Interactions Among Cell Signalling Systems Chairman: Y. Nishizuka 1992 The study of mechanisms of cell signalling, including the processes involved in signal transduction, is one of the most exciting and dynamic areas of biological research. As the mechanisms of cell signalling systems have become known in more detail, the importance of interactions between them??‘cross–talk’??has emerged. Interactions are seen at various levels of receptors, ion channels, coupling factors, second messengers and effectors. The subject of this book is cross–talk and its functional implications for mechanisms of hormone action, synaptic activity, the immune system, gene expression and growth control. The actions of and interactions between various types of protein kinases are a particular feature. There is discussion of the involvement of tyrosine kinases and the recently identified tyrosine phosphatases in growth control and the immune system. Protein kinase C activity in T cell activation mechanisms, stimulation of the enzyme by the synergistic action of diacylglycerol and unsaturated fatty acids, and the role and localization of protein kinase C subspecies are considered. The convergence of the protein kinase C and Ca 2+/calmodulin signal transduction pathways in the control of cytoskeletal??plasma membrane interactions by regulation of the MARCKS protein is described. The roles of GABA and NMDA receptors, calcium, protein kinase C and calmodulin–dependent protein kinase in the mechanisms underlying long–term potentiation are analysed. Other topics covered include G protein regulation of phosphoinositide and phosphatidylcholine phospholipases, growth factor tyrosine phosphorylation of phospholipase C–??1, the interaction between the Ca 2+ and cyclic AMP second messenger systems in the regulation of insulin secretion and that between cyclic AMP and inositol lipids in activation of B cells. Related Ciba Foundation Symposia: No. 122 Calcium and the cell Chairman: P.F. Baker 1986 ISBN 0 471 91088 0 No. 150 Proto–oncogenes in cell development Chairman: T. Hunter 1990 ISBN 0 471 92686 8 No. 52 The biology of nicotine dependence Chairman: L. L. Iversen 1990 ISBN 0 471 92688 4