| Product Use |
Monoclonal CD44 antibody specific for Human CD44 for use in ELISA, Flow Cytometry, Immunohistochemistry and Western Blot. |
| Biological Significance |
CD44 is a 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. Interacts with PKN2. Interacts with HA, as well as other glycosaminoglycans, collagen, laminin, and fibronectin via its N-terminal segment. Interacts with ANK, the ERM proteins (VIL2, RDX and MSN), and NF2 via its C-terminal segment. Isoform 10 (epithelial isoform) is expressed by cells of epithelium and highly expressed by carcinomas. Expression is repressed in neuroblastoma cells.
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| Expression |
CD44 is expressed in a large number of mammalian cell types. Standard isoform, designated CD44s, comprising exons 1–5 and 16–20 is expressed in most cell types. CD44 splice variants containing variable exons are designated CD44v. Some epithelial cells also express a larger isoform (CD44E), which includes exons v8–10. CD44 is located in the Golgi apparatus and on the cell surface integral to plasma membrane as well as the cytoplasm. |
| Implications in Disease |
Variations in CD44 are reported as cell surface markers for some breast and prostate cancer stem cells. CD44 expression is commonly used as a marker for breast CSCs and is used to sort breast cancer cells into a population enriched in cells with stem-like characteristics. CD44 has also been used as an indicator of increased survival time in epithelial ovarian cancer patients. CD44 is associated with cell proliferation, cell differentiation, cell migration, angiogenesis, presentation of cytokines, chemokines, and growth factors to the corresponding receptors, and docking of proteases at the cell membrane, as well as in signaling for cell survival, all attributes associated with the pathologic activities of cancer cells. |
| Sequence Information |
CD44 is a member of theCD44 (H-CAM) family of cell surface glycoproteins. CD44 contains 4 Hyaluronan binding sites at amino acids 41, 78, 79 and 105. |
| Post-Translational Modifications |
CD44 interacts with ezrin, radixin and moesin (ERM), linking the actin cytoskeleton to the plasma membrane and the ECM. CD44 is constitutively phosphorylated at Ser325 in resting cells. Activation of PKC results in phosphorylation of Ser291, dephosphorylation of Ser325, disassociation of ezrin from CD44, and directional motility. |
| Database Links |
Entrez Gene: 960 Human, Omim: 107269 Human, SwissProt: P16070 Human, Unigene: 502328 Human |