Tumor necrosis factor-inducible gene 6 protein also known as TNF-stimulated gene 6 protein or TSG-6 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''TNFAIP6'' (tumor necrosis factor, alpha-induced protein 6)

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Structure and function

TSG-6 is a 30

kDa The dalton or unified atomic mass unit (symbols: Da or u, respectively) is a unit of mass defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. It is a non-SI unit accepted f ...

secreted protein that contains a

hyaluronan Hyaluronic acid (; abbreviated HA; conjugate acid, conjugate base hyaluronate), also called hyaluronan, is an anion#Anions and cations, anionic, Sulfation, nonsulfated glycosaminoglycan distributed widely throughout connective tissue, connective ...

-binding LINK domain a and thus is a member of the hyaluronan-binding protein family, also called

hyaladherin Hyaladherins, also known as hyaluronan-binding proteins, are proteins capable of binding to hyaluronic acid. Most hyaladherins belong to the Link module superfamily, including its main receptor CD44, hyalectans and TSG-6. In addition there is a d ...

s. The hyaluronan-binding domain is known to be involved in

extracellular matrix In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and bio ...

stability and

cell migration Cell migration is a central process in the development and maintenance of multicellular organisms. Tissue formation during embryogenesis, embryonic development, wound healing and immune system, immune responses all require the orchestrated movemen ...

. This protein has been shown to form a stable,

covalent A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atom ...

complex with inter-alpha-inhibitor ( IαI), and thus enhance the

serine protease Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serin ...

inhibitory activity of IαI, which is important in the protease network associated with inflammation. The expression of this gene can be induced by a number of signalling molecules, principally tumor necrosis factor α (

TNF-α Tumor necrosis factor (TNF), formerly known as TNF-α, is a chemical messenger produced by the immune system that induces inflammation. TNF is produced primarily by activated macrophages, and induces inflammation by binding to its receptors o ...

) and interleukin-1 ( IL-1). The expression can also be induced by mechanical stimuli in vascular smooth muscle cells, and is found to be correlated with

proteoglycan Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a serine (Ser) residue to w ...

synthesis and aggregation. TSG-6 has been shown to modulate macrophage plasticity and signal the transition of LPS-treated macrophages from pro- to anti-inflammatory phenotype. TSG-6 also interacts with a number of matrix associated molecules such as

aggrecan 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 pr ...

versican Versican is a large extracellular matrix proteoglycan that is present in a variety of human tissues. It is encoded by the ''VCAN'' gene. Versican is a large chondroitin sulfate proteoglycan with an apparent molecular mass of more than 1000kDa. I ...

thrombospondin Thrombospondins (TSPs) are a family of secreted glycoproteins with antiangiogenic functions. Due to their dynamic role within the extracellular matrix they are considered matricellular proteins. The first member of the family, thrombospondin 1 ...

(1&2), pentraxin-3 and

fibronectin Fibronectin is a high- molecular weight (~500-~600 kDa) glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins. Fibronectin also binds to other extracellular matrix proteins such as col ...

Structure and function

References

Further reading