1996 Fiscal Year Final Research Report Summary
Functional Molecules on Glomerular Epithelial Cells
| Project/Area Number |
08044260
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Niigata Univeisity |
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Principal Investigator |
SHIMIZU Fujio Niigata Unlv.Sch.Med., Professor, 医学部, 教授 (40012728)
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| Co-Investigator(Kenkyū-buntansha) |
KAWACHI Hiroshi Niigata Unly.Sch.Med., Assoclate Professor, 医学部, 助教授 (60242400)
MORIOKA Tetsuo Niigata Unlv.Sch.Med.Associate Professor, 医学部, 助教授 (00210146)
SHIA Michael A Boston Unlv.Sch.Med., Associate Professor, 医学部, 助教授
SALANT David J Boston Unlv.Sch.Med.Professor, 医学部, 教授
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| Project Period (FY) |
1996
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| Keywords | p51 / ZO-1 / proteinuria / slit membrane / tyrosine phosphorylation / glomerular permeability / monoclonal antibody |
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| Research Abstract |
cDNA library was prepar from one day old rat glomeruli, because the metabolic labeling by ^<35>S-methyonine revealed that mAb 5-1-6 recognized antigen (p51) was more actively synthesized in one day old rat kidney than in 5 days old or matured rat kidneys. cDNA cloning by mAb 5-1-6 is being still continued using this library and COS cells for expression. However we have not yet succeeded in identifying p51.
On the other hand the precise localization of p51 was further investigated with immunoelectron microscopy by counting the gold particles. The number of gold particles at the base of foot processes of podocytes is 0.77 particles/mm length of glomerular basement membrane. of particles at the lateral surface and at intermittent space of foot processes are 1.61 and 2.14, respectively.From these results we concluded that p51 is mainly localized at the slit diaphragm and its cytoplasmic face and that p51 is a component of slit diaphragin.
To clarify the mechanisms of abnormal proteinuria induced by mAb 5-1-6, we have investigated the molecular nature of slit diaphragm. Any morphological alterations of the structure of slit diaphragm was not detected with electron microscopy in proteinuric rats induced by mAb 5-1-6. However, p51 and ZO-1, tight junction protein, staining were definitely decreased at glomeruii of rats 5 days after mAb injection when abnomal proteinuria reached a peak value. lmmunoblot analysis also showed that intensity of ZO-1 band was decreased at glomeruii of 5 days after mAb injection. From these results we conchuded that p51 is an associate protein of ZO-1 and that these proteins are not necessary for maintaining the structure of slit diaphragm but necessary for maintaining the barrier function of slit diaphragm.
We have further investigated whether tyrosine phosphorylation plays a role for this molecular rearrangement of p51 and ZO-1. Tyrosine phosphorylation was not detected at any time points after mAb 5-1-6 injection.
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