title: The plasminogen activation system and the regulation of catecholaminergic function.
abstract: The local environment of neurosecretory cells contains the major components of the plasminogen activation system, including the plasminogen activators, tissue plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA), as well as binding sites for t-PA, the receptor for u-PA (uPAR), and also the plasminogen activator inhibitor, PAI-1. Furthermore, these cells express specific binding sites for plasminogen, which is available in the circulation and in interstitial fluid. Colocalization of plasminogen and its activators on cell surfaces provides a mechanism for promoting local plasminogen activation. Plasmin is retained on the cell surface where it is protected from its inhibitor, α(2)-antiplasmin. In neurosecretory cells, localized plasmin activity provides a mechanism for extracellular processing of secreted hormones. Neurotransmitter release from catecholaminergic cells is negatively regulated by cleavage products formed by plasmin-mediated proteolysis. Recently, we have identified a major plasminogen receptor, Plg-R(KT). We have found that Plg-R(KT) is highly expressed in chromaffin cells of the adrenal medulla as well as in other catecholaminergic cells and tissues. Plg-R(KT)-dependent plasminogen activation plays a key role in regulating catecholaminergic neurosecretory cell function.
authors.affiliation: Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Hongdong
authors.initials: H
authors.lastname: Bai
authors.forename: Samir
authors.initials: S
authors.lastname: Nangia
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Parmer
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D025461:Feedback, Physiological / Q000502:physiology; D006801:Humans; D009490:Neurosecretory Systems / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D010960:Plasminogen Activators / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D010958:Plasminogen; D010960:Plasminogen Activators