Review
Protein kinases and their involvement in the cellular responses to genotoxic stress

https://doi.org/10.1016/S1383-5742(02)00069-8Get rights and content

Abstract

Cells are constantly subjected to genotoxic stress, and much has been learned regarding their response to this type of stress during the past year. In general, the cellular genotoxic response can be thought to occur in three stages: (1) damage sensing; (2) activation of signal transduction pathways; (3) biological consequences and attenuation of the response. The biological consequences, in particular, include cell cycle arrest and cell death. Although our understanding of the molecular mechanisms underlying cellular genotoxic stress responses remains incomplete, many cellular components have been identified over the years, including a group of protein kinases that appears to play a major role. Various DNA-damaging agents can activate these protein kinases, triggering a protein phosphorylation cascade that leads to the activation of transcription factors, and altering gene expression. In this review, the involvement of protein kinases, particularly the mitogen-activated protein kinases (MAPKs), at different stages of the genotoxic response is discussed.

Introduction

Throughout their life cycle, cells are constantly subjected to many and varied stressors. These stressors include starvation, infection, changes in their physical or chemical condition (for example, heat, cold, or pH), and genotoxic damage. Stress can be generated by both endogenous and exogenous sources. Endogenous sources would include the products of oxidative metabolic reactions, while exogenous sources could include ultraviolet (UV) light, ionizing radiation (IR), and DNA-damaging chemicals. To ensure normal growth control and accuracy in DNA replication, cells have developed a variety of responses to stress, and several signal transduction pathways function to execute these responses. Although the mechanisms underlying are incompletely understood, it is clear that the network of responses is very complex. Currently, many studies in multiple disciplines are seeking to explore and elucidate the mechanisms of the cellular responses to stress, resulting in the definition of some of the signal transduction pathways and cellular components (reviewed in [1], [2], [3], [4], [5]).

The cellular targets of stressors are primarily proteins and DNA. The heat shock response is probably the most studied cellular event that copes with protein-damaging stresses. Following a stress such as heat, several heat shock proteins (HSPs) are mobilized. These HSPs protect functional proteins from irreversible denaturation caused by heat and other stresses and assist them in renaturation. Other mechanisms, such as the son of sevenless (SOS) response in prokaryotes and the DNA repair system in eukaryotes, are used to deal with DNA-damaging stresses such as IR. Genotoxic stress, or damage to DNA, is regularly encountered by cells. Such stress can be induced by exposure to UV- or γ-irradiation, environmental chemicals or therapeutic reagents. Exposure of cells to such genotoxic agents initiates a series of events leading to the activation of a wide group of genes with diverse functions [6], [7]. Among these are a group of transcription factors as well as other gene products that can also be rapidly induced in response to mitogenic stimulation. Their dual functions illustrate the commonalities of the pathways involved in mediating the cellular responses to stress and to proliferative signals.

Given the large number of agents that damage DNA, the diversity of these agents with respect to their structures and mechanisms of action, and their ability to inflict damage on cellular components other than DNA, it is not surprising that the genotoxic response is a very complex process, involving multiple signaling pathways that exist in parallel and “cross-talk” with each other to mediate the final outcome. To simplify the issue, the cellular response to genotoxic stress can be divided into three major components [8]:

  • (1)

    Damage-sensing and signal-initiating events: The damage inflicted by genotoxic stress, mainly to the DNA, acts as the initiating signal. Several “sensors” then perceive the damage and initiate subsequent events.

  • (2)

    Signal transduction: The signal from the sensors is passed down through a number of signal transduction pathways, which are composed primarily of protein kinases that are activated through phosphorylation. This then leads to the activation of transcription factors, which in turn enhances the expression of certain genes that are involved in events such as DNA repair, cell cycle arrest, or cell death.

  • (3)

    Biological consequences and attenuation of the response: For a unicellular organism, repair of damaged DNA is the best way to ensure survival. Even if some damage is not repaired, the cell may still be able to continue functioning and even replicating. In metazoans, however, the optimal strategy to deal with DNA damage is not as simple, as survival of the organism may be enhanced by the loss of cells otherwise viable but with damaged DNA. Mutations in genes that are important in controlling cell growth, differentiation, and proliferation are the major cause of neoplasms which can lead to death of the organism. Therefore, it may be safer for the organism as a whole to eliminate the damaged cells. As a result, repair, growth arrest, and cell suicide (apoptosis) are all possible outcomes of the cellular response to genotoxic stress in metazoans, and the choice will depend on the cell type, location, environment, and extent of damage [9]. The activation of signal transduction pathways also enhances the expression of certain genes that can attenuate the response. For example, the protein kinase cascade activates the expression of certain phosphatases. Also, the tumor suppressor p53 protein, as a transcription factor, also activates the expression of mouse double minute 2 (MDM2), an intracellular regulator of ubiquitin-mediated degradation of p53. Therefore, a negative feedback regulation system exists in the cellular response to genotoxic stress.

Some of the key players involved in these events are well defined. One classic example is p53, which has such an important role in the genotoxic stress response that it has been called the “universal sensor for genotoxic stress” [10], [11]. Other molecules are also emerging as important regulators of the genotoxic response and have gained increasing recognition in the past several years. One such example is ceramide, a member of the sphingolipid family [12], [13]. In this review, we focus on the protein kinases and the roles they play in damage sensing and signal transduction, and finally, the attenuation of the kinases.

Section snippets

DNA damage as the initiation signal

Evidence accumulated over the years indicates that DNA damage is the most important signal for the induction of the genotoxic stress responses [14], [15], [16]. For example, DNA double-strand breaks (DSBs) can be induced by IR or other genotoxic agents, or even during the V(D)J recombination of immune system, and this can lead to activation of DNA-dependent protein kinase (DNA-PK) [17]. Direct damage to DNA, especially in the form of strand breaks, also activates the tumor suppressor p53

The downstream protein kinase cascade

To date, multiple signal transduction pathways have been shown to be involved in the cellular response to genotoxic stress, and additional components are constantly being identified. Most of these pathways involve the activation of protein kinases, which include the non-receptor tyrosine kinase c-Abl [89], Lyn [90], [91], [92], [93], and members of the mitogen-activated protein kinase (MAPK) family [94], [95], [96], [97], [98]. These kinases play a key role in the activation of transcription

Biological consequences and regulation of the kinases

As mentioned earlier, the activation of signal transduction pathways by genotoxic stress leads to several possible outcomes, such as cell cycle arrest, which allows repair of the damaged DNA, or when the damage is too severe and cannot be repaired, apoptosis. However, a key issue remain unsolved is how the cell decides if the damage is severe enough and thus to shift from repair to apoptosis. Although no plausible mechanism has been proposed, it seems likely that those DNA damage sensors (such

Conclusions

The cellular response to genotoxic stress is a very complex process. It begins with the detection of DNA damage and ends with DNA repair or cell death, and involves numerous components in multiple signal transduction pathways. A general scheme is that several sensors detect the DNA damage caused by genotoxic agents, and this signal triggers signal transduction pathways, in which the MAPK pathways play the most prominent role. This then leads to the activation of transcription factors, resulting

Acknowledgements

We the authors gratefully thank Dr. D. DeMarini and the anonymous reviewers for their valuable suggestions that greatly improved this manuscript.

References (366)

  • M. Hekmat Nejad et al.

    Xenopus ATR is a replication-dependent chromatin-binding protein required for the DNA replication checkpoint

    Curr. Biol.

    (2000)
  • K. Suzuki et al.

    Recruitment of ATM protein to double strand DNA irradiated with ionizing radiation

    J. Biol. Chem.

    (1999)
  • G.D. Kim et al.

    Sensing of ionizing radiation-induced DNA damage by ATM through interaction with histone deacetylase

    J. Biol. Chem.

    (1999)
  • Y. Shiloh

    ATM and ATR: networking cellular responses to DNA damage

    Curr. Opin. Genet. Dev.

    (2001)
  • B.-B. Zhou et al.

    Caffeine abolishes the mammalian G2/M DNA damage checkpoint by inhibiting ataxia-telangiectasia-mutated kinase activity

    J. Biol. Chem.

    (2000)
  • S. Kishi et al.

    A critical role for Pin2/TRF1 in ATM-dependent regulation. Inhibition of Pin2/TRF1 function complements telomere shortening, radiosensitivity, and the G(2)/M checkpoint defect of ataxia-telangiectasia cells

    J. Biol. Chem.

    (2002)
  • S. Kishi et al.

    Telomeric protein Pin2/TRF1 as an important ATM target in response to double strand DNA breaks

    J. Biol. Chem.

    (2001)
  • M.J. Chen et al.

    ATM-dependent phosphorylation of human Rad9 is required for ionizing radiation-induced checkpoint activation

    J. Biol. Chem.

    (2001)
  • I.M. Ward et al.

    Histone H2AX is phosphorylated in an ATR-dependent manner in response to replicational stress

    J. Biol. Chem.

    (2001)
  • S. Burma et al.

    ATM phosphorylates histone H2AX in response to DNA double-strand breaks

    J. Biol. Chem.

    (2001)
  • T.M. Gottlieb et al.

    The DNA-dependent protein kinase: requirement for DNA ends and association with Ku antigen

    Cell

    (1993)
  • K. Hartley et al.

    DNA-dependent protein kinase catalytic subunit: a relative of phosphatidylinositol 3-kinase and the ataxia telangiectasia gene product

    Cell

    (1995)
  • R. Kanaar et al.

    Molecular mechanisms of DNA double-strand break repair

    Trends Cell Biol.

    (1998)
  • S.E. Critchlow et al.

    DNA end joining: from yeast to man

    Trends Biochem. Sci.

    (1998)
  • G. Chu

    Double-strand break repair

    J. Biol. Chem.

    (1997)
  • J. Huang et al.

    Heat shock transcription factor 1 binds selectively in vitro to Ku protein and the catalytic subunit of the DNA-dependent protein kinase

    J. Biol. Chem.

    (1997)
  • P.A. Jeggo

    DNA-PK: at the cross-roads of biochemistry and genetics

    Mutat. Res.

    (1997)
  • N.O. Karpinich et al.

    The course of etoposide-induced apoptosis from damage to DNA and p53 activation to mitochondrial release of cytochrome C

    J. Biol. Chem.

    (2002)
  • S. Kharbanda et al.

    Activation of the Src-like p56/p53Lyn tyrosine kinase by ionizing radiation

    J. Biol. Chem.

    (1994)
  • M.J. Pillaire et al.

    Cisplatin and UV radiation induce activation of the stress-activated protein kinase p38gamma in human melanoma cells

    Biochem. Biophys. Res. Commun.

    (2000)
  • D. Uberti et al.

    Epithelial cells of different organs exhibit distinct patterns of p53-dependent and p53-independent apoptosis following DNA insult

    Exp. Cell Res.

    (1999)
  • G.S. Dbaibo

    Regulation of the stress response by ceramide

    Biochem. Soc. Trans.

    (1997)
  • U. Feige, R.I. Morimoto, I. Yahara, B.S. Polla, Stress-Inducible Cellular Responses, Birkhauser, Basel, Switzerland,...
  • R.E. Shackelford et al.

    Cell cycle control, checkpoint mechanisms, and genotoxic stress

    Environ. Health Perspect.

    (1999)
  • X. Wang et al.

    p53-dependent signal transduction induced by stress

    J. Radiat. Res.

    (1997)
  • N.J. Holbrook et al.

    Response to adversity: molecular control of gene activation following genotoxic stress

    New Biologist

    (1991)
  • N.J. Holbrook, Y. Liu, A.J. Fornace, Signaling events controlling the molecular response to genotoxic stress, in: U....
  • G. Even et al.

    A matter of life and cell death

    Science

    (1998)
  • J. Yang et al.

    A new approach to identifying genotoxic carcinogens: p53 induction as an indicator of genotoxic damage

    Carcinogenesis

    (1998)
  • W.D. Jarvis et al.

    The role of ceramide in the cellular response to cytotoxic agents

    Curr. Opin. Oncol.

    (1998)
  • D.B. Yarosh et al.

    Cyclobutane pyrimidine dimers in UV-DNA induce release of soluble mediators that activate the human immunodeficiency virus promoter

    J. Invest. Dermatol.

    (1993)
  • J.D. Luethy et al.

    Activation of the gadd153 promoter by genotoxic agents: a rapid and specific response to DNA damage

    Cancer Res.

    (1992)
  • S. Gibbs et al.

    Characterization of the human spr2 promoter: induction after UV irradiation or TPA treatment and regulation during differentiation of cultured kereinocytes

    Nucleic Acids Res.

    (1990)
  • G.C.M. Smith et al.

    The DNA-dependent protein kinase

    Genes Dev.

    (1999)
  • J. Jayaraman et al.

    Activation of p53 sequence-specific DNA binding by short single strand of DNA requires the p53 C-terminus

    Cell

    (1995)
  • W.G. Nelson et al.

    DNA strand breaks: the DNA template alterations that trigger p53-dependent DNA damage response pathways

    Mol. Cell. Biol.

    (1994)
  • Q. Zhan et al.

    Similarity of the DNA-damaging responsiveness and growth suppressive properties of WAF1 to GAD45

    Int. J. Oncol.

    (1995)
  • Y. Devary et al.

    NF-κB activation by ultraviolet light not dependent on a nuclear signal

    Science

    (1993)
  • C.A. Stein

    Suramin: a novel antineoplastic agent with multiple potential mechanisms of action

    Cancer Res.

    (1993)
  • V. Adler et al.

    Role of redox potential and reactive oxygen species in stress signaling

    Oncogene

    (1999)

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