The activation of matriptase requires its noncatalytic domains, serine protease domain, and its cognate inhibitor.
The activation of matriptase requires proteolytic cleavage at a canonical activation motif that converts the enzyme from a one-chain zymogen to an active, two-chain protease. In this study, matriptase bearing a mutation in its catalytic triad was unable to undergo this activational cleavage, suggesting that the activating cleavage occurs via a transactivation mechanism where interaction between matriptase zymogen molecules leads to activation of the protease. Using additional point and deletion mutants, we showed that activation of matriptase requires proteolytic processing at Gly-149 in the SEA domain of the protease, glycosylation of the first CUB domain and the serine protease domain, and intact low density lipoprotein receptor class A domains. Its cognate inhibitor, hepatocyte growth factor activator inhibitor-1, may also participate in the activation of matriptase, based on the observation that matriptase activation did not occur when the protease was co-expressed with hepatocyte growth factor activator inhibitor-1 mutated in its low density lipoprotein receptor class A domain. These results suggest that besides matriptase catalytic activity, matriptase activation requires post-translational modification of the protease, intact noncatalytic domains, and its cognate inhibitor.
Department of Oncology, Lombardi Cancer Center, Georgetown University Medical Center, Washington, D.C. 20057-1412, USA.
Michael D
MD
Oberst
Cicely A
CA
Williams
Robert B
RB
Dickson
Michael D
MD
Johnson
Chen-Yong
CY
Lin
D002460:Cell Line; D004789:Enzyme Activation; D006031:Glycosylation; D006801:Humans; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D053491:Proteinase Inhibitory Proteins, Secretory; D011973:Receptors, LDL / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D015533:Transcriptional Activation; D014357:Trypsin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D008562:Membrane Glycoproteins; D053491:Proteinase Inhibitory Proteins, Secretory; D011973:Receptors, LDL; D011994:Recombinant Proteins; C109149:SPINT1 protein, human; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases; C485595:matriptase; C485596:ST14 protein, human; D014357:Trypsin