Fig. 1

CD44 protein and gene structure. a Four domains of CD44 glycoprotein are presented with correponding colors: ligand binding domain, variable domain, transmembrane domain, and cytoplasmic tail. b CD44 is encoded by 20 exons in mice but 19 exons in humans. Exon 6 coding for CD44 variant 1 (CD44v1) is lacking in humans. Green color exons are always expressed as a standard form of CD44 (CD44s), and up to nine exon variants can be inserted by alternative splicing. Full-length CD44, CD44s, CD44v3, CD44v6, and CD44v8-10 are shown schematically