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XB-ART-41478
J Biol Chem August 20, 2010; 285 (34): 26289-94.

Traf2- and Nck-interacting kinase is essential for canonical Wnt signaling in Xenopus axis formation.

Satow R , Shitashige M , Jigami T , Honda K , Ono M , Hirohashi S , Yamada T .


Abstract
Wnt signaling pathways play important roles in various stages of developmental events and several aspects of adult homeostasis. Aberrant activation of Wnt signaling has also been associated with several types of cancer. We have recently identified Traf2- and Nck-interacting kinase (TNIK) as a novel activator of Wnt signaling through a comprehensive proteomic approach in human colorectal cancer cell lines. TNIK is an activating kinase for T-cell factor-4 (TCF4) and essential for the beta-catenin-TCF4 transactivation and colorectal cancer growth. Here, we report the essential role of TNIK in Wnt signaling during Xenopus development. We found that Xenopus TNIK (XTNIK) was expressed maternally and that the functional knockdown of XTNIK by catalytically inactive XTNIK (K54R) or antisense morpholino oligonucleotides resulted in significant malformations with a complete loss of head and axis structures. XTNIK enhanced beta-catenin-induced axis duplication and the expression of beta-catenin-TCF target genes, whereas knockdown of XTNIK inhibited it. XTNIK was recruited to the promoter region of beta-catenin-TCF target genes in a beta-catenin-dependent manner. These results demonstrate that XTNIK is an essential factor for the transcriptional activity of the beta-catenin-TCF complex and dorsal axis determination in Xenopus embryos.

PubMed ID: 20566648
PMC ID: PMC2924048
Article link: J Biol Chem


Species referenced: Xenopus laevis
Genes referenced: nck1 tank tcf4 tnik traf2
Morpholinos: tnik MO1 tnik MO2

References [+] :
Blythe, Chromatin immunoprecipitation in early Xenopus laevis embryos. 2009, Pubmed, Xenbase