Figure 2.

Structure, binding domains and interactions of CD44. The CD44 protein is composed of an extracellular link domain where the variant isoform is located with 292-300 a.a, a stalk-like region in the extracellular module stabilized by disulphide bonding of 6 cysteine residues and contains binding sites for hyalurona hyaluronan-binding motifs (HA) as well as facilitate its interactions with matrix metalloproteinases (MMPs) and other growth factors/growth factor receptors. Close to The transmembrane region (TM), the variant exon products (Variable region) are inserted. The cytoplasmic tail (CP) and Transmembrane domain undergo both phosphorylation on cysteine and serine residues and palmitoylation, respectively with crucial binding motifs for Ankyrin, ErbB2, epidermal growth factor receptor-2; ERM/Merlin, ezrin/radixin/moesin; disulphide bonds, PI3K, phosphoinositide 3-kinase, cytoskeletal linker proteins and SRC kinases.