National Center for
4CB9: Structure Of Full-length Ctnnbl1 In P43212 Space Group
Structural and mutational analysis reveals that CTNNBL1 binds NLSs in a manner distinct from that of its closest armadillo-relative, karyopherin alpha
FEBS Lett. (2014) 588 p.21-27
CTNNBL1 is a spliceosome-associated protein that binds nuclear localization signals (NLSs) in splice factors CDC5L and Prp31 as well as the antibody diversifying enzyme AID. Here, crystal structures of human CTNNBL1 reveal a distinct structure from its closest homologue karyopherin-alpha. CTNNBL1 comprises a HEAT-like domain (including a nuclear export signal), a central armadillo domain, and a coiled-coil C-terminal domain. Structure-guided mutations of the region homologous to the karyopherin-alpha NLS-binding site fail to disrupt CTNNBL1-NLS interactions. Our results identify CTNNBL1 as a unique selective NLS-binding protein with striking differences from karyopherin-alphas.