Neurobin/TMPRSS11c, a novel type II transmembrane serine protease that cleaves fibroblast growth factor-2 in vitro.
TTSPs [type II TMPRSSs (transmembrane serine proteases)] are a growing family of trypsin-like enzymes with, in some cases, restricted tissue distribution. To investigate the expression of TTSPs in the nervous system, we performed a PCR-based screening approach with P10 (postnatal day 10) mouse spinal cord mRNA. We detected the expression of five known TTSPs and identified a novel TTSP, which we designated neurobin. Neurobin consists of 431 amino acids. In the extracellular part, neurobin contains a single SEA (sea-urchin sperm protein, enterokinase and agrin) domain and a C-terminal serine protease domain. RT-PCR (reverse transcription-PCR) analysis indicated the expression of neurobin in spinal cord and cerebellum. Histochemical analysis of brain sections revealed distinct staining of Purkinje neurons of the cerebellum. Transiently overexpressed neurobin was autocatalytically processed and inserted into the plasma membrane. Autocatalytic activation could be suppressed by mutating Ser(381) in the catalytic pocket to an alanine residue. The protease domain of neurobin, produced in Escherichia coli and refolded from inclusion bodies, cleaved chromogenic peptides with an arginine residue in position P(1). Serine protease inhibitors effectively suppressed the proteolytic activity of recombinant neurobin. Ca2+ or Na+ ions did not significantly modulate the catalytic activity of the protease. Recombinant neurobin processed 17-kDa FGF-2 (fibroblast growth factor-2) at several P(1) lysine and arginine positions to distinct fragments, in a heparin-inhibitable manner, but did not cleave FGF-7, laminin or fibronectin. These results indicate that neurobin is an authentic TTSP with trypsin-like activity and is able to process FGF-2 in vitro.
Stallmach
Robert
R
Department of Biochemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland.
Gloor
Sergio M
SM
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009420:Nervous System / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution; D014162:Transfection
D008565:Membrane Proteins; D016222:Fibroblast Growth Factor 2; D012697:Serine Endopeptidases; C528996:neurobin protein, mouse