Background of the antigen
The cadherins represent a family of Ca2+-dependent adhesion molecules that function to mediate cell to cell binding that is critical for the maintenance of structure and morphogenesis. Cadherins contain a large extracellular domain at the N-terminus, which is characterized by a series of five homologous repeats, the most distal of which is thought to be responsible for binding specificity. The relatively short C-terminal intracellular domain interacts with a variety of cytoplasmic proteins, including beta-catenin, to regulate cadherin function. The cadherin superfamily includes cadherins, protocadherins, desmogleins and desmocollins. FAT4 (FAT tumor suppressor homolog 4), also known as FAT-J, CDHF14 or CDHR11, is a 4,981 amino acid single-pass type I membrane protein that belongs to the protocadherin subfamily of cadherins and localizes to the primary cilia of kidney. Widely expressed, FAT4 contains thirty-four cadherin domains, six EGF-like domains and two laminin G-like domains. FAT4 may function in the regulation of planar cell polarity.