| Project/Area Number |
09660099
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
応用微生物学・応用生物化学
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| Research Institution | Miyazaki University |
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Principal Investigator |
SUIKO Masahito Miyazaki University, Department of Biological Resource Sciences, Professor, 農学部, 教授 (00128357)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAKIBARA Yoichi Miyazaki Unviersity, Department of Biological Resource Sciences, Assistant Profe, 農学部, 助手 (90295197)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Tyrosine Sulfation / Post-translational Modification / Sulfotransferase / Golgi Body / Sorting / Microsome / Complement C3 / Fibronectin |
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| Research Abstract |
Post-translational protein modification by tyrosine sulfation is now known to have a widespread occurrence among proteins of multicellular eukaiyotic organisms. I view of that the vast majority of tyrosine-sulfated (TyrS) proteins identified are secretory proteins and that the tyrosyiprotein sulfotransferase (TPST), which catalyzes the protein tyrosine sulfation reaction, is located in the Golgi, the initial speculation on the functional relevance of this unique protein modification was focused on the aspect of protein secretion. A hypothetical role of tyrosine sulfation in the packaging of secretory proteins into secretory granules was further elaborated. Along the same line, we have been investigating the presence of a putative TyrS receptor involved in mediating the targeting and/or intracellular transport of tyrosine-sulfated proteins. By employing the affinity gel fraction technique, we have detected a 175 kDa tyrosine-O-.sulfate-binding protein in sodium choleate etracts of the m
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icrosomal membrane fractions of bovine liver and pancreas, as well as canine liver and pancreas. Western blot analysis revealed the presence of the bovine liver TyrS-binding protein in complexes with tyrosine-sulfated proteins both 1.in vivo and in vitro, suggesting the putative role of the former being the receptor for the latter. A hypothetical model for TyrS residues serving as an apical targeting signal during the biosynthetic transport of tyrosine-sulfated proteins, as mediated by the TyrS receptor, in MDCK cells is proposed. TyrS proteins are recognized and bound by the TyrS receptor, and packaged into the transport vesicle budded off from the trans Golgi membrane compartment. The transport vesicle fuses with a CURL-like membrane compartment in which tyrosine-sulfated proteins become dissociated from the TyrS receptor due to the low pH environment presumably generated through the action of ATPase/H+ pump. The vesicle carrying free TyrS proteins buds off from the CURl-like membrane compartment and migrates toward the apical domain of the plasma membrane. Upon fusion with the apical plasma membrane, tyrosine-sulfated proteins become secreted from the apical surface. Less
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