SUBTYPES OF THE TYPE-4 CAMP PHOSPHODIESTERASES - STRUCTURE, REGULATION AND SELECTIVE-INHIBITION

The 'famille nombreuse' of cyclic nucleotide phosphodiesterases, respo nsible for degrading the ubiquitous second messenger molecules, cAMP a nd cGMP, maintains its place as a major focus of interest for many res earch laboratories in both academia and industry. The increase in know ledge of the primary sequences, plus the availability of selective inh ibitors, are rapidly improving our insight into the structure, regulat ion and function of these pivotal enzymes of cellular homeostasis. Her e, Thomas Muller, Peter Engels and John Fozard focus on family 4 of th e phosphodiesterases, which is of particular interest owing to both th e number of genes (and splice variants) and the emergence of selective inhibitors, which are enabling the functional significance of these e nzymes to be defined.