Aggrecan

4MD4176n/aENSG00000157766n/aP16112n/aNM_001135NM_013227NM_001369268n/aNP_001126NP_037359NP_001356197n/aAggrecan (ACAN), also known as cartilage-specific proteoglycan core protein (CSPCP) or chondroitin sulfate proteoglycan 1, is a protein that in humans is encoded by the ACAN gene. This gene is a member of the lectican (chondroitin sulfate proteoglycan) family. The encoded protein is an integral part of the extracellular matrix in cartilagenous tissue and it withstands compression in cartilage.1tdq: Structural basis for the interactions between tenascins and the C-type lectin domains from lecticans: evidence for a cross-linking role for tenascins Aggrecan (ACAN), also known as cartilage-specific proteoglycan core protein (CSPCP) or chondroitin sulfate proteoglycan 1, is a protein that in humans is encoded by the ACAN gene. This gene is a member of the lectican (chondroitin sulfate proteoglycan) family. The encoded protein is an integral part of the extracellular matrix in cartilagenous tissue and it withstands compression in cartilage. Aggrecan is a proteoglycan, or a protein modified with large carbohydrates; the human form of the protein is 2316 amino acids long and can be expressed in multiple isoforms due to alternative splicing. Aggrecan is a high molecular weight (1x106 < M < 3x106) proteoglycan. It exhibits a bottlebrush structure, in which chondroitin sulfate and keratan sulfate glycosaminoglycan (GAG) chains are attached to an extended protein core. Aggrecan has a molecular mass >2,500 kDa. The core protein (~300 kDa) has around 100 GAG chains attached to it. Aggrecan consists of two globular structural domains (G1 and G2) at the N-terminal end and one globular domain (G3) at the C-terminal end, separated by a large extended domain (CS) heavily modified with GAGs. (N-G1-G2-CS-G3-C) The two main modifier moieties are themselves arranged into distinct regions, a chondroitin sulfate and a keratan sulfate region. The three globular domains, G1, G2, and G3 are involved in aggregation, hyaluronan binding, cell adhesion, and chondrocyte apoptosis. Along with type-II collagen, aggrecan forms a major structural component of cartilage, particularly articular cartilage. The aggrecan family includes other important members such as versican, also named PG-M, neurocan, brevican and the cell surface HA receptor CD44. They are modular proteoglycans containing combinations of structural motifs, such as EGF-like domains, carbohydrate recognition domains (CRD), complement binding protein (CBP)-like domains, immunoglobulin folds and proteoglycan tandem repeats.