1994 Fiscal Year Final Research Report Summary
Significance of protein tyrosine phosphatase in the Kidney
| Project/Area Number |
05454342
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Kidney internal medicine
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| Research Institution | Osaka University |
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Principal Investigator |
UEDA Naohiko Osaka Univ.Med.Sch.Lecturer, 医学部, 講師 (70115997)
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| Co-Investigator(Kenkyū-buntansha) |
MORIYAMA Toshiki Osaka Univ.Hospital.Clinical fellow, 医学部・附属病院, 医員
IMAI Enyu Osaka Univ.Med.Sch.Assistant proffesor., 医学部, 助手 (00223305)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Protein Tyrosine phosphatase / Protein Tyrosine phosphorylation / cDNA cloning / Nephron segment / Recombinant protein |
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| Research Abstract |
The aim of this research project was to elucidate the physiological and pathophysiological significance of protein tyrosine phosphatase (PTPase) in the kidney. As a first approach towards this goal, we conducted cDNA cloning of PTPases from rat kidney. We obtained two PTPase cDNAs ; one is a transmembrane type PTPase which was turned out to be a counterpart of mouse LRP,and the other is a novel cytosolic PTPase, which was designated as RKPTP.Since heterogeneity is an important characteristics of the kidney, knowledge about the intrarental distribution is helpful to understand the function of the particlar gene in the kidney. So, we tried to reveal the intrarental distribution of LRP mRNA in the rat kidney using microdissection-reversetranscription-polymerase chain reaction method (RT-PCR), Northern blotting, and immunohistochemistry. RT-PCR revealed the LRPmRNA expression along the nephron segments with the rank of order as IMCD>PCT>CCD>MTAL=Glm. This pattern of expression was confirmed by immunostaining of the rat kidney using anti-LRP polyclonal antibody. These results give an insight into the possible involvement of LRP in the function of IMCD such as urinaty concentrating mechanism. Regarding the novel cytosolic PTP(RKPTP), we demonstrated its PTPase activity using GST-RKPTP fusion protein expressed in the bacterial system. Northern blotting revealed RKPTP tissue distribution (kidney>lung>spleen>brain>liver). Southern blotting using rat genomic DNA suggested that there is a single copy of RKPTP gene per rat haploid genome. Further analyzes are being performed in terms of the significance of RKPTP in the physiological and pathophysiological processes of the kidney such as glomeulonephritis.
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