Tenascin

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Tenascins are proteins in the extracellular matrix, the support network around cells. They are common in developing embryos and also appear around healing wounds and in the supportive tissue of some cancers. There are four tenascin proteins: tenascin-C, -R, -X, and -W. Their basic structure includes 14 EGF-like repeats at the N-terminus and eight or more fibronectin-III domains, with variation by species and variant. Tenascin-C is the best studied. It has anti-adhesive properties, which can cause cells in culture to round up when added. One reason is that it binds to fibronectin and blocks fibronectin from interacting with syndecans on the cell surface. When tenascin-C is present in tumor stroma, it is often linked to a poorer prognosis.