PQBP-1/Npw38, a nuclear protein binding to the polyglutamine tract, interacts with U5-15kD/dim1p via the
M Waragai1, E Junn, M Kajikawa
1Department of Neurology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
Abstract:
PQBP-1 was identified as a binding protein to the polyglutamine tract present in various transcription-related factors and causative genes for neurodegenerative disorders. This novel gene contains at least two functional domains, WW domain and carboxyl-terminal domain (CTD), strictly conserved beyond species. Although human PQBP-1 additionally contains the polar amino acid-rich domain by which it binds to the polyglutamine tract, genuine physiological function(s) have not been clarified. In this study, we showed that U5-15kD, human homologue of fission yeast dim1p, is a partner molecule of PQBP-1 binding to CTD. This finding suggests physiological functions of PQBP-1 in splicing, cell cycle, and ubiquitination, through which we can speculate the pathological roles of PQBP-1 in triplet repeat diseases.
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