beta-catenin forms protein aggregation at high concentrations in hek293tcells

background: the canonical wnt signal transduction (or the wnt/β-catenin pathway) plays a crucial role in the development of animals and in carcinogenesis. beta-catenin is the central component of this signaling pathway. the activation of wnt/β-catenin signaling results in the cytoplasmic and nuclear accumulation of β-catenin. in the nucleus, β-catenin interacts with the tcf/lef transcription factors and, therefore, participates in the upregulation or downregulation of some important genes involved in diverse cellular activities. in addition, β-catenin is a critical component of the cadherin-mediated cell adherens junction. we had previously noticed that very high cellular concentrations of β-catenin had a negative effect on the transcriptional activity of this protein and, therefore, the aim of this study was to find a mechanism for this negative interaction. methods: cell fractionation, western blotting, and immunofluorescence microscopy experiments were performed to measure β-catenin protein levels and β-catenin cellular localization in hek293tcells transfected with various amounts of a β-catenin-encoding plasmid. also, total rna was extracted from the cells and used for reverse transcriptase-pcr experiments to measure the expression of the β-catenin target genes. spss, version 16, was used to analyze the results statistically. results: we demonstrated that overexpression of β-catenin led to the formation of rod-shaped protein aggregates. the aggregate structures were mainly formed in the cell nucleus and were heavy enough to be isolated by centrifugation. beta-catenin aggregate formation was accompanied by a decrease in the expression of theβ-catenin target genes used in this study. conclusion: since deregulation of β-catenin function occurs in several human diseases, including cancer and neurological disorders, the results of this paper further support the possible biological and clinical significance of β-catenin aggregate formation.