Published online May 12, 2008
doi:10.1083/jcb.200712133
The Journal of Cell Biology, Vol. 181, No. 4, 605-613
The Rockefeller University Press, 0021-9525 $30.00
© 2008 Bass-Zubek et al.
Plakophilin 2: a critical scaffold for PKC
that regulates intercellular junction assembly
Amanda E. Bass-Zubek1,
Ryan P. Hobbs1,
Evangeline V. Amargo1,
Nicholas J. Garcia1,
Sherry N. Hsieh1,
Xinyu Chen1,
James K. Wahl, III3,
Mitchell F. Denning4, and
Kathleen J. Green1,2
1 Department of Pathology and 2 Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
3 Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583
4 Cardinal Bernardin Cancer Center, Loyola University Medical Center, Maywood, IL 60153
Correspondence to K.J. Green: kgreen{at}northwestern.edu
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 C
(PKC
) 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 PKC
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.
Abbreviations used in this paper: BIM, bisindolylmaleimide I; DP, desmoplakin; IF, intermediate filaments; IP, immunoprecipitation; MARCKS, myristoylated alanine-rich PKC substrate; PG, plakoglobin; PKP, plakophilin.
© 2008 Bass-Zubek et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

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