Syndecans

Syndecans are single transmembrane domain proteins that are thought to act as coreceptors, especially for G protein-coupled receptors. These core proteins carry three to five heparan sulfate and chondroitin sulfate chains which allow for interaction with a large variety of ligands including fibroblast growth factors, vascular endothelial growth factor, transforming growth factor-beta, fibronectin and antithrombin-1. Interactions between fibronectin and some syndecans can be modulated by the extracellular matrix protein tenascin-C.

Additional recommended knowledge

Daily Sensitivity Test

Don't let static charges disrupt your weighing accuracy

Recognize and detect the effects of electrostatic charges on your balance

Family members

The syndecan protein family is comprised of four members. Syndecans 1 and 3 and syndecans 2 and 4 making up separate subfamilies having arisen by gene duplication and divergent evolution from a single ancestral gene.^[1] The syndecan numbers reflect the order in which the cDNAs for each family member were cloned. All syndecans have an N-terminal signal peptide, an ectodomain, a single hydrophobic transmembrane domain, and a short C-terminal cytoplasmic domain.^[2] The ectodomains show the least amount of amino acid sequence conservation, no more than 10-20%, in contrast the transmembrane and cytoplasmic domains share around 60-70% amino acid sequence identity.^[3] The transmembrane domains contain an unusual alanine/glycine sequence motif while the cytoplasmic domain is essentially composed of two regions of conserved amino acid sequence (C1 and C2), separated by a central variable sequence of amino acids that is distinct for each family member (V).

References

1. ^ Carey, D. J. (1997). "Syndecans: multifunctional cell-surface co-receptors". Biochem. J. 327: 1-16. PMID 9355727.
2. ^ Bernfield M, Kokenyesi R. et al (1992). "Biology of syndecans: a family of transmembrane heparan sulfate proteoglycans". Annu. Rev. Cell. Biol. 8: 365-393. PMID 1335744.
3. ^ David, G. (1993). "Integral membrane heparan sulfate proteoglycans". FASEB. J. 7 (11): 1023-1030.