Cadherins are cell-cell interaction molecules. FAT4 plays a role in the maintenance of planar cell polarity as well as in inhibition of YAP1-mediated neuroprogenitor cell proliferation and differentiation. Heterophilic interaction with DCHS1; this interaction affects their respective protein levels. Interacts (via cytoplasmic domain) with MPDZ. Forms a complex with PALS1 and MPDZ. In the kidney, localizes to primary cilia. Widely expressed. Expressed in all layers of the developing brain, with expression being most prominent at the ventricular margin. Deficient mice exhibit postnatal lethality, growth retardation, small lungs, abnormal cochlea morphology, abnormal kidney morphology, cardiovascular abnormalities and skeletal abnormalities. DCHS1 and FAT4 single mutants and DCHS1/FAT4 double mutants have similar phenotypes. Truncated N-terminus. Truncated N-terminus.