Casein kinase I phosphorylates the Armadillo protein and induces its degradation in Drosophila.

ABSTRACT: Casein kinase I (CKI) was recently reported as a positive regulator of Wnt signaling in vertebrates and Caenorhabditis elegans. To elucidate the function of Drosophila CKI in the wingless (Wg) pathway, we have disrupted its function by double-stranded RNA-mediated interference (RNAi). While previous findings were mainly based on CKI overexpression, this is the first convincing loss-of-function analysis of CKI. Surprisingly, CKIalpha- or CKIepsilon-RNAi markedly elevated the Armadillo (Arm) protein levels in Drosophila Schneider S2R+ cells, without affecting its mRNA levels. Pulse-chase analysis showed that CKI-RNAi stabilizes Arm protein. Moreover, Drosophila embryos injected with CKIalpha double-stranded RNA showed a naked cuticle phenotype, which is associated with activation of Wg signa

SUBMITTER: Yanagawa S 

PROVIDER: S-EPMC125941 | biostudies-literature | 2002 Apr

REPOSITORIES: biostudies-literature