Zymogen activation and subcellular activity of subtilisin kexin isozyme 1/site 1 protease.
The proprotein convertase subtilisin kexin isozyme 1 (SKI-1)/site 1 protease (S1P) plays crucial roles in cellular homeostatic functions and is hijacked by pathogenic viruses for the processing of their envelope glycoproteins. Zymogen activation of SKI-1/S1P involves sequential autocatalytic processing of its N-terminal prodomain at sites B'/B followed by the herein newly identified C'/C sites. We found that SKI-1/S1P autoprocessing results in intermediates whose catalytic domain remains associated with prodomain fragments of different lengths. In contrast to other zymogen proprotein convertases, all incompletely matured intermediates of SKI-1/S1P showed full catalytic activity toward cellular substrates, whereas optimal cleavage of viral glycoproteins depended on B'/B processing. Incompletely matured forms of SKI-1/S1P further process cellular and viral substrates in distinct subcellular compartments. Using a cell-based sensor for SKI-1/S1P activity, we found that 9 amino acid residues at the cleavage site (P1-P8) and P1' are necessary and sufficient to define the subcellular location of processing and to determine to what extent processing of a substrate depends on SKI-1/S1P maturation. In sum, our study reveals novel and unexpected features of SKI-1/S1P zymogen activation and subcellular specificity of activity toward cellular and pathogen-derived substrates.
From the Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland.
Joel Ramos
JR
da Palma
From the Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland.
Dominique Julien
DJ
Burri
From the Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland.
Joël
J
Oppliger
the Department of Biology and.
Marco
M
Salamina
the Department of Biology and.
Laura
L
Cendron
the Department of Pharmaceutical Sciences, Centro Ricerche Interdipartimentale Biotecnologie Innovative, University of Padua, 35121 Padua, Italy, and.
Patrizia Polverino
PP
de Laureto
the Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, University of Montreal, Montreal, Quebec H2W 1R7, Canada.
Nabil Georges
NG
Seidah
From the Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland, Stefan.Kunz@chuv.ch.
Stefan
S
Kunz
From the Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland, Antonella.Pasquato@chuv.ch.
Antonella
A
Pasquato
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D003412:Cricetulus; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000737:chemistry* / Q000378:metabolism; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D043484:Proprotein Convertases / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D059748:Proteolysis; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000378:metabolism
D004792:Enzyme Precursors; D014759:Viral Envelope Proteins; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; C115575:membrane-bound transcription factor peptidase, site 1
Bioluminescence; Biosensor; Enzyme Mechanism; Enzyme Processing; Serine Protease