Comparative studies on insulin-like growth factor II and insulin processing by vascular endothelial cells

Diabetes ◽  
1986 ◽  
Vol 35 (10) ◽  
pp. 1065-1072 ◽  
Author(s):  
H. L. Hachiya ◽  
J. L. Carpentier ◽  
G. L. King
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Comparative Studies ◽  
Vascular Endothelial Cells ◽  
Vascular Endothelial ◽  
Insulin Like Growth Factor ◽  
Factor Ii

IGFBP-3 binding to endothelial cells inhibits plasmin and thrombin proteolysis

2002 ◽  
Vol 282 (1) ◽  
pp. E52-E58 ◽  
Author(s):  
B. A. Booth ◽  
M. Boes ◽  
B. L. Dake ◽  
K. L. Knudtson ◽  
R. S. Bar
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Vascular Endothelial Cells ◽  
Binding Protein ◽  
Vascular Endothelial ◽  
Insulin Like Growth Factor ◽  
Heparin Binding ◽  
Binding Region ◽  
Factor Binding ◽  
Igfbp 3

Insulin-like growth factor-binding protein (IGFBP)-3 contains a highly basic COOH-terminal heparin-binding region, the P3 region, which is thought to be important in the binding of IGFBP-3 to endothelial cells. IGFBP-3 and IGFBP-4, and their chimeras IGFBP-34 and IGFBP-43, were treated with plasmin and with thrombin, proteases known to cleave IGFBP-3. IGFBP-3 was highly susceptible to plasmin, whereas IGFBP-4 was less so. Substitution of the P3 region for the P4 region in IGFBP-4 (IGFBP-43) increased the ability of the protease to digest IGFBP-43; substitution of the P4 region for the P3 region in IGFBP-3 (IGFBP-34) decreased the digestion of IGFBP-34. When 125I-labeled IGFBP-3 or125I-IGFBP-43 was first bound to vascular endothelial cells, subsequent proteolysis by either plasmin or thrombin was substantially inhibited. Proteolysis of125I-IGFBP-34 was not inhibited in the presence of endothelial cells. The P3 peptide was cleaved by plasmin but not by thrombin. We conclude that the P3 region is central to proteolysis of IGFBP-3 by plasmin and thrombin, processes which were inhibited by association of IGFBP-3 with endothelial cells.

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