Cleavage of von Willebrand factor requires the spacer domain of the metalloprotease ADAMTS13.
ADAMTS13 consists of a reprolysin-type metalloprotease domain followed by a disintegrin domain, a thrombospondin type 1 motif (TSP1), Cys-rich and spacer domains, seven more TSP1 motifs, and two CUB domains. ADAMTS13 limits platelet accumulation in microvascular thrombi by cleaving the Tyr1605-Met1606 bond in von Willebrand factor, and ADAMTS13 deficiency causes a lethal syndrome, thrombotic thrombocytopenic purpura. ADAMTS13 domains required for substrate recognition were localized by the characterization of recombinant deletion mutants. Constructs with C-terminal His6 and V5 epitopes were expressed by transient transfection of COS-7 cells or in a baculovirus system. No association with extracellular matrix or cell surface was detected for any ADAMTS13 variant by immunofluorescence microscopy or chemical modification. Both plasma and recombinant full-length ADAMTS13 cleaved von Willebrand factor subunits into two fragments of 176 kDa and 140 kDa. Recombinant ADAMTS13 was divalent metal ion-dependent and was inhibited by IgG from a patient with idiopathic thrombotic thrombocytopenic purpura. ADAMTS13 that was truncated after the metalloprotease domain, the disintegrin domain, the first TSP1 repeat, or the Cys-rich domain was not able to cleave von Willebrand factor, whereas addition of the spacer region restored protease activity. Therefore, the spacer region is necessary for normal ADAMTS13 activity toward von Willebrand factor, and the more C-terminal TSP1 and CUB domains are dispensable in vitro.
Zheng
Xinglong
X
Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Nishio
Kenji
K
Majerus
Elaine M
EM
Sadler
J Evan
JE
D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D020816:Amino Acid Motifs; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D019921:Biotinylation; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003545:Cysteine / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D005109:Extracellular Matrix / Q000378:metabolism; D017353:Gene Deletion; D005822:Genetic Vectors; D006801:Humans; D007313:Insecta; D008666:Metalloendopeptidases / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000737:chemistry; D014841:von Willebrand Factor / Q000737:chemistry / Q000378:metabolism*
D018076:DNA, Complementary; D000939:Epitopes; D011994:Recombinant Proteins; D014841:von Willebrand Factor; D014443:Tyrosine; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D003545:Cysteine