Fibronectins

Title: Fibronectins
CAS Name: a2-SB glycoproteins
Additional Names: a2-opsonins; CIG; CSP; CAF; GAP A; LETS; Zeta protein
Literature References: High mol wt multifunctional glycoproteins, found on cell surfaces, in body fluids (especially plasma), in soft connective tissue matrices, and in most basement membranes. Although fibronectins apparently function as adhesive ligand-like molecules, the full range of their biological activities and relationships are still being elucidated. Their importance in cell adhesion, oncogenic transformation, reticuloendothelial system function, embryonic differentiation, phagocytosis, hemostasis, and chemotaxis is being studied. Discovered as a result of isoln of a partially purified fraction of human plasma and initially termed "cold-insoluble globulin" or CIG: P. R. Morrison et al., J. Am. Chem. Soc. 70, 3103 (1948). Subsequent studies described various proteins or factors, named according to sources or biological activities, that are now designated as fibronectins. At least two types are known to exist, termed plasma and cellular fibronectin, respectively. Both forms contain subunits of mol wt >200,000, joined by disulfide bonds. They are similar in amino acid compositions, carbohydrate structures and secondary and tertiary structures; they cannot be distinguished in biological activity in assays of cell interactions with substrates or in opsonic activity for macrophages. They differ in their effects on cell morphology, on alignment of transformed cells and on hemagglutination; they also have differences in solubility and in the number of subunits linked by disulfide bonds. Monoclonal antibody studies have indicated that the two forms are distinct: B. T. Atherton, R. O. Hynes, Cell 25, 133 (1981); K. D. Noonan et al., J. Supramol. Struct. Cell. Biochem. 5, Suppl, 302 (1981). Regulation of fibronectin biosynthesis: D. R. Senger et al., Am. J. Physiol. 245, 144 (1983). Structure-function relationships: T. Vartio, A. Vaheri, Trends Biochem. Sci. 8, 442 (1983). Role in cellular adhesion, spreading and cytoskeletal organization: I. Virtanen et al., Nature 298, 660 (1982); in phagocytosis: L. Van de Water et al., Science 220, 201 (1983); in wound healing: G. R. Martin et al., "Regulation of Tissue Structure and Repair by Collagen and Fibronectin" in The Surgical Wound, P. Dineen, C. Hildrick-Smith, Eds. (Lea & Febiger, Philadelphia, 1981) pp 110-122. Use in treatment of corneal trophic ulcer therapy: T. Nishida et al., Arch. Ophthalmol. 101, 1046 (1983). Review of role in cellular adhesion: S. K. Akiyama et al., J. Supramol. Struct. Cell. Biochem. 16, 345-358 (1981); role in inflammation: D. F. Mosher et al., Adv. Inflammation Res. 2, 187-207 (1981); C. Bianco, Ann. N.Y. Acad. Sci. 408, 602-609 (1983); actvity in various disease states: S. K. Akiyama, K. M. Yamada, "Fibronectin in Disease" in Monographs in Pathology No. 24, N. Kaufman, Ed., entitled "Connective Tissue Diseases", B. M. Wagner et al., Eds. (Williams & Wilkins, Baltimore, 1983). General Reviews: E. Pearlstein et al., Mol. Cell. Biochem. 29, 103-128 (1980); M. W. Mosesson, D. L. Amrani, Blood 56, 145-158 (1980); E. Ruoslahti, J. Oral Pathol. 10, 3-13 (1981); R. O. Hynes, K. M. Yamada, J. Cell Biol. 95, 369-377 (1982); R. O. Hynes, Sci. Am. 254, 42-51 (1986).
Fichtelite Ficin Fidarestat Filicinic Acid Filipin

Fibronectin 1

PDB rendering based on 1e88.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols FN1; CIG; ED-B; FINC; FN; FNZ; GFND; GFND2; LETS; MSF
External IDs OMIM: 135600 MGI: 95566 HomoloGene: 1533 ChEMBL: 3810 GeneCards: FN1 Gene
RNA expression pattern
PBB GE FN1 210495 x at tn.png
PBB GE FN1 211719 x at tn.png
PBB GE FN1 212464 s at tn.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 2335 14268
Ensembl ENSG00000115414 ENSMUSG00000026193
UniProt P02751 P11276
RefSeq (mRNA) NM_002026 NM_001276408
RefSeq (protein) NP_002017 NP_001263337
Location (UCSC) Chr 2:
216.23 – 216.3 Mb
Chr 1:
71.59 – 71.65 Mb
PubMed search [1] [2]
The modular structure of fibronectin and its binding domains

Fibronectin is a high-molecular weight (~440kDa) glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins.[1] Similar to integrins, fibronectin binds extracellular matrix components such as collagen, fibrin, and heparan sulfate proteoglycans (e.g. syndecans).

Fibronectin exists as a protein dimer, consisting of two nearly identical monomers linked by a pair of disulfide bonds.[1] The fibronectin protein is produced from a single gene, but alternative splicing of its pre-mRNA leads to the creation of several isoforms.

Two types of fibronectin are present in vertebrates:[1]

  • soluble plasma fibronectin (formerly called "cold-insoluble globulin", or CIg) is a major protein component of blood plasma (300 μg/ml) and is produced in the liver by hepatocytes.
  • insoluble cellular fibronectin is a major component of the extracellular matrix. It is secreted by various cells, primarily fibroblasts, as a soluble protein dimer and is then assembled into an insoluble matrix in a complex cell-mediated process.

Fibronectin plays a major role in cell adhesion, growth, migration, and differentiation, and it is important for processes such as wound healing and embryonic development.[1] Altered fibronectin expression, degradation, and organization has been associated with a number of pathologies, including cancer and fibrosis.[2]