Summary

SummaryThe plasminogen activator-plasmin cascade is involved inmultiple physiological and pathological processes includingfibrinolysis, wound healing, fibrosis, angiogenesis, embryo implantationand tumor cell invasion and metastasis. Plasminogenactivator-inhibitor type 1 (PAI-1) is the major physiologicalregulator of plasminogen activation. PAI-1 is expressed in avariety of mammalian cells and is regulated by growth factors,cytokines and hormones, including agents that elevate cAMPlevels. Although cyclic nucleotide regulation of PAI-1 is observed in diverse cell types in various species, including human, limitedstudies have addressed the mechanism of this regulation.Here we review our work on the regulation of PAI-1 mRNAdegradation in HTC rat hepatoma cells, describing the cis-actingcAMP-responsive sequence in the transcript and a novelRNA binding protein that interacts with it. Potential mechanismsby which this RNA-binding protein may be involved incyclic nucleotide regulation of mRNA stability are discussedand cAMP regulation of PAI-1 in other systems is summarized.