2i83
hyaluronan-binding domain of CD44 in its ligand-bound form
Structural highlights
FunctionCD44_HUMAN Receptor for hyaluronic acid (HA). Mediates cell-cell and cell-matrix interactions through its affinity for HA, and possibly also through its affinity for other ligands such as osteopontin, collagens, and matrix metalloproteinases (MMPs). Adhesion with HA plays an important role in cell migration, tumor growth and progression. Also involved in lymphocyte activation, recirculation and homing, and in hematopoiesis. Altered expression or dysfunction causes numerous pathogenic phenotypes. Great protein heterogeneity due to numerous alternative splicing and post-translational modification events. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCD44, a major cell surface receptor for hyaluronan (HA), contains a functional domain responsible for HA binding at its N terminus (residues 21-178). Accumulating evidence indicates that proteolytic cleavage of CD44 in its extracellular region (residues 21-268) leads to enhanced tumor cell migration and invasion. Hence, understanding the mechanisms underlying the CD44 proteolytic cleavage is important for understanding the mechanism of CD44-mediated tumor progression. Here we present the NMR structure of the HA-binding domain of CD44 in its HA-bound state. The structure is composed of the Link module (residues 32-124) and an extended lobe (residues 21-31 and 125-152). Interestingly, a comparison of its unbound and HA-bound structures revealed that rearrangement of the beta-strands in the extended lobe (residues 143-148) and disorder of the structure in the following C-terminal region (residues 153-169) occurred upon HA binding, which is consistent with the results of trypsin proteolysis studies of the CD44 HA-binding domain. The order-to-disorder transition of the C-terminal region by HA binding may be involved in the CD44-mediated cell migration. Ligand-induced structural changes of the CD44 hyaluronan-binding domain revealed by NMR.,Takeda M, Ogino S, Umemoto R, Sakakura M, Kajiwara M, Sugahara KN, Hayasaka H, Miyasaka M, Terasawa H, Shimada I J Biol Chem. 2006 Dec 29;281(52):40089-95. Epub 2006 Nov 2. PMID:17085435[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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