Polarized distribution of organelles and molecules inside a cell is vital for a range of cellular processes and its loss is frequently encountered in disease. Polarization during planar cell migration is a special condition in which cellular orientation is triggered by cell-cell contact. We demonstrate that the protein Daple (CCDC88C) is a component of cell junctions in epithelial cells which serves like a cellular ''compass'' for establishing and maintaining contact-triggered planar polarity. Furthermore, these processes may be mediated through interaction with the polarity regulator PARD3. This interaction, mediated by Daple's PDZ-binding motif (PBM) and the third PDZ domain of PARD3, is fine-tuned by tyrosine phosphorylation on Daple's PBM by receptor and non-receptor tyrosine kinases, such as Src. Hypophosphorylation strengthens the interaction, whereas hyperphosphorylation disrupts it, thereby revealing an unexpected role of Daple as a platform for signal integration and gradient sensing for tyrosine-based signals within the planar cell polarity pathway.

No abstract

No abstract

We present a 14-year-old male with chronic, recurrent pyoderma gangrenosum that resolved after treatment of latent tuberculosis. As pyoderma gangrenosum often occurs secondary to underlying diseases, we describe latent tuberculosis as a possible trigger for pyoderma gangrenosum.

Highlights• Daple localizes to cell junctions via its PDZ binding motif (PBM)• Junction-localized Daple regulates planar cell migration • Daple's PBM directly binds the polarity regulator PARD3• The Daple•PARD3 interface senses gradients of tyrosine-based signals Summary Polarized distribution of organelles and molecules inside a cell is vital for a range of cellular processes and its loss is frequently encountered in disease. Polarization during planar cell migration is a special condition in which cellular orientation is triggered by cell-cell contact. Here, we demonstrate that the multi-modular signaling scaffold Daple (CCDC88C) is a component of cell junctions in epithelial cells which serves like a cellular 'compass' for establishing and maintaining contact-triggered planar polarity via its interaction with the polarity regulator PARD3. This interaction, mediated by Daple's PDZ-binding motif (PBM) and the third PDZ domain of PARD3, is fine-tuned by two tyrosine phosphoevents on Daple's PBM that are triggered by a multitude of growth factors. Hypophosphorylation strengthens the interaction, whereas hyperphosphorylation disrupts it. These findings reveal an unexpected role of Daple within the planar cell polarity pathway as a platform for signal integration and gradient sensing for tyrosinebased signals.