Giant cadherins Fat and Dachsous self-bend to organize properly spaced intercellular junctions

Y Tsukasaki, N Miyazaki… - Proceedings of the …, 2014 - National Acad Sciences
Y Tsukasaki, N Miyazaki, A Matsumoto, S Nagae, S Yonemura, T Tanoue, K Iwasaki…
Proceedings of the National Academy of Sciences, 2014National Acad Sciences
The cadherins Fat and Dachsous regulate cell polarity and proliferation via their heterophilic
interactions at intercellular junctions. Their ectodomains are unusually large because of
repetitive extracellular cadherin (EC) domains, which raises the question of how they fit in
regular intercellular spaces. Cadherins typically exhibit a linear topology through the binding
of Ca2+ to the linker between the EC domains. Our electron-microscopic observations of
mammalian Fat4 and Dachsous1 ectodomains, however, revealed that, although their N …
The cadherins Fat and Dachsous regulate cell polarity and proliferation via their heterophilic interactions at intercellular junctions. Their ectodomains are unusually large because of repetitive extracellular cadherin (EC) domains, which raises the question of how they fit in regular intercellular spaces. Cadherins typically exhibit a linear topology through the binding of Ca2+ to the linker between the EC domains. Our electron-microscopic observations of mammalian Fat4 and Dachsous1 ectodomains, however, revealed that, although their N-terminal regions exhibit a linear configuration, the C-terminal regions are kinked with multiple hairpin-like bends. Notably, certain EC–EC linkers in Fat4 and Dachsous1 lost Ca2+-binding amino acids. When such non–Ca2+-binding linkers were substituted for a normal linker in E-cadherin, the mutant E-cadherins deformed more extensively than the wild-type molecule. To simulate cadherin structures with non–Ca2+-binding linkers, we used an elastic network model and confirmed that bent configurations can be generated by deformation of non–Ca2+-binding linkers. These findings suggest that Fat and Dachsous self-bend due to the loss of Ca2+-binding amino acids from specific EC–EC linkers, and can therefore adapt to confined spaces.
National Acad Sciences