Syndecan Functional Domains. The syndecan core proteins display a high degree of conservation across species and across family members within their transmembrane and cytoplasmic domains, implying that some functional redundancy may exist among the family members. In contrast, the ectodomains of the syndecan core proteins are highly divergent both in size and sequence, indicating that this domain may confer separate and unique functions to each individual family member. Specific functions for the ectodomain of the syndecan core proteins are almost wholly unknown.
Beauvais and Rapraeger Reproductive Biology and Endocrinology 2004 2:3 doi:10.1186/1477-7827-2-3