Transient interactions drive the lateral clustering of cadherin-23 on membrane

Abstract

Cis and trans-interactions among cadherins secure multicellularity. While the molecular structure of trans-interactions of cadherins is well understood, work to identify the molecular cues that spread the cis-interactions two-dimensionally is still ongoing. Here, we report that transient, weak, yet multivalent, and spatially distributed hydrophobic interactions that are involved in liquid-liquid phase separations of biomolecules in solution, alone can drive the lateral-clustering of cadherin-23 on a membrane. No specific cis-dimer interactions are required for the lateral clustering. In cells, the cis-clustering accelerates cell-cell adhesion and, thus, contributes to cell-adhesion kinetics along with strengthening the junction. Although the physiological connection of cis-clustering with rapid adhesion is yet to be explored, we speculate that the over-expression of cadherin-23 in M2-macrophages may facilitate faster attachments to circulatory tumor cells during metastasis.

Redefining the Structure of Tip Links in Hair Cells

“…The attachments of the individual cadherins were confirmed from the C-terminal GFP tags (Figure a). Because free diffusion of proteins tethered to the membrane is essential for lateral proximity and, therefore, lateral complexation, we confirm the diffusion of proteins via fluorescence recovery after photobleaching (FRAP) experiments on GUVs tethered with Pcdh15 and Cdh23 (Figure S2 and Table S1).…”

“…A lipid membrane limits the diffusion of anchored molecules in two dimensions and, thus, influences the binding affinity of proteins through cooperative interactions and membrane fluctuations. , Cadherins are transmembrane proteins and are naturally confined for lateral diffusion . To identify the existence of any dimers or oligomers of Cdh23 on a two-dimensional membrane, we performed PICUP on GUVs.…”

“…We used an optimal concentration of 5 μM for Cdh23 EC1–27 for PICUP as beyond this we always observed smearing of bands in the SDS–PAGE gel. Notably, at higher concentrations (>4 μM), Cdh23 EC1–27 undergoes liquid–liquid phase separation . We observed dimer bands at ∼650 kDa at all calcium concentrations via PICUP, except at the endolymph Ca 2+ concentration of 50 μM (Figure c).…”