EGF-induced ERK activation promotes CK2-mediated disassociation of alpha-Catenin from beta-Catenin and transactivation of beta-Catenin.
Increased transcriptional activity of beta-catenin resulting from Wnt/Wingless-dependent or -independent signaling has been detected in many types of human cancer, but the underlying mechanism of Wnt-independent regulation remains unclear. We demonstrate here that EGFR activation results in disruption of the complex of beta-catenin and alpha-catenin, thereby abrogating the inhibitory effect ... of alpha-catenin on beta-catenin transactivation via CK2alpha-dependent phosphorylation of alpha-catenin at S641. ERK2, which is activated by EGFR signaling, directly binds to CK2alpha via the ERK2 docking groove and phosphorylates CK2alpha primarily at T360/S362, subsequently enhancing CK2alpha activity toward alpha-catenin phosphorylation. In addition, levels of alpha-catenin S641 phosphorylation correlate with levels of ERK1/2 activity in human glioblastoma specimens and with grades of glioma malignancy. This EGFR-ERK-CK2-mediated phosphorylation of alpha-catenin promotes beta-catenin transactivation and tumor cell invasion. These findings highlight the importance of the crosstalk between EGFR and Wnt pathways in tumor development.
Mesh Terms:
Amino Acid Sequence, Binding Sites, Casein Kinase II, Enzyme Activation, Epidermal Growth Factor, Extracellular Signal-Regulated MAP Kinases, Glioblastoma, Humans, Molecular Sequence Data, Neoplasm Invasiveness, Phosphorylation, Phosphoserine, Protein Binding, Receptor, Epidermal Growth Factor, Transcriptional Activation, alpha Catenin, beta Catenin
Amino Acid Sequence, Binding Sites, Casein Kinase II, Enzyme Activation, Epidermal Growth Factor, Extracellular Signal-Regulated MAP Kinases, Glioblastoma, Humans, Molecular Sequence Data, Neoplasm Invasiveness, Phosphorylation, Phosphoserine, Protein Binding, Receptor, Epidermal Growth Factor, Transcriptional Activation, alpha Catenin, beta Catenin
Mol. Cell
Date: Nov. 25, 2009
PubMed ID: 19941816
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