- Email: [email protected]
Calcium as an intracellular messenger in eucaryotic microbes
625
Literature
Molecular and Cell Biology of Membrane Proteins, edited by AJ Turner, Ellis Horwood, 1990, pp 220 A new field in membrane structure and function has recently emerged from the discovery of a number of surface proteins attached to the plasma membrane by a new type of anchor: instead of the classical hydrophobic membrane-spanning 0thelices, these proteins have a glycosyl-phosphatidyl inositoi (GPI) anchor. This particular type of post-translational modification of membrane proteins occurs in the endoplasmid reticulum, where a hydrophobic carboxyl-terminus segment of the precursor molecule, utilized both as a signal sequence and as a transitory anchor, is cleaved and replaced by preformed GPI blocks which become the anchors of the mature proteins. The number of membrane proteins shown to possess a GPI anchor is continuously increasing. In protozoa, GPI proteins generally constitute major surface antigens in both pathogenic (Tlypanosoma, Leishmania) and non pathogenic (Paramecium) specms. The African trypanosome variable surface glycoproteins (VSGs) are the best analyzed GPI proteins. They m-e the first molecules whose primary and 3-dimensional structures have been completely elucidated. In metazao, numerous GPIanchored proteins have been described. They are implicated in important biological functions as surface enzymes (acetylcholinesterase, alkaline phosphatase, renal dipeptidase, trehalase), cellular activators (Thy-l, Ly-6 antigens, T cell activating protein) and proteins involved in cellular or extracellular matrix adhesion (LFA-3, neural cell adhesion molecule, integrins) or miscellaneous functions as decay accelerating factor and Scrapie prion protein. At the same time as GPI anchored proteins were found, specific enzymes (glycan-inositol phospholipase C or D) capable of cleaving the lipid part of molecules and releasing the soluble proteins were also discovered. In fact, the cleaved !i~id r,arts (diacvl ~lvcerols) of the GPI proteins could play a role as seconcl messengers in ceil physiology. The numerous aspects of the GPI anchored proteins and of their specific phospholipases are described in this book by leading scientists in the field. A detailed analysis of the glycolipid structure, biosynthesis and transport of lipid-a:lchored membrane proteins is presented. The role of glycosyiphosphoinositides in signal transduction is also discussed and one chapter is devoted to the puzzling prion protein responsible for Scrapie disease. The clarity of the presentation makes this book accessible to all scientists. Furthermore, it offers excellent and up-to-date information which will be a most valuable source of reference, and numerous experimental indications for researchers dealing with GPI-anchored p.oteins. Y Capdeville
Calcium as an Intracellular Messenger in Eucaryotic Microbes, edited by DH O'Day, American Society for Microbiology, 1990, pp xi + 418, $ 72.00 ($ 54.00 for members) The fundamental role of the ubiquitous divalent calcium cation as intracellular messenger operating within a wide range of extremely different physiological or metabolical events is
ample justification for the increasing number of publications and reviews such as the one edited by DH O'Day. Although the book is limited to unicellular eucaryotes, it offers a collection of no less than 22 minireviews based on the results of the most recent experiments performed by their authors. This means that the subject is examined under very different aspects, from the role of calcium upon membrane excitation in Paramecium to its role in circadian timekeeping and the rhythm of cell devision in Euglena. Most chapters describe the various effects of the inositolphosphate cycle triggered off by extracellular signals. They examine the role of Ca "+ in those effects and also the numerous consequences of its interaction with calmodulin or other Cabinding proteins. Other chapters aptly complete this review by indicating less developed aspects: calcium- and phospholipid-dependent protein and lipid kinases in Neurospora crassa or intracellular calcium during mating in the green alga Chlamydomonas reinhardtii. It is to be noted that in the chapter on proliferation of yeast cells, calcium is not mentioned in any detail. Yet by highlighting the interactioa between the activity of adenylate cyclase and that of Pl-phospholipase C, this chapter leads the reader to form a series of questions concerning the emergence of new secondary messengers during evolution, organic messengers this time, to complete or act as a substitute to the original function(s) of Ca "+. Since each chapter is devoted to a unique organim and covers one of a range of diverse biological problems such as growth, division, differentiation, morphogenesis, mating etc. the reader obtains an insight into the specific cellular activity presented and at the same time gains a broader understanding about calcium as an intracellular messenger in eucaryotes. Obviously this book provides interesting subject matter for the scientific community and should find wide audience among those interested in the proces; of life and the underlying molecular mechanisms related to their regulation. B Lubochinsky
Sensors in Bioprocess Control, edited by JVTwork, AM Yacynych, Marcel Dekker, 1990, pp 440, $ 115.00 (US and Canada) or $138.00 (all other countries). While the history of the fermentation industry has made the general public familiar with strain isolation, improvement of the strains and gene cloning, this is only the tip ot the iceberg. As soon as the living cell is used to obtain products under satisfactory conditions, a coherent line of operation is required. One of the keys to this is obtaining reliable sensors in order to provide reproducible and optimal conditions for the growth and induction of cells during fermentation. A book covering the state of the art in the field of "sensors in bioprocess control' should be considered as a useful contribution at a time when most biotechnology products are in their infancy.
Literature
Molecular and Cell Biology of Membrane Proteins, edited by AJ Turner, Ellis Horwood, 1990, pp 220 A new field in membrane structure and function has recently emerged from the discovery of a number of surface proteins attached to the plasma membrane by a new type of anchor: instead of the classical hydrophobic membrane-spanning 0thelices, these proteins have a glycosyl-phosphatidyl inositoi (GPI) anchor. This particular type of post-translational modification of membrane proteins occurs in the endoplasmid reticulum, where a hydrophobic carboxyl-terminus segment of the precursor molecule, utilized both as a signal sequence and as a transitory anchor, is cleaved and replaced by preformed GPI blocks which become the anchors of the mature proteins. The number of membrane proteins shown to possess a GPI anchor is continuously increasing. In protozoa, GPI proteins generally constitute major surface antigens in both pathogenic (Tlypanosoma, Leishmania) and non pathogenic (Paramecium) specms. The African trypanosome variable surface glycoproteins (VSGs) are the best analyzed GPI proteins. They m-e the first molecules whose primary and 3-dimensional structures have been completely elucidated. In metazao, numerous GPIanchored proteins have been described. They are implicated in important biological functions as surface enzymes (acetylcholinesterase, alkaline phosphatase, renal dipeptidase, trehalase), cellular activators (Thy-l, Ly-6 antigens, T cell activating protein) and proteins involved in cellular or extracellular matrix adhesion (LFA-3, neural cell adhesion molecule, integrins) or miscellaneous functions as decay accelerating factor and Scrapie prion protein. At the same time as GPI anchored proteins were found, specific enzymes (glycan-inositol phospholipase C or D) capable of cleaving the lipid part of molecules and releasing the soluble proteins were also discovered. In fact, the cleaved !i~id r,arts (diacvl ~lvcerols) of the GPI proteins could play a role as seconcl messengers in ceil physiology. The numerous aspects of the GPI anchored proteins and of their specific phospholipases are described in this book by leading scientists in the field. A detailed analysis of the glycolipid structure, biosynthesis and transport of lipid-a:lchored membrane proteins is presented. The role of glycosyiphosphoinositides in signal transduction is also discussed and one chapter is devoted to the puzzling prion protein responsible for Scrapie disease. The clarity of the presentation makes this book accessible to all scientists. Furthermore, it offers excellent and up-to-date information which will be a most valuable source of reference, and numerous experimental indications for researchers dealing with GPI-anchored p.oteins. Y Capdeville
Calcium as an Intracellular Messenger in Eucaryotic Microbes, edited by DH O'Day, American Society for Microbiology, 1990, pp xi + 418, $ 72.00 ($ 54.00 for members) The fundamental role of the ubiquitous divalent calcium cation as intracellular messenger operating within a wide range of extremely different physiological or metabolical events is
ample justification for the increasing number of publications and reviews such as the one edited by DH O'Day. Although the book is limited to unicellular eucaryotes, it offers a collection of no less than 22 minireviews based on the results of the most recent experiments performed by their authors. This means that the subject is examined under very different aspects, from the role of calcium upon membrane excitation in Paramecium to its role in circadian timekeeping and the rhythm of cell devision in Euglena. Most chapters describe the various effects of the inositolphosphate cycle triggered off by extracellular signals. They examine the role of Ca "+ in those effects and also the numerous consequences of its interaction with calmodulin or other Cabinding proteins. Other chapters aptly complete this review by indicating less developed aspects: calcium- and phospholipid-dependent protein and lipid kinases in Neurospora crassa or intracellular calcium during mating in the green alga Chlamydomonas reinhardtii. It is to be noted that in the chapter on proliferation of yeast cells, calcium is not mentioned in any detail. Yet by highlighting the interactioa between the activity of adenylate cyclase and that of Pl-phospholipase C, this chapter leads the reader to form a series of questions concerning the emergence of new secondary messengers during evolution, organic messengers this time, to complete or act as a substitute to the original function(s) of Ca "+. Since each chapter is devoted to a unique organim and covers one of a range of diverse biological problems such as growth, division, differentiation, morphogenesis, mating etc. the reader obtains an insight into the specific cellular activity presented and at the same time gains a broader understanding about calcium as an intracellular messenger in eucaryotes. Obviously this book provides interesting subject matter for the scientific community and should find wide audience among those interested in the proces; of life and the underlying molecular mechanisms related to their regulation. B Lubochinsky
Sensors in Bioprocess Control, edited by JVTwork, AM Yacynych, Marcel Dekker, 1990, pp 440, $ 115.00 (US and Canada) or $138.00 (all other countries). While the history of the fermentation industry has made the general public familiar with strain isolation, improvement of the strains and gene cloning, this is only the tip ot the iceberg. As soon as the living cell is used to obtain products under satisfactory conditions, a coherent line of operation is required. One of the keys to this is obtaining reliable sensors in order to provide reproducible and optimal conditions for the growth and induction of cells during fermentation. A book covering the state of the art in the field of "sensors in bioprocess control' should be considered as a useful contribution at a time when most biotechnology products are in their infancy.