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[摘要]：The bHLH transcription factor E2A controls proliferation and differentiation in many cell types including kidney epithelial cells. To identify regulatory binding partners of E2A in the kidney, a yeast two-hybrid assay with a human adult kidney cDNA library was performed. Results demonstrated E2A interactions with other HLH proteins including IdI-3 and Pod1 and the Na/K-ATPase beta 1 subunit. The specificity of beta 1 subunit binding was confirmed by co-immunoprecipitation of E2A and beta 1 subunit deletion constructs in HEK cells demonstrating E2A binding to the cytoplasmic tail of the beta 1 subunit. Immunofluorescence and Western analysis of HEK cells co-transfected with GFP-beta 1 Subunit and E2A demonstrated E2A membrane binding and increased PI subunit membrane localization. Increased PI subunit expression resulted in decreased nuclear E2A expression and protein half-life and reduced E2A induced gene expression. These results suggest that E2A and Na/K-ATPase beta 1 subunit expression in epithelial cells are regulated by interactions between these proteins. (C) 2008 Elsevier Inc. All rights reserved. |
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