Patched Domain Containing Protein 4 (PTCHD4)

C6orf138 Belongs to the patched family. Contains 1 SSD (sterol-sensing) domain. The sterol-sensing domain (SSD) consists of approximately 180 amino acids organised into a cluster of five consecutive membrane-spanning domains and is found in proteins which have key roles in different aspects of cholesterol homeostasis or cholesterol-linked signalling such as sterol-regulated movement or the trafficking of specific cargoes. Examples of proteins containing SSDs include the Hedgehog signalling protein (Patched protein) from Drosophila; 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), which is involved in the control of cholesterol biosynthesis; SREBP cleavage-activating protein (SCAP); the Niemann-Pick type C (NPC1) protein; and a number of bacterial drug resistance proteins.