| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
In this project, I have tried to clarify how a TPA-responsible PKC, nPKCη, is involved in the junctional development during epithelial cell polarization, especially, in the light of the correlation with TPA-unresponsible PKCs, aPKCs which we had shown to play critical role in the process. Essentially, we utilized a dominant negative mutant of nPKCη (n OKCηkn) to specifically suppress the activity of nPKCη during a calcium switch-induced junctional formation or TPA-induced tight junction (TJ)-like structure formation.
nPKCηkn-overexpressed MDCK cells failed to restore TJs as well as adherents junctions (Ajs) after a calcium switch. These cells also showed reduced cell-cell adhesion, and impaired cortical F-actin bundle, suggesting that nPKCη is important for the initial adherens junction formation. Together with our finding that nPKCηkn as well as aPKCkn suppressed TPA-induced TJ-like formation, these results suggest that a PKCs work downstream of nPKCη. Interestingly, TPA treatment induced a transient accumulation of E-cadherin at cell-cell contact region formed between extensions of neighboring cells. Therefore, nPKCη might mediate initial cell-cell contact signals through E-cadherin to E-cadherin clustering to develop stable adherens junctions that are lined with F-actin cortical bundles.
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