PKCδ is essential for Dishevelled function in a noncanonical Wnt pathway that regulates Xenopus convergent extension movements

Abstract

Protein kinase C (PKC) has been implicated in the Wnt signaling pathway; however, its molecular role is poorly understood. We identified novel genes encoding δ-type PKC in the Xenopus EST databases. Loss of PKCδ function revealed that it was essential for convergent extension during gastrulation. We then examined the relationship between PKCδ and the Wnt pathway. PKCδ was translocated to the plasma membrane in response to Frizzled signaling. In addition, loss of PKCδ function inhibited the translocation of Dishevelled and the activation of c-Jun N-terminal kinase (JNK) by Frizzled. Furthermore, PKCδ formed a complex with Dishevelled, and the activation of PKCδ by phorbol ester was sufficient for Dishevelled translocation and JNK activation. Thus, PKCδ plays an essential role in the Wnt/JNK pathway by regulating the localization and activity of Dishevelled.

Keywords

• PKCδ
• Xenopus
• gastrulation
• convergent extension
• noncanonical Wnt pathway