2002 Fiscal Year Final Research Report Summary
Increased expression and secretion of r-Gsp protein, rat counterpart of complement C1s precursor during differentiation in rat C6 glioma cells
| Project/Area Number |
13671429
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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 |
Cerebral neurosurgery
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| Research Institution | GIFU UNIVERSITY |
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Principal Investigator |
SHINODA Jun Department School of Medicine, Assistant Professor, 医学部, 助教授 (50273131)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Noboru Department School of Medicine, Professor, 医学部, 教授 (10021487)
YOSHIMURA Shin-ichi Department School of Medicine, Assistant, 医学部, 助手 (40240353)
KAKU Yasuhiko Department University Hospital, Associate Professor, 医学部附属病院, 講師 (90242718)
NAKAJIMA Shigeru Department School of Medicine, Professor, 医学部, 教授 (60188935)
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| Project Period (FY) |
2001 – 2002
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| Keywords | C6 glioma cells / glial differentiation / cAMP / serine protease / S100 protein / complement C1s |
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| Research Abstract |
The gene, termed r-gsp, was originally isolated during identification of differentiation-associated molecules in rat C6 glial cells. Its mRNA expression was markedly increased during cAMP-induced glial cell differentiation. The deduced amino acid sequence of r-gsp was homologous to those of complement C1s precursors of hamsters and humans. In the present study, we raised anti-peptide antibody against r-Gsp protein and analyzed its change during cAMP-induced differentiation. The 90 kDa r-Gsp protein increased time-dependently and reached the maximal level (〜7.6-fold increase ) at 24 h in response to dibutyryl cyclic AMP (dbcAMP) and theophylline. Moreover, it was secreted into the medium and then was cleaved to form disulfide-linked fragments, one of which was 30 kDa, similar to C1s, suggesting its processing in the extracellular space. In fact, the partially purified r-Gsp from culture medium was cleaved by active human C1r to form a 30 kDa polypeptide. Moreover, secreted r-Gsp protein cleaved human C4a to yield C4a' and associated with human serum C1-esterase inhibitor, strongly suggesting that r-Gsp protein is rat C1s. However, in C6 cells overexpressing r-Gsp, their morphology and proliferation rate were similar to those in parent C6 cells. These results suggest that r-Gsp protein could not induce glial differentiation alone, and suggest that r-Gsp protein was secreted as a proenzyme and processed in culture medium.
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