ABSTRACT
In 1993, Ichijo et al. cloned and characterized new transforming growth factor-β1 (TGF-β1)-binding proteins from porcine uterus membranes [1]. The proteins that they termed “ colin” had both collagen-like and brinogen-like domains. Since then, many proteins possessing these structural characteristics have been identi ed in both vertebrates and invertebrates at the protein and cDNA level (Table 34.1). Ficolins are now recognized as a family of proteins that have both collagen-like and brinogen-like domains, [2-6] and their mRNA has been identi ed in a variety of tissues. To date, the majority of colins characterized at the protein level are lectins that have a common binding speci city for N-acetyl group-containing sugar such as N-acetylglucosamine (GlcNAc). Ficolins that are present in serum might have a crucial role in innate immunity by activating the complement system via the lectin pathway in a manner similar to mannose-binding lectin (MBL) of the collectin family [7]. It is possible that the nonserum colins perform a similar role to the serum colins.
