Adaptation in cyclic AMP signalling processes: a central role for cyclic AMP phosphodiesterases.

Cyclic AMP has provided the paradigm for the second messenger concept. Recent evidence has identified a complex array of isoforms of the enzymes involved in generation, destroying and transmitting the effects of this second messenger. These proteins provide a sophisticated system for organising cAMP signal transduction in specific intracellular compartments; for allowing integration with other signalling systems and for controlling the kinetics and hence reaction characteristics of cAMP signal transduction.