Spinesin/TMPRSS5, a novel transmembrane serine protease, cloned from human spinal cord.
A cDNA encoding a novel serine protease, which we designated spinesin, has been cloned from human spinal cord. The longest open reading frame was 457 amino acids. A homology search revealed that the human spinesin gene was located at chromosome 11q23 and contained 13 exons, the gene structure being similar to that of TMPRSS3 whose gene is also located on 11q23. Spinesin has a simple type II transmembrane structure, consisting of, from the N terminus, a short cytoplasmic domain, a transmembrane domain, a stem region containing a scavenger receptor-like domain, and a serine protease domain. Unlike TMPRSS3, it carries no low density lipoprotein receptor domain in the stem region. The extracellular region carries five N-glycosylation sites. The sequence of the protease domain carried the essential triad His, Asp, and Ser and showed some similarity to that of TMPRSS2, hepsin, HAT, MT-SP1, TMPRSS3, and corin, sharing 45.5, 41.9, 41.3, 40.3, 39.1, and 38.5% identity, respectively. The putative mature protease domain preceded by H(6)DDDDK was produced in Escherichia coli, purified, and successfully activated by immobilized enterokinase. Its optimal pH was about 10. It cleaved synthetic substrates for trypsin, which is inhibited by p-amidinophenylmethanesulfonyl fluoride hydrochloride but not by antipain or leupeptin. Northern blot analysis against mRNA from human tissues including liver, lung, placenta, and heart demonstrated a specific expression of spinesin mRNA in the brain. Immunohistochemically, spinesin was predominantly expressed in neurons, in their axons, and at the synapses of motoneurons in the spinal cord. In addition, some oligodendrocytes were clearly stained. These results indicate that spinesin is transported to the synapses through the axons after its synthesis in the cytoplasm and may play important roles at the synapses. Further analyses are required to clarify its roles at the synapses and in oligodendrocytes.
Yamaguchi
Nozomi
N
Department of Cell Biology, Research Institute for Neurological Diseases and Geriatrics, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan. nozomi@koto.kpu-m.ac.jp
Okui
Akira
A
Yamada
Tatsuo
T
Nakazato
Hiroshi
H
Mitsui
Shinichi
S
D000368:Aged; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D001419:Bacteria / Q000378:metabolism; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002874:Chromosome Mapping; D002880:Chromosomes, Human, Pair 11; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005091:Exons; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics*; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D016366:Open Reading Frames; D009924:Organ Culture Techniques; D011480:Protease Inhibitors / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014105:Tosyl Compounds / Q000494:pharmacology; D014357:Trypsin / Q000737:chemistry
D000596:Amino Acids; D018076:DNA, Complementary; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D009363:Neoplasm Proteins; D011480:Protease Inhibitors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014105:Tosyl Compounds; C003614:4-toluenesulfonyl fluoride; D012697:Serine Endopeptidases; C421305:TMPRSS2 protein, human; C409042:TMPRSS3 protein, human; C450831:TMPRSS5 protein, human; D014357:Trypsin