Mouse matriptase-2: identification, characterization and comparative mRNA expression analysis with mouse hepsin in adult and embryonic tissues

Abstract

We report the identification and characterization of mouse matriptase-2 (m-matriptase-2), an 811-amino-acid protein composed of an N-terminal cytoplasmic domain, a membrane-spanning domain, two CUB (complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domains, three LDLR (low-density-lipoprotein receptor class A) domains and a C-terminal serine-protease domain. All m-matriptase-2 protein domain boundaries corresponded with intron/exon junctions of the encoding gene, which spans approx. 29 kb and comprises 18 exons. Matriptase-2 is highly conserved in human, mouse and rat, with the rat matriptase-2 gene ( r-maltriptase-2 ) predicted to encode transmembrane and soluble isoforms. Western-blot analysis indicated that m-matriptase-2 migrates close to its theoretical molecular mass of 91 kDa, and immunofluorescence analysis was consistent with the proposed surface membrane localization of this protein. Reverse-transcription PCR and in-situ -hybridization analysis indicated that m-matriptase-2 expression overlaps with the distribution of mouse hepsin (m-hepsin, a cell-surface serine protease identified in hepatoma cells) in adult tissues and during embryonic development. In adult tissues both are expressed at highest levels in liver, kidney and uterus. During embryogenesis m-matriptase-2 expression peaked between days 12.5 and 15.5. m-hepsin expression was biphasic, with peaks at day 7.5 to 8.5 and again between days 12.5 and 15.5. In situ hybridization of embryonic tissues indicated abundant expression of both m-matriptase-2 and m-hepsin in the developing liver and at lower levels in developing pharyngo-tympanic tubes. While m-hepsin was detected in the residual embryonic yolk sac and with lower intensity in lung, heart, gastrointestinal tract, developing kidney tubules and epithelium of the oral cavity, m-matriptase-2 was absent in these tissues, but strongly expressed within the nasal cavity by olfactory epithelial cells. Mechanistic insight into the potential role of this new transmembrane serine protease is provided by its novel expression profile in embryonic and adult mouse.

Human Polyserase-2, a Novel Enzyme with Three Tandem Serine Protease Domains in a Single Polypeptide Chain

“…These data also indicate a preference of polyserase-2 for substrates with an Arg instead of Lys in position P1 (Fig. 5A), as described previously for other related proteins such as pancreasin (21) or matriptase-2 (23,24). The activity of both recombinant proteins was substantially abolished with the serine proteinase inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride, but not with EDTA or E-64, thereby providing additional evidence for their classification as serine proteases.…”

“…Thus, the first domain shows the highest percentage of identity with ␥1-tryptase (42%) (20), pancreasin (42%) (21), different members of the type II transmembrane serine proteinase family such as matriptase (40%) and matriptase-2 (40%) (22)(23)(24), and the three serine protease domains of polyserase-1 (41%) (10). The second domain is most closely related to matriptase-2 (33% identities), prostasin (30%) (25), ⑀-tryptases (29%) (26), and the three serine protease domains of polyserase-1 (29%) (10).…”

Matriptase inhibition by hepatocyte growth factor activator inhibitor-1 is essential for placental development

“…epidermis and oral epithelium) and the embryonic matriptase expression will be evolutionarily conserved despite providing no benefit. Alternatively, matriptase has a critical function in development, but this function is redundant with closely related proteases such as matriptase-2 (Velasco et al, 2002;Hooper et al, 2003) and matriptase-3 . Finally, embryonic matriptase expression may be important for development only under environmental stress conditions (infection, intoxication, malnutrition, heat/cold exposure, other) that do not present under standard animal housing conditions.…”

Proteolytic Activation of Pro-Macrophage-Stimulating Protein by Hepsin

“…In this report, we detected a strong correlation of MSP expression with hepsin expression in the liver, kidney, and pancreas that was superior to the corresponding correlations observed between MSP and HGFA or MSP and MT-SP1. Both hepsin and MSP are produced by hepatocytes in the liver (58,59) and renal tubule cells in the kidney (58,60), which were recently shown to increase MSP production during the regenerative phase in a mouse renal injury model (60). In light of the potent pro-MSP convertase activity for hepsin in vitro, the coexpression results suggest that hepsin may regulate pro-MSP activation in tissue homeostasis or after tissue injury.…”