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Publication Abstract from PubMed

Catenin-beta-like protein 1 (CTNNBL1) is a highly conserved protein with multiple functions, one of which is to act as an interaction partner of the antibody-diversification enzyme activation-induced cytidine deaminase (AID) for its nuclear import and subnuclear trafficking. Here, the crystal structure of full-length human CTNNBL1 is reported. The protein contains six armadillo (ARM) repeats that pack into a superhelical ARM domain. This ARM domain is unique within the ARM protein family owing to the presence of several unusual structural features. Moreover, CTNNBL1 contains significant and novel non-ARM structures flanking both ends of the central ARM domain. A strong continuous hydrophobic core runs through the whole structure, indicating that the ARM and non-ARM structures fold together to form an integral structure. This structure defines a highly restrictive and discriminatory protein-binding groove that is not observed in other ARM proteins. The presence of a cluster of histidine residues in the groove implies a pH-sensitive histidine-mediated mechanism that may regulate protein binding activity. The many unique structural features of CTNNBL1 establish it as a distinct member of the ARM protein family. The structure provides critical insights into the molecular interactions between CTNNBL1 and its protein partners, especially AID.

The structure of full-length human CTNNBL1 reveals a distinct member of the armadillo-repeat protein family.,Huang X, Wang G, Wu Y, Du Z Acta Crystallogr D Biol Crystallogr. 2013 Aug;69(Pt 8):1598-608. doi:, 10.1107/S0907444913011360. Epub 2013 Jul 20. PMID:23897482^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.