EXT1 cdna clone
EXT1 cDNA Clone
NCBI and Uniprot Product Information
NCBI Description
This gene encodes an endoplasmic reticulum-resident type II transmembrane glycosyltransferase involved in the chain elongation step of heparan sulfate biosynthesis. Mutations in this gene cause the type I form of multiple exostoses. [provided by RefSeq, Jul 2008]
Uniprot Description
EXT1: Glycosyltransferase required for the biosynthesis of heparan-sulfate. The EXT1/EXT2 complex possesses substantially higher glycosyltransferase activity than EXT1 or EXT2 alone. Appears to be a tumor suppressor. Defects in EXT1 are a cause of hereditary multiple exostoses type 1 (EXT1). EXT is a genetically heterogeneous bone disorder caused by genes segregating on human chromosomes 8, 11, and 19 and designated EXT1, EXT2 and EXT3 respectively. EXT is a dominantly inherited skeletal disorder primarily affecting endochondral bone during growth. The disease is characterized by formation of numerous cartilage-capped, benign bone tumors (osteocartilaginous exostoses or osteochondromas) that are often accompanied by skeletal deformities and short stature. In a small percentage of cases exostoses have exhibited malignant transformation resulting in an osteosarcoma or chondrosarcoma. Osteochondromas development can also occur as a sporadic event. Defects in EXT1 are a cause of tricho-rhino-phalangeal syndrome type 2 (TRPS2). A syndrome that combines the clinical features of trichorhinophalangeal syndrome type 1 and multiple exostoses type 1. Affected individuals manifest multiple dysmorphic facial features including large, laterally protruding ears, a bulbous nose, an elongated upper lip, as well as sparse scalp hair, winged scapulae, multiple cartilaginous exostoses, redundant skin, and mental retardation. A chromosomal aberration resulting in the loss of functional copies of TRPS1 and EXT1 has been found in TRPS2 patients. Defects in EXT1 are a cause of chondrosarcoma (CHDSA). It is a malignant neoplasm derived from cartilage cells. Chondrosarcomas range from slow-growing non-metastasizing lesions to highly aggressive metastasizing sarcomas. Belongs to the glycosyltransferase 47 family.
Protein type: EC 2.4.1.225; EC 2.4.1.224; Transferase; Membrane protein, integral; Motility/polarity/chemotaxis; Tumor suppressor; Glycan Metabolism - heparan sulfate biosynthesis
Chromosomal Location of Human Ortholog: 8q24.11
Cellular Component: endoplasmic reticulum; Golgi apparatus; Golgi membrane; integral to endoplasmic reticulum membrane; integral to membrane
Molecular Function: acetylglucosaminyltransferase activity; glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase activity; glucuronosyltransferase activity; N-acetylglucosaminyl-proteoglycan 4-beta-glucuronosyltransferase activity; protein heterodimerization activity; protein homodimerization activity; transferase activity, transferring glycosyl groups
Biological Process: cellular polysaccharide biosynthetic process; glycosaminoglycan biosynthetic process; heparan sulfate proteoglycan biosynthetic process; heparan sulfate proteoglycan biosynthetic process, polysaccharide chain biosynthetic process; ossification; signal transduction; skeletal development
Disease: Chondrosarcoma; Exostoses, Multiple, Type I
