CLEC3B (C-type lectin domain family 3-member B; also Tetranectin) is a 20 kDa, secreted member of the C type lectin superfamily. It is produced by multiple cell types including monocytes, neutrophils, fibroblasts, hepatocytes and various endocrine cells. Although named Tetranectin, CLEC3B is actually a nondisulfide linked homotrimer. It binds to plasminogen, sulfated polysaccharides, and fibrin. Human CLEC3B precursor is 202 amino acids (aa) in length. It contains a signal sequence (aa 1-21), a coiled coil region that mediates trimerization (aa 26-52) and a C type lectin domain (aa 77-198). CLEC3B contains O-linked glycosylation. Mature human CLEC3B is 81% aa identical to mouse CLEC3B.