The undecided serpin. The ins and outs of plasminogen activator inhibitor type 2.
Plasminogen activator inhibitor type-2 (PAI-2) is a nonconventional serine protease inhibitor (serpin) with unique and tantalizing properties that is generally considered to be an authentic and physiological inhibitor of urokinase. However, the fact that only a small percentage of PAI-2 is secreted has been a long-standing argument for alternative roles for this serpin. Indeed, PAI-2 has been shown to have a number of intracellular roles: it can alter gene expression, influence the rate of cell proliferation and differentiation, and inhibit apoptosis in a manner independent of urokinase inhibition. Despite these recent advances in defining the intracellular function of PAI-2, it still remains one of the most mysterious and enigmatic members of the serpin superfamily.
Medcalf
Robert L
RL
Australian Centre for Blood Diseases, Monash University, Prahran, Victoria, Australia. Robert.medcalf@med.monash.edu.au
Stasinopoulos
Stan J
SJ
D000818:Animals; D017209:Apoptosis; D005786:Gene Expression Regulation; D006801:Humans; D009362:Neoplasm Metastasis / Q000473:pathology; D017396:Plasminogen Activator Inhibitor 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D017396:Plasminogen Activator Inhibitor 2; D015842:Serine Proteinase Inhibitors