMBO J 1997 16: 968–977
Uhlmann EJ, D'Sa-Eipper C, Subramanian T, Wagner AJ, Hay N, Chinnadurai G . Deletion of a nonconserved region of Bcl2 confers a novel gain of function: suppression of apoptosis with concomitant cell proliferation Cancer Res 1996 56: 2506–2509
Petit PX, Susin S, Zamzami N, Mignoette B, Kroemer G . Mitochondria and programmed cell death: back to the future? FEBS Lett 1996 396: 7–13
Zhu W, Cowie A, Wasfy GW, Penn LZ, Leber B, Adams DW . Bcl2 mutants with restricted subcellular location reveaal spatially distinct pathways for apoptosis in different cell types EMBO J 1996 15: 4130–4140
Green DR, Reed JC . Mitochondria and apoptosis Science 1998 281: 1309–1312
Hunter JJ, Bond BL, Parslow TG . Functional dissection of the human Bcl2 protein: sequence requirements for inhibition of apoptosis Mol Cell Biol 1996 16: 877–883
Maundrell K, Antonsson B, Magnenat E, Camps M, Muda M, Chabert C, Gillieron C, Boschert U, Vial-Knecht E, Martinou JC, Arkinstall S . Bcl2 undergoes phosphorylation by c-Jun N-terminal/stress-activated protein kinase in the presence of constitutively active GTP binding protein Rac-1 J Biol Chem 1997 272: 25238–25242
Horiuchi M, Hayashida W, Kambe T, Yamada T, Dzau VJ . Angiotensin type 2 receptor dephosphorylates Bcl2 by activating mitogen-activated protein kinase phosphatase-1 and induces apoptosis J Biol Chem 1997 272: 19022–19029
Deng X, Ito T, Carr B, Mumby M, May WS . Reversible phosphorylation of Bcl2 following interleukin-3 or bryostatin-1 is mediated by direct interaction of protein phosphatase 2A J Biol Chem 1998 273: 34157–34163
Hannun YA . The sphingomyelin cycle and second messenger function of ceramide J Biol Chem 1994 269: 3125–3128
Jarvis WD, Grant S, Kolesnick RN . Ceramide and the induction of apoptosis Clin Cancer Res 1996 2: 1–6
Jarvis WD, Fornari FA, Auer KL, Freemerman AJ, Szabo E, Birrer MJ, Johnson CR, Barbour SE, Dent P, Grant S . Coordinate regulation of stress- and mitogen-activated protein kinases in apoptotic actions of ceramide and sphingosine Mol Pharm 1997 52: 935–947
Westwick JK, Bielawaska AE, Dbaibo G, Hannun YA, Brenner DA . Ceramide activates the stress-activated protein kinases J Biol Chem 1995 270: 22689–22692
Dobrowsky RT, Hannun YA . Ceramide stimulates a cytosolic protein phosphatase 2A J Biol Chem 1992 267: 5048–5051
Dobrowsky RT, Kamibayasha C, Mumby MC, Hannun YA . Ceramide activates a heterotrimeric protein phosphatase 2A J Biol Chem 1993 268: 15523–15530
Ruvolo PP, Deng X, Ito T, Carr BK, May WS . Ceramide induces Bcl2 dephosphorylation via a mechanism involving mitochondrial PP2A J Biol Chem 1999 274: 20296–20300
Nishizzuka Y . Intracellular signaling by hydrolysis of phospholipids and activation of protein kinase C Science 1992 258: 607–614
Luberto C, Hannun YA . Sphingomyelin synthetase, a potential regulator of intracellular levels of ceramide and diacylglycerol during SV40 transformation J Biol Chem 1998 273: 14550–14559
Rhee SG, Bae YS . Regulation of phosphoinositide-specific phospholipase C isozymes J Biol Chem 1997 272: 15045–15048
Dawson AP . Intracellular signaling: how do IP3 receptors work? Curr Biol 1997 7: 544–547
Newton AC . Protein kinase C: structure, function, and regulation J Biol Chem 1995 270: 28495–28498
Carroll MP, Spivak JL, McMahon M, Weich N, Rapp UR, May WS . Erythropoietin-induces Raf-1 activation and raf-1 is required for erythropoietin-mediated proliferation J Biol Chem 1991 266: 14964–14969
Jarvis WD, Kolesnick RN, Fornari FA, Traylor RS, Gewirtz DA, Grant S . Induction of apoptotic DNA damage and cell death by activation of the sphingomyelin pathway Proc Natl Acad Sci USA 1994 91: 73–77
Bose R, Verheij M, Haimovitz-Friedman A, Scotto K, Fuks Z, Kolesnick RN . Ceramide synthetase mediates daunorubicin-induced apoptosis: an alternative mechanism for generating death signals Cell 1995 82: 405–411
Lee JY, Hannun YA, Obeid LM . Ceramide inactivates cellular protein kinase C α J Biol Chem 1996 271: 13169–13174
Domina AM, Smith JH, Craig RW . Mcl1 is phosphorylated by two distinct pathways, one through MAP kinase and the other protein phosphatase inhibition or microtubule damage Proc Am Assoc Cancer Res 1999 40: 307
Porucynsky MS, Wang EE, Rudin CM, Blagoslonny MV, Fojo T . Bcl-XL is phosphorylated in malignant cells following microtubule disruption Cancer Res 1998 58: 3331–3338
del Peso L, Gonzalez-Garcia M, Page C, Herrera R, Nunez G . Interleukin-3-induced phosphorylation of BAD through the protein kinase Akt Science 1997 278: 687–689
Datta SR, Dudek H, Tao X, Masters S, Fu H, Gotoh Y, Greenberg ME . Akt phosphorylation of BAD couples survival signals to the intrinsic death machinery Cell 1997 91: 231–241
Harada H, Becknell B, Wilm M, Mann M, Huang LJ, Taylor SS, Scott JD, Korsmeyer SJ . Phosphorylation and inactivation of BAD by mitochondria-anchored protein kinase A Mol Cell 1999 3: 413–422
Scheid MP, Schubert KM, Duronio V . Regulation of bad phosphorylation and association with Bcl-x(L) by the MAPK/Erk kinase J Biol Chem 1999 274: 3118–3113
Yang E, Zha J, Jockel J, Bise LH, Thompson CB, Korsmeyer SJ . Bad, a heterodimeric partner for Bcl-XL and Bcl2, displaces Bax and promotes cell death Cell 1995 80: 285–291
McCubrey JA, May WS, Duronio V, Mufson A . Serine threonine phosphorylation in cytokine signal transduction Leukemia 2000 14: 9–21
Scheid MP, Duronio V . Dissociation of cytokine-induced phosphorylation of Bad and activation of PKB/akt: Involvement of MEK upstream of Bad phosphorylation Proc Natl Acad Sci USA 1998 95: 7439–7444
Zha J, Harada H, Yang E, Jockel J, Korsmeyer SJ . Serine phosphorylation of death agonist BAD in response to survival factor results in binding to 14–3-3 not Bcl-XL Cell 1996 87: 619–628
Cardone MH, Roy N, Stennicke HR, Salvesen GS, Francke T, Stanbridge E, Frisch S, Reed JC . Regulation of cell death protease caspase-9 by phosphorylation Science 1998 282: 1318–1321
Cheng EHY, Kirsch DG, Clem RJ, Ravi R, Kastan MB, Bedi A, Ueno K, Hardwick JM . Conversion of Bcl2 to a Bax-like death effector by caspases Science 1997 278: 1966–1968
Johnson BW, Boise LH . Bcl2 and caspase inhibition cooperate to inhibit tumor necrosis factor-α-induced cell death in a Bcl2 cleavage-independent fashion J Biol Chem 1999 274: 18552–18558
Clem RJ, Cheng EHY, Karp CL, Kirsch DG, Ueno K, Takahashi A, Kastan MB, Griffin DE, Earnshaw WC, Veliuona MA, Hardwick JM . Modulation of cell death by Bcl-XL through caspase interaction Proc Natl Acad Sci USA 1998 95: 554–559
Nicholson WD, Thornberry NA . Caspases: killer proteases Trends Biochem Sci 1997 257: 299–306
Liu X, Kim CN, Pohl J, Wang X . Purification and characterization of an interleukin-1b converting enzyme family of protease that activates cysteine protease p32 J Biol Chem 1996 271: 13371–13376
Liu X, Kim CN, Yang J, Jemmerson R, Wang X . Induction of apoptotic program in cell free extracts: requirement for dATP and cytochrome C Cell 1996 86: 147–157
Dimmeler S, Breitschopf K, Haendeler J, Zeiher AM . Dephosphorylation targets Bcl2 for ubiquitin-dependent degradation: a link between the apoptosome and proteasome pathway J Exp Med 1999 189: 1815–1822
Minn AJ, Kettlun CS, Liang H, Kelekar A, Vander Heiden MG, Chang BS, Fesik SW, Fill M, Thompson CB . Bcl-XL regulates apoptosis by heterodimerization-dependent and -independent mechanisms EMBO J 1999 18: 632–643
Volm M, Zintl F, Edler L, Sauerbrey A . Prognostic value of protein kinase C, proto-oncogene products and resistance-related proteins in newly diagnosed childhood acute lymphoblastic leukemia Med Ped Oncol 1997 28: 117–126
Tanaka S, Louie DC, Kant JA, Reed JC . Frequent incidence of somatic mutations in translocated Bcl2 oncogenes of non-Hodgkin's lymphomas Blood 1992 79: 229–237
Matolcsy A, Casali P, Warnke RA, Knowles DM . Morphological transformation of follicular lymphoma is associated with somatic mutation of the translocated Bcl2 gene Blood 1996 88: 3937–3944
Reed JC . Bcl2 family proteins: regulators of apoptosis and chemoresistance in hematologic malignancies Semin Hematol 1997 34: 9–19
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Ruvolo, P., Deng, X. & May, W. Phosphorylation of Bcl2 and regulation of apoptosis. Leukemia 15, 515–522 (2001). https://doi.org/10.1038/sj.leu.2402090
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DOI: https://doi.org/10.1038/sj.leu.2402090
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