Urokinase plasminogen activator cleaves its cell surface receptor releasing the ligand-binding domain

TY - JOUR

T1 - Urokinase plasminogen activator cleaves its cell surface receptor releasing the ligand-binding domain

AU - Høyer-Hansen, G

AU - Rønne, E

AU - Solberg, H.

AU - Behrendt, N

AU - Ploug, M

AU - Lund, L R

AU - Ellis, V

AU - Danø, K

PY - 1992/9/5

Y1 - 1992/9/5

N2 - The cellular receptor for urokinase-type plasminogen activator (uPAR) is a glycolipid-anchored three-domain membrane protein playing a central role in pericellular plasminogen activation. We have found that urokinase (uPA) can cleave its receptor between domains 1 and 2 generating a cell-associated uPAR variant without ligand-binding properties. In extracts of U937 cells there are two uPAR variants which after complete deglycosylation have apparent molecular masses of 35,000 and 27,000. Analysis with monoclonal antibodies showed that these variants represented the intact uPAR and a two-domain form, uPAR(2+3), lacking ligand-binding domain 1. Trypsin treatment showed that both variants are present on the outside of the cells. Addition to the culture medium of an anticatalytic monoclonal antibody to uPA inhibited the formation of the uPAR(2+3), indicating that uPA is involved in its generation. Purified uPAR can be cleaved directly by uPA as well as by plasmin. The uPA-catalyzed cleavage does not require binding of the protease to the receptor through its epidermal growth factor-like receptor-binding domain, since low molecular weight uPA that lacks this domain also cleaves uPAR. This unusual reaction in which a specific binding protein is proteolytically inactivated by its own ligand may represent a regulatory step in the plasminogen activation cascade.

AB - The cellular receptor for urokinase-type plasminogen activator (uPAR) is a glycolipid-anchored three-domain membrane protein playing a central role in pericellular plasminogen activation. We have found that urokinase (uPA) can cleave its receptor between domains 1 and 2 generating a cell-associated uPAR variant without ligand-binding properties. In extracts of U937 cells there are two uPAR variants which after complete deglycosylation have apparent molecular masses of 35,000 and 27,000. Analysis with monoclonal antibodies showed that these variants represented the intact uPAR and a two-domain form, uPAR(2+3), lacking ligand-binding domain 1. Trypsin treatment showed that both variants are present on the outside of the cells. Addition to the culture medium of an anticatalytic monoclonal antibody to uPA inhibited the formation of the uPAR(2+3), indicating that uPA is involved in its generation. Purified uPAR can be cleaved directly by uPA as well as by plasmin. The uPA-catalyzed cleavage does not require binding of the protease to the receptor through its epidermal growth factor-like receptor-binding domain, since low molecular weight uPA that lacks this domain also cleaves uPAR. This unusual reaction in which a specific binding protein is proteolytically inactivated by its own ligand may represent a regulatory step in the plasminogen activation cascade.

KW - Antibodies, Monoclonal

KW - Aprotinin

KW - Binding Sites

KW - Blotting, Western

KW - Cell Line

KW - Electrophoresis, Polyacrylamide Gel

KW - Fibrinolysin

KW - Humans

KW - Kinetics

KW - Ligands

KW - Lymphoma, Large B-Cell, Diffuse

KW - Receptors, Cell Surface

KW - Receptors, Urokinase Plasminogen Activator

KW - Tetradecanoylphorbol Acetate

KW - Trypsin

KW - Urokinase-Type Plasminogen Activator

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

M3 - Journal article

C2 - 1381366

SN - 0021-9258

VL - 267

SP - 18224

EP - 18229

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

IS - 25

ER -