A Role for Kaiso-p120ctn Complexes in Cancer?

Kaiso belongs to the zinc finger and broad-complex, tramtrack and bric-a-brac/poxvirus and zinc finger (BTB/POZ) protein family that has been implicated in tumorigenesis. Kaiso was first discovered in a complex with the armadillo-domain protein p120ctn and later shown to function as a transcriptional repressor. As p120ctn seems to relieve Kaiso-mediated repression, its altered intracellular localization in some cancer cells might result in aberrant Kaiso nuclear activity. Intriguingly, Kaiso's target genes include both methylated and sequence-specific recognition sites. The latter include genes that are modulated by the canonical Wnt (beta-catenin-T-cell factor) signalling pathway. Further interest in Kaiso stems from findings that its cytoplasmic versus nuclear localization is modulated by complex cues from the microenvironment.