1992 Fiscal Year Final Research Report Summary
Analysis of the third cytosol factor involving in the neutrophil NADPH oxidase
| Project/Area Number |
03671086
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
医学一般
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| Research Institution | Kumamoto University |
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Principal Investigator |
NUNOI Hiroyuki Kumamoto University Medical School, Department of Pediatrics, assistant professo, 医学部, 助手 (50218260)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Chronic Granulomatous Disease (CGD) / NADPH oxidase / Small G Protein (rac1 / 2) / p47-phox / p67-phox |
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| Research Abstract |
Chronic Granulomatous Disease (CGD) is an inherited condition rendering neutrophils incapable of killing invading pathogens. The neutrophils from the patients with CGD fail to produce the superoxide. This terminal superoxide generating enzyme (NADPH oxidase) had been found to be consisted of the following 5 components ; gp91 phagocyte oxidase(phox) and p22-phox (membrane-bound heterodimer proteins of cytochrome b558) and p47-phox, p67-phox and the unknown third cytsol factor.
By the collaboration with professor Takai in Kobe University, we identified this third cytosol factor as one of the family of small G proteins (rac1 or 2). We also found NADPH oxidase system was regulated by the stimulatory and inhibitory GDP/GTP exchange proteins for racp21s (smgGDS and rho GDI) and the posttranslational processing of racp21s is important not only for their interaction with regulatory proteins but also for their NADPH oxidase activation.
In addition, we report the molecular analysis of five CGD patients with the p67-phox deficiency. The RNAs were prepared from EB virus transformed B cell lines from the patients who had not any anti-p67 antibody reactive protein in the B cell cytosol. Protein coding sequences of p67-phox cDNA were analyzed by the direct sequence method using RT-PCR amplified cDNA. One of the patients, dinucleotides(AG) insertion at the position of 423 nucleotide residue was found. In another patient, 186 nucleotide residues from 694 to 879 residues were deleted. By this large deletion, most of src homology locus 3 (SH3) which was thought to be important for interacting with small G protein was truncated. In the other 3 patients, two other point mutations at the 566 and 1007 residues were found. However, the relationships of the mutation and the occurrence of CGD has not been established yet.
By these analysis, we have been revealing the genetic background of CGD patients in Japan.
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