Fibronectin type II domain is a collagen-binding protein domain. Fibronectin is a multi-domain

glycoprotein Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as g ...

, found in a soluble form in plasma, and in an insoluble form in loose

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue ...

and

basement membranes The basement membrane is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tissues including mesothelium and ...

, that binds cell surfaces and various compounds including collagen, fibrin, heparin, DNA, and

actin Actin is a protein family, family of Globular protein, globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in myofibril, muscle fibrils. It is found in essentially all Eukaryote, eukaryotic cel ...

. Fibronectins are involved in a number of important functions e.g.,

wound healing Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue. In undamaged skin, the epidermis (surface, epithelial layer) and dermis (deeper, connective layer) form a protective barrier aga ...

; cell adhesion;

blood coagulation Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism o ...

; cell differentiation and migration; maintenance of the cellular

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is comp ...

; and tumour metastasis. The major part of the sequence of fibronectin consists of the repetition of three types of domains, which are called type I, II, and III. Type II domain is approximately sixty amino acids long, contains four conserved cysteines involved in disulfide bonds and is part of the collagen-binding region of fibronectin. Type II domains occur two times in fibronectin. Type II domains have also been found in a range of proteins including blood coagulation factor XII; bovine seminal plasma proteins PDC-109 (BSP-A1/A2) and BSP-A3; cation-independent mannose-6-phosphate receptor; mannose receptor of macrophages; 180 Kd secretory phospholipase A2 receptor; DEC-205 receptor; 72 Kd and 92 Kd type IV collagenase (); and hepatocyte growth factor activator.

Fibronectin type II domain and Lipid bilayer interaction

Fibronectin type II domain is part of the extracellular portions of EphA2 receptor proteins. FN2 domain on EphA2 receptors bears positively-charged components, namely K441 and R443, which attract and almost exclusively bind to anionic lipids such as anionic membrane lipid phosphatidylglycerol. K441 and R443 together make up a membrane-binding motif that allows EphA2 receptors to attach to the cell membrane.

Human proteins containing this domain

BSPH1; ELSPBP1; F12;

FN1 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 collagen, f ...

; HGFAC;

IGF2R Insulin-like growth factor 2 receptor (IGF2R), also called the cation-independent mannose-6-phosphate receptor (CI-MPR) is a protein that in humans is encoded by the ''IGF2R'' gene. IGF2R is a multifunctional protein receptor that binds insulin- ...

; LY75; MMP2; MMP9;

MRC1 The mannose receptor (Cluster of Differentiation 206, CD206) is a C-type lectin primarily present on the surface of macrophages, immature dendritic cells and liver sinusoidal endothelial cells, but is also expressed on the surface of skin cells ...

;

MRC1L1 The mannose receptor (Cluster of Differentiation 206, CD206) is a C-type lectin primarily present on the surface of macrophages, immature dendritic cells and liver sinusoidal endothelial cells, but is also expressed on the surface of skin cells ...

;

MRC2 The mannose receptor (Cluster of Differentiation 206, CD206) is a C-type lectin primarily present on the surface of macrophages, immature dendritic cells and liver sinusoidal endothelial cells, but is also expressed on the surface of skin cells ...

;

PLA2R1 Secretory phospholipase A2 receptor is a protein that in humans is encoded by the ''PLA2R1'' gene. Clinical significance M-type phospholipase A2 receptor is the major antigen in idiopathic membranous nephropathy Membranous glomerulonephritis ...

; SEL1L; *Fibronectin type I domain: F12;

; HGFAC; PLAT;

References

External links

Fibronectin type-II collagen-binding domain
in PROSITE Protein domains Peripheral membrane proteins {{membrane-protein-stub