Amphiphysin IIb-1, a novel splicing variant of amphiphysin II, regulates p73beta function through protein-protein interactions.

p73 is a nuclear protein that is similar in structure and function to p53. Notably, the C-terminal region of p73 has a regulatory function, through interactions with a positive or negative regulator. In this study, we use the yeast two-hybrid technique to identify a novel p73beta binding protein, designated amphiphysin ...
IIb-1. Amphiphysin IIb-1 is one of the splicing variants of amphiphysin II, and has a shorter protein product than amphiphysin IIb, which has been previously reported. We confirmed that amphiphysin IIb-1 binds full-length p73beta, both in vitro and in vivo. This association is mediated via the SH3 domain of amphiphysin IIb-1 and C-terminal amino acids 321-376 of p73beta. Double immunofluorescence patterns revealed that p73beta is relocalized to the cytoplasm in the presence of amphiphysin IIb-1. Overexpression of amphiphysin IIb-1 was found to significantly inhibit the transcriptional activity of p73beta in a dose-dependent manner. In addition, the cell death function of p73beta was inhibited by amphiphysin IIb-1. These findings offer a new insight into the regulation mechanism of p73beta, and suggest that amphiphysin IIb-1 modulates p73beta function by direct binding.
Mesh Terms:
Alternative Splicing, Amino Acid Sequence, Animals, Base Sequence, COS Cells, Cell Death, Cytoplasm, DNA-Binding Proteins, Dose-Response Relationship, Drug, Genes, Tumor Suppressor, Luciferases, Microscopy, Fluorescence, Models, Genetic, Molecular Sequence Data, Nerve Tissue Proteins, Nuclear Proteins, Plasmids, Point Mutation, Protein Binding, Protein Structure, Tertiary, Transcription, Genetic, Tumor Suppressor Proteins, Two-Hybrid System Techniques
Oncogene
Date: Oct. 11, 2001
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