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Polyglutamine tract-binding protein-1 binds to U5-15kD via a continuous 23-residue segment of the C-terminal domain
Masaki Takahashi1, Mineyuki Mizuguchi, Hiroyuki Shinoda
1Faculty of Pharmaceutical Sciences, University of Toyama, 2630, Sugitani, Toyama 930-0194, Japan.
Abstract:
Polyglutamine tract-binding protein-1 (PQBP-1) is a nuclear protein that interacts with various proteins, including RNA polymerase II and the spliceosomal protein U5-15kD. PQBP-1 is known to be associated with X-linked mental retardation in which a frameshift mutation in the PQBP-1 gene occurs. In the present study, we demonstrate that PQBP-1 binds to U5-15kD via a continuous 23-residue segment within its C-terminal domain. Intriguingly, this segment is lost in the frameshift mutants of PQBP-1 associated with X-linked mental retardation. These findings suggest that the frameshift mutations in the PQBP-1 gene lead to expression of mutants lacking the ability to interact with U5-15kD.
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