Cell-surface processing of pro-ADAMTS9 by furin.
Processing of polypeptide precursors by proprotein convertases (PCs) such as furin typically occurs within the trans-Golgi network. Here, we show in a variety of cell types that the propeptide of ADAMTS9 is not excised intracellularly. Pulse-chase analysis in HEK293F cells indicated that the intact zymogen was secreted to the cell surface and was subsequently processed there before release into the medium. The processing occurred via a furin-dependent mechanism as shown using PC inhibitors, lack of processing in furin-deficient cells, and rescue by furin in these cells. Moreover, down-regulation of furin by small interference RNA reduced ADAMTS9 processing in HEK293F cells. PC5A could also process pro-ADAMTS9, but similarly to furin, processed forms were absent intracellularly. Cell-surface, furin-dependent processing of pro-ADAMTS9 creates a precedent for extracellular maturation of endogenously produced secreted proproteins. It also indicates the existence of a variety of mechanisms for processing of ADAMTS proteases.
Koo
Bon-Hun
BH
Department of Biomedical Engineering and Orthopaedic Research Center, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Longpré
Jean-Michel
JM
Somerville
Robert P T
RP
Alexander
J Preston
JP
Leduc
Richard
R
Apte
Suneel S
SS
D051722:ADAM Proteins / Q000378:metabolism*; D000071119:ADAMTS9 Protein; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism*; D002522:Chlorocebus aethiops; D006224:Cricetinae; D045683:Furin / Q000737:chemistry*; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D012697:Serine Endopeptidases / Q000378:metabolism
D012697:Serine Endopeptidases; D045683:Furin; D051722:ADAM Proteins; D000071119:ADAMTS9 Protein; C412869:ADAMTS9 protein, human