About SDC / Syndecan:
Syndecans are proteins that are believed to act as coreceptors, particularly for G protein-coupled receptors.
It is thought that these core proteins carry three to five heparan sulfate and chondroitin sulfate chains. There are four members of the Syndecan family, with 1 and 3, and 2 and 4 making up subfamilies. This happened by gene duplication and changing course of evolution from a single ancestral gene.
All syndecans have an N-terminal signal peptide, an ectodomain, a short C-terminal cytoplasmic domain and a single hydrophobic transmembrane domain. They are anchored to plasma membrane through a 24/25 amino acid hydrophopic transmembrane domain.
Glycosaminoglycans help the interaction of syndecans with extracellular ligands. The glycosaminoglycans have differen structures to accommodate the needs of the region, depending on the localization of the syndecan. From here, the syndecans are known to form homologous oligomers that are important for their future functions.
The four categories of functions of a syndecan are as follows:
●Growth factor receptor activation
●Tumor suppression and progressions through the prevention of cellular profileration of tumor cell lines.
They are under the class of proteoglycans which mean they can interact with a wide range of ligands. This includes things like fibroblast growth factors, transforming growth factor-beta fibronectin and vascular endothelial growth factor. Interactions that happen between fibronectin and some syndecans can be modulated by the extracellular matrix protein tenascin C.