Plakophilin 2: a critical scaffold for PKCα that regulates intercellular junction assembly

AE Bass-Zubek, RP Hobbs, EV Amargo… - The Journal of cell …, 2008 - rupress.org
AE Bass-Zubek, RP Hobbs, EV Amargo, NJ Garcia, SN Hsieh, X Chen, JK Wahl III…
The Journal of cell biology, 2008rupress.org
Plakophilins (PKPs) are armadillo family members related to the classical cadherin-
associated protein p120ctn. PKPs localize to the cytoplasmic plaque of intercellular
junctions and participate in linking the intermediate filament (IF)-binding protein
desmoplakin (DP) to desmosomal cadherins. In response to cell–cell contact, PKP2
associates with DP in plaque precursors that form in the cytoplasm and translocate to
nascent desmosomes. Here, we provide evidence that PKP2 governs DP assembly …
Plakophilins (PKPs) are armadillo family members related to the classical cadherin-associated protein p120ctn. PKPs localize to the cytoplasmic plaque of intercellular junctions and participate in linking the intermediate filament (IF)-binding protein desmoplakin (DP) to desmosomal cadherins. In response to cell–cell contact, PKP2 associates with DP in plaque precursors that form in the cytoplasm and translocate to nascent desmosomes. Here, we provide evidence that PKP2 governs DP assembly dynamics by scaffolding a DP–PKP2–protein kinase Cα (PKCα) complex, which is disrupted by PKP2 knockdown. The behavior of a phosphorylation-deficient DP mutant that associates more tightly with IF is mimicked by PKP2 and PKCα knockdown and PKC pharmacological inhibition, all of which impair junction assembly. PKP2 knockdown is accompanied by increased phosphorylation of PKC substrates, raising the possibility that global alterations in PKC signaling may contribute to pathogenesis of congenital defects caused by PKP2 deficiency.
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