Abstract
Cadherins, Ca2+-dependent adhesion molecules, are crucial for cell-cell junctions and remodeling. Cadherins form inter-junctional lattices by the formation of both cis and trans dimers. Here, we directly visualize and quantify the spatiotemporal dynamics of wild-type and dimer mutant N-cadherin interactions using time-lapse imaging of junction assembly, disassembly and a FRET reporter to assess Ca2+-dependent interactions. A trans dimer mutant (W2A) and a cis mutant (V81D/V174D) exhibited an increased Ca2+-sensitivity for the disassembly of trans dimers compared to the WT, while another mutant (R14E) was insensitive to Ca2+-chelation. Time-lapse imaging of junction assembly and disassembly, monitored in 2D and 3D (using cellular spheroids), revealed kinetic differences in the different mutants as well as different behaviors in the 2D and 3D environment. Taken together, these data provide new insights into the role that the cis and trans dimers play in the dynamic interactions of cadherins.
Highlights
Cell-cell adhesion and signaling is essential for the formation and maintenance of tissues and organs in multicellular organisms
We examined the assembly of cell lines stably overexpressing N-cadherin WT molecules or the mutations W2A, R14E and V81D/V174D into threedimensional cellular spheroids using light sheet microscopy
Three binding interfaces for cadherin-cadherin interactions have been reported far: two of them are involved in trans interactions, the X-dimer and the strand-swapped dimer, and the third is involved in cis interactions
Summary
Cell-cell adhesion and signaling is essential for the formation and maintenance of tissues and organs in multicellular organisms. Cadherins are usually organized in adherens junctions, points of adhesion between neighboring cells. Four Ca2+-binding sites for three Ca2+-ions each are located between the cadherin repeats. Calcium binding at these sites leads to a rigidification of the extracellular domain that is essential for adhesion. Cadherins could play an important role as Ca2+-sensors, monitoring fluctuations in extracellular Ca2+, e.g. at the neuronal synapse, and transferring this information to the inside of the cell via cytoplasmic binding partners. In order to investigate such physiological functions of the cadherins, it is important to understand, in living cells, the cis and trans binding mechanism of cadherins and its regulation by extracellular Ca2+
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
