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Defining desmosomal plakophilin-3 interactions.

Bonné S, Gilbert B, Hatzfeld M, Chen X, Green KJ, van Roy F - J. Cell Biol. (2003)

Bottom Line: We found that PKP3 binds all three desmogleins, desmocollin (Dsc) 3a and -3b, and possibly also Dsc1a and -2a.Evidence was found for the presence of at least two DP-PKP3 interaction sites.Together, these results show that PKP3, whose epithelial and epidermal desmosomal expression pattern and protein interaction repertoire are broader than those of PKP1 and -2, is a unique multiprotein binding element in the basic architecture of a vast majority of epithelial desmosomes.

View Article: PubMed Central - PubMed

Affiliation: Molecular Cell Biology Unit, Department for Molecular Biomedical Research, Flanders Interuniversity Institute for Biotechnology (VIB)-Ghent University, B-9000 Ghent, Belgium.

ABSTRACT
Plakophilin 3 (PKP3) is a recently described armadillo protein of the desmosomal plaque, which is synthesized in simple and stratified epithelia. We investigated the localization pattern of endogenous and exogenous PKP3 and fragments thereof. The desmosomal binding properties of PKP3 were determined using yeast two-hybrid, coimmunoprecipitation and colocalization experiments. To this end, novel mouse anti-PKP3 mAbs were generated. We found that PKP3 binds all three desmogleins, desmocollin (Dsc) 3a and -3b, and possibly also Dsc1a and -2a. As such, this is the first protein interaction ever observed with a Dsc-b isoform. Moreover, we determined that PKP3 interacts with plakoglobin, desmoplakin (DP) and the epithelial keratin 18. Evidence was found for the presence of at least two DP-PKP3 interaction sites. This finding might explain how lateral DP-PKP interactions are established in the upper layers of stratified epithelia, increasing the size of the desmosome and the number of anchoring points available for keratins. Together, these results show that PKP3, whose epithelial and epidermal desmosomal expression pattern and protein interaction repertoire are broader than those of PKP1 and -2, is a unique multiprotein binding element in the basic architecture of a vast majority of epithelial desmosomes.

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Colocalization of GFP-tagged PKP3 and myc-tagged Dsc1a and Dsc2a in cotransfected HEK293T cells. Exogenous GFP-tagged PKP3 colocalizes with Dsc1a and Dsc2a at cell–cell contacts (a vs. b and d vs. e, arrows). Control DAPI stainings are shown (c and f). Bar, 30 μm (a–f).
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fig9: Colocalization of GFP-tagged PKP3 and myc-tagged Dsc1a and Dsc2a in cotransfected HEK293T cells. Exogenous GFP-tagged PKP3 colocalizes with Dsc1a and Dsc2a at cell–cell contacts (a vs. b and d vs. e, arrows). Control DAPI stainings are shown (c and f). Bar, 30 μm (a–f).

Mentions: In vitro colocalization between PKP3 and Dscs was observed in cotransfection experiments. PKP3 was expressed as a fusion protein in-frame with a GFP tag, whereas Dsc proteins contained a myc tag. GFP-tagged PKP3 colocalized with exogenous Dsc1a (Fig. 9 , a–c) and Dsc2a (Fig. 9, d–f) at cell–cell contacts in cotransfected HEK293T cells. These results provide further evidence for direct in vivo interactions between PKP3 and Dscs.


Defining desmosomal plakophilin-3 interactions.

Bonné S, Gilbert B, Hatzfeld M, Chen X, Green KJ, van Roy F - J. Cell Biol. (2003)

Colocalization of GFP-tagged PKP3 and myc-tagged Dsc1a and Dsc2a in cotransfected HEK293T cells. Exogenous GFP-tagged PKP3 colocalizes with Dsc1a and Dsc2a at cell–cell contacts (a vs. b and d vs. e, arrows). Control DAPI stainings are shown (c and f). Bar, 30 μm (a–f).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172904&req=5

fig9: Colocalization of GFP-tagged PKP3 and myc-tagged Dsc1a and Dsc2a in cotransfected HEK293T cells. Exogenous GFP-tagged PKP3 colocalizes with Dsc1a and Dsc2a at cell–cell contacts (a vs. b and d vs. e, arrows). Control DAPI stainings are shown (c and f). Bar, 30 μm (a–f).
Mentions: In vitro colocalization between PKP3 and Dscs was observed in cotransfection experiments. PKP3 was expressed as a fusion protein in-frame with a GFP tag, whereas Dsc proteins contained a myc tag. GFP-tagged PKP3 colocalized with exogenous Dsc1a (Fig. 9 , a–c) and Dsc2a (Fig. 9, d–f) at cell–cell contacts in cotransfected HEK293T cells. These results provide further evidence for direct in vivo interactions between PKP3 and Dscs.

Bottom Line: We found that PKP3 binds all three desmogleins, desmocollin (Dsc) 3a and -3b, and possibly also Dsc1a and -2a.Evidence was found for the presence of at least two DP-PKP3 interaction sites.Together, these results show that PKP3, whose epithelial and epidermal desmosomal expression pattern and protein interaction repertoire are broader than those of PKP1 and -2, is a unique multiprotein binding element in the basic architecture of a vast majority of epithelial desmosomes.

View Article: PubMed Central - PubMed

Affiliation: Molecular Cell Biology Unit, Department for Molecular Biomedical Research, Flanders Interuniversity Institute for Biotechnology (VIB)-Ghent University, B-9000 Ghent, Belgium.

ABSTRACT
Plakophilin 3 (PKP3) is a recently described armadillo protein of the desmosomal plaque, which is synthesized in simple and stratified epithelia. We investigated the localization pattern of endogenous and exogenous PKP3 and fragments thereof. The desmosomal binding properties of PKP3 were determined using yeast two-hybrid, coimmunoprecipitation and colocalization experiments. To this end, novel mouse anti-PKP3 mAbs were generated. We found that PKP3 binds all three desmogleins, desmocollin (Dsc) 3a and -3b, and possibly also Dsc1a and -2a. As such, this is the first protein interaction ever observed with a Dsc-b isoform. Moreover, we determined that PKP3 interacts with plakoglobin, desmoplakin (DP) and the epithelial keratin 18. Evidence was found for the presence of at least two DP-PKP3 interaction sites. This finding might explain how lateral DP-PKP interactions are established in the upper layers of stratified epithelia, increasing the size of the desmosome and the number of anchoring points available for keratins. Together, these results show that PKP3, whose epithelial and epidermal desmosomal expression pattern and protein interaction repertoire are broader than those of PKP1 and -2, is a unique multiprotein binding element in the basic architecture of a vast majority of epithelial desmosomes.

Show MeSH
Related in: MedlinePlus