Function
is a highly glycosylated multifunctional cell surface receptor that is involved in cell-cell interaction and maintenance of the extracellular matrix.[1] The primary ligand for CD44 is hyaluronan (HA), but it has also been found to interact with other molecules including osteopontin (OPN), collagens, and fibronectin. [2] CD44 is a single chain protein containing four distinct regions: the N-terminal HA binding Link domain[3], a flexible variable domain, a transmembrane domain, and an intracellular signaling domain.[4] The is an approximately 100 amino acid domain consisting of two antiparallel β-sheets, two α-helicies, and two disulfide bonds.[5] This domain is found in most HA binding proteins, including aggrecan, versican, brevican, and tumor necrosis factor-inducible gene 6.[6]
Evolutionary Conservation
of CD44 residues, as determined by ConSurfDB.
You may read the explanation
of the method and the full data available from
ConSurf.
Residues proximal to the HA binding site tend to be the most conserved across species while residues that fall outside of the cannonical Link domain are the most variable.
Isoforms
File:CD44 Isoforms.png
Substrate Binding
Cancer
