Protein Domain : Fetuin-A-type cystatin domain IPR025760

Type	Domain
Description	The cystatin superfamily consists of a large group of cystatin domain- containing proteins, most of which are reversible and tight-binding inhibitorsof the papain (C1) and legumain (C13) families of cysteine proteases. Fetuins have been identified as main members of the cystatin superfamily and arecomposed of fetuin-A and fetuin-B. Fetuins are characterised by the presence of 2 N-terminally located cystatin-like repeats and a uniqueC-terminal domain which is not present in other proteins of the cystatin family [, , ].Fetuin-A [ , , , , ] also called alpha-2-HS-glycoprotein, bone sialic acid-containing protein (BSP), countertrypin or PP63, is expressed in a tissue- and development-specific pattern which seems to be significantly different betweenspecies. A wide functional diversity of fetuin-A has been observed. It has been shown to function in many physiological aspects, such as fatty acidtransport, regulation of insulin activity and hepatocyte-growth-factor activity, response to systemic inflammation, and inhibition of unwantedmineralization. It has been demonstrated that fetuin-A plays important roles during developmental processes, including osteogenesis, myotubule, fetal brainand nervous system development. Human fetuin is a heterodimer of chain A and B, which are derived by cleavage of a connecting peptide from a commonprecursor. Snake fetuin family proteins (antihemorrhagic proteins HSF, BJ46a and MSF and HLP-A and HLP-B) show a significant degree of sequence homology tofetuin-A [ ].The cystatin fold is formed by a five stranded anti-parallel β-sheet wrapped around a five-turn α-helix []. Fetuin contains twelve conserved cysteines involved in six disulphide bonds. Eleven of the twelve invariant cysteines are located within the cystatin-likerepeats. The 12th cysteine is located near the C terminus of the protein, separated by a region of variable length.
Short Name	Cystatin_Fetuin_A