sentences:  The ectodomains show the least amount of amino acid sequence conservation, not more than 10–20%; in contrast, the transmembrane and cytoplasmic domains share approximately 60–70% amino acid sequence identity.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).In mammalian cells, syndecans are expressed by unique genes located on different chromosomes.