Edited by K. B. Storey and J. M. Storey Elsevier Science (2001) pp. 312. ISBN SBN 0-444-50759-0 [UNK]179, $179
The field of comparative physiology and biochemistry has benefited greatly from molecular techniques first developed for biomedical and cellular research involving model organisms. The ability to clone and sequence genes and quantify levels of gene expression has provided powerful tools for understanding how organisms adapt to diverse environmental challenges. Yet this transfer of information is not a one-way street. Comparative studies provide vital contributions to the basic understanding of cellular function at the heart of biomedical research. In volume 2 of the series `Cell and Molecular Responses to Stress', editors Kenneth and Janet Storey compile 20 review papers that invite further integration of these two areas of science.
The volume pursues two broad themes. The first, adaptation of proteins for stress tolerance, is a mainstay of comparative biochemistry. But the second theme, that of the transduction pathways between stresses and the resulting changes in gene expression, is a newer pursuit. This fact is reflected by the predominance of non-comparative studies on model organisms included in this volume. The greatest contribution of this book is to provide the comparative biologist with a current summary of the exploding knowledge of receptors,kinases and transcription factors involved in stress transduction. The few comparative studies included in this volume provide a roadmap for the comparative biologist to take advantage of this vast amount of new information to contribute to the understanding of how cells respond to stress.
The power of the comparative approach in studying both protein adaptation and signal transduction is beautifully illustrated by the first chapter of this volume in which Storey and Storey describe their research on freeze tolerance in wood frogs. Differential screening of cDNA libraries led the authors to identify genes upregulated during freezing, including those for fibrinogen, ADP/ATP translocase and one novel peptide. The next challenge is to determine the functions of these gene products. The authors hypothesize that fibrinogen may help to repair tissue damage caused by ice formation during freezing, and ADP/ATP translocase may be important in a general change in mitochondrial energy metabolism. The authors leave this chapter with a fascinating look at how freeze-tolerant frogs use hyperglycemia to lower the melting point of their tissues. They identify changes in insulin structure and kinase function that may lead to decreased glucose metabolism at low temperature, thus leading to elevated glucose levels. Most of the other papers in this volume lack this integrative approach, and focus on either protein adaptation or signal transduction in various model organisms.
A mixture of topics related to freeze-tolerance and cold-adapted proteins are discussed in the next section of the volume. Duncker et al. describe the use of Drosophila for the transgenic expression of fish antifreeze proteins. D'Amico et al. discuss their use of random mutagenesis to produce enzymes with both high catalytic activity at low temperature and high global thermal stability. The authors conclude that decreased global stability is not a requirement for low temperature function, but rather the result of a lack of selection in cold-tolerant organisms for thermal stability. The uncoupling of catalytic activity and thermal stability has been shown in comparative studies as well, demonstrating the value of using both mutagenesis and naturally occurring variations to study protein adaptation. Wouters et al. discuss the freeze-protective role of bacterial cold-shock proteins as transcriptional activators and RNA chaperones. Rubtsov provides a thorough review of changes in gene expression and protein phosphorylation during mammalian hibernation. Somewhat isolated in this section of the book is an interesting chapter by Van Hoeck et al. that takes a comparative approach to the study of water stress and water channels (aquaporins) by examining water transport physiology in the kidney of the desert kangaroo rat.
The next few chapters cover cellular responses to mechanical stress and nutritional level. Goldspink and Yang describe how mechanical stress leads to changes in myosin heavy chain gene expression. Chiquet and Fluck examine how mechanical strain induces cellular signaling through the activity of membrane-bound ion channels and integrin proteins bound to the extracellular matrix. The physiological changes that occur during fasting and the way that the nutritional level induces changes in hepatic gene expression are covered in separate chapters by Brooks and Towle.
Three very well-written chapters focus on different families of kinases. Hardie describes how the AMPK/SNF1 protein kinase system is used to respond to metabolic stress in fungi, animals and plants. Newton and Toker discuss the important role of Protein Kinase C (PKC) in controlling apoptosis through its regulation of caspases. One of the central kinase systems involved in stress-transduction, the mitogen-activated protein kinase superfamily (MAPK),is ably detailed by Hoeflich and Woodgett. This is no easy challenge considering that over 100 of these serine-dependent kinases have been sequenced so far. The sheer amount of new information in these three chapters indicates the importance of these kinase systems in current cell biology research. These systems will likely play an increasingly central role in the examination of stress response by comparative biologists.
The final chapters in this volume examine cellular responses to hypoxia and oxidative stress. Topics covered include the role of oxygen-sensitive ion channels in cellular response to hypoxia (Peers), the role of the transcription factors Nrf1 and Nrf2 in oxidative stress defense (Bloom et al.)and the response to reactive oxygen species by vascular tissues (Jin and Berk). Chakraborti et al. provide a fascinating view of the many ways that changing Ca2+ levels during oxidative stress signal responses in the cell. The diverse effects of oxidative stress on kinase cascades,transcriptional regulation and apoptosis are covered by Habelhah and Ronai. The volume concludes with an examination by Hermes-Lima et al. of antioxidant defense in a wide range of anoxia-tolerant vertebrates. By examining extreme cases of natural hypoxia this comparative study illustrates how tissues survive the increase in oxidative stress produced by ischemia and subsequent reperfusion.
A few negative aspects to this volume need mentioning. While the quality of writing of most of the chapters is excellent, a few suffer from confusing organization. Only a handful of the chapters attempt to integrate the two themes of protein adaptation and stress-transduction, giving this volume somewhat of a split personality. And as mentioned above, only a few chapters describe comparative research. This last point is not necessarily a negative,as the purpose of this volume appears to be an invitation to direct the comparative approach to topics primarily studied by non-comparative cell biologists.
I would strongly recommend this book to anyone interested in a current description of the molecular mechanisms that allow cells to react to stress. The chapters on kinase systems and their involvement in transduction pathways are important reading for any comparative biologist interested in stress. Any thorough analysis of stress response will need to integrate this new wealth of molecular information. Furthermore, the descriptions of how cells sense and respond to diverse stresses can provide valuable insights to anyone thinking about stress response. At the same time, the few chapters that use comparative approaches underscore the valuable contributions to be made by examining a diversity of naturally evolved stress transduction systems.
