MRC1
Description
The MRC1 (mannose receptor C-type 1) is a protein-coding gene located on chromosome 10.
MRC1, also known as the mannose receptor (CD206), is a type I transmembrane protein primarily found on macrophages, immature dendritic cells, and liver sinusoidal endothelial cells. It is a member of a family of endocytic receptors that includes Endo180, M-type PLA2R, and DEC-205. MRC1 recognizes terminal mannose, N-acetylglucosamine, and fucose residues on glycans attached to proteins found on the surface of microorganisms. This recognition plays a role in both the innate and adaptive immune systems. Additional functions include the clearance of glycoproteins from circulation, including sulphated glycoprotein hormones and glycoproteins released in response to pathological events. MRC1 continuously recycles between the plasma membrane and endosomal compartments in a clathrin-dependent manner.
The extracellular portion of MRC1 is composed of 8 consecutive C-type carbohydrate recognition domains (CRDs) closest to the plasma membrane, followed by a single fibronectin type II repeat domain and an N-terminal cysteine-rich domain. The cytoplasmic tail is not capable of signal transduction in isolation, since it lacks the appropriate signaling motifs.
The N-terminal cysteine-rich domain is homologous to the ricin B chain and binds to sulphated sugar moieties, with particularly high affinity for N-Acetylgalactosamine and galactose residues sulphated at positions 3 and 4 of their pyranose rings.
MRC1 is also known as CD206, CLEC13D, CLEC13DL, MMR, MRC1L1, bA541I19.1, hMR.
