title: The protease inhibitor HAI-2, but not HAI-1, regulates matriptase activation and shedding through prostasin.
abstract: The membrane-anchored serine proteases, matriptase and prostasin, and the membrane-anchored serine protease inhibitors, hepatocyte growth factor activator inhibitor (HAI)-1 and HAI-2, are critical effectors of epithelial development and postnatal epithelial homeostasis. Matriptase and prostasin form a reciprocal zymogen activation complex that results in the formation of active matriptase and prostasin that are targets for inhibition by HAI-1 and HAI-2. Conflicting data, however, have accumulated as to the existence of auxiliary functions for both HAI-1 and HAI-2 in regulating the intracellular trafficking and activation of matriptase. In this study, we, therefore, used genetically engineered mice to determine the effect of ablation of endogenous HAI-1 and endogenous HAI-2 on endogenous matriptase expression, subcellular localization, and activation in polarized intestinal epithelial cells. Whereas ablation of HAI-1 did not affect matriptase in epithelial cells of the small or large intestine, ablation of HAI-2 resulted in the loss of matriptase from both tissues. Gene silencing studies in intestinal Caco-2 cell monolayers revealed that this loss of cell-associated matriptase was mechanistically linked to accelerated activation and shedding of the protease caused by loss of prostasin regulation by HAI-2. Taken together, these data indicate that HAI-1 regulates the activity of activated matriptase, whereas HAI-2 has an essential role in regulating prostasin-dependent matriptase zymogen activation.
authors: From the Proteases and Tissue Remodeling Section, Oral and Pharyngeal Cancer Branch, and the Department of Cellular and Molecular Medicine, Faculty of Health Science, University of Copenhagen, 2200 Copenhagen N, Denmark.
authors: Stine
authors: S
authors: Friis
authors: From the Proteases and Tissue Remodeling Section, Oral and Pharyngeal Cancer Branch, and Clinical Research Core, NIDCR, National Institutes of Health, Bethesda, Maryland 20892.
authors: Katiuchia Uzzun
authors: KU
authors: Sales
authors: From the Proteases and Tissue Remodeling Section, Oral and Pharyngeal Cancer Branch, and the College of Medicine, The Ohio State University, Columbus, Ohio 43210, and.
authors: Jeffrey Martin
authors: JM
authors: Schafer
authors: the Department of Cellular and Molecular Medicine, Faculty of Health Science, University of Copenhagen, 2200 Copenhagen N, Denmark.
authors: Lotte K
authors: LK
authors: Vogel
authors: the Section of Oncopathology and Regenerative Biology, Department of Pathology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
authors: Hiroaki
authors: H
authors: Kataoka
authors: From the Proteases and Tissue Remodeling Section, Oral and Pharyngeal Cancer Branch, and thomas.bugge@nih.gov.
authors: Thomas H
authors: TH
authors: Bugge
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D004789:Enzyme Activation; D020868:Gene Silencing; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D053491:Proteinase Inhibitory Proteins, Secretory / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000378:metabolism; D000099271:Prostasin
chemical_list: D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D053491:Proteinase Inhibitory Proteins, Secretory; D034741:RNA, Small Interfering; D012697:Serine Endopeptidases; D015842:Serine Proteinase Inhibitors; D000099271:Prostasin; C109149:SPINT1 protein, human; C109148:SPINT2 protein, human; C504591:Spint1 protein, mouse; C533525:Spint2 protein, mouse; C485595:matriptase
keywords: Cellular Transport; Enzyme Catalysis; Enzyme Mechanism; Epithelium; Protease Inhibitor; Serine Protease; Zymogen Activation