Coordinate secretion and functional synergism of T cell-associated serine proteinase-1 (MTSP-1) and endoglycosidase(s) of activated T cells.
Cell lysates and exocytosed soluble mediator(s) (ESM) released from CD8+ T cell lines (TCL) by receptor-triggered secretory exocytosis were tested for degradation of proteoglycans associated with in vitro produced subendothelial extracellular matrix (ECM). ESM was found to release low-molecular weight (kav 0.5-0.6) fragments from the sulfated proteoglycans in ECM. In the presence of heparin, an inhibitor for endoglycosidase activity, only high-molecular-weight products (kav 0.2) were formed. Preincubation of ESM with HD-prolylphenylalanyl-arginyl-chloromethylketone (PFR-CK) an inhibitor for the T cell-associated serine proteinase-1 (MTSP-1) totally prevented release of high- and low-molecular weight proteoglycan fragments. Furthermore, it was shown that purified MTSP-1 is able to release from ECM high-molecular weight proteoglycans and that this process is inhibitable by PFR-CK but not by heparin. Further treatment of these soluble high-molecular weight sulfated proteoglycans with ESM from TCL 1.D9 led to appearance of low-molecular weight split products (kav 0.5-0.6). This conversion was inhibitable by heparin but not by PFR-CK. These findings indicate that activated T cells contain two enzymatic activities, i.e. MTSP-1 and at least one endoglycosidase, which after receptor-triggered secretion can synergize in the degradation of sulfated proteoglycans in subendothelial ECM.
Vettel
U
U
Institut für Immunologie und Serologie, Heidelberg, FRG.
Bar-Shavit
R
R
Simon
M M
MM
Brunner
G
G
Vlodavsky
I
I
Kramer
M D
MD
D000818:Animals; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006026:Glycoside Hydrolases / Q000378:metabolism / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011509:Proteoglycans / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000201:enzymology*
D011509:Proteoglycans; D006026:Glycoside Hydrolases