Polycystin refers to a group of proteins primarily associated with the function of kidney cells. These proteins are encoded by the PKD1 and PKD2 genes and play a crucial role in maintaining the structure and function of renal tubules. Mutations in these genes can lead to polycystic kidney disease (PKD), a genetic disorder characterized by the formation of fluid-filled cysts in the kidneys. In addition to their role in the kidneys, polycystins are also involved in various cellular processes, including cell signaling and the regulation of cell growth. They are found in other tissues, such as the liver and pancreas, indicating their importance in overall organ function and health. Understanding polycystins is essential for developing treatments for related diseases.