Human CD44 Protein, hFc tag

The CD44 antigen is a cell-surface glycoprotein involved in a wide variety of cellular functions including lymphocyte activation, recirculation and homing, hematopoiesis, and tumor metastasis. CD44 is a receptor for hyaluronic acid and internalizes metals bound to hyaluronic acid and can also interact with other ligands, such as osteopontin, collagens, and matrix metalloproteinases (MMPs). CD44 function is controlled by its posttranslational modifications. Transcripts for this gene undergo complex alternative splicing that results in many functionally distinct isoforms. CD44, along with CD25, is used to track early T cell development in the thymus. CD44 expression is an indicative marker for effector-memory T-cells. Memory cell proliferation (activation) can also be assayed in vitro with CFSE chemical tagging. In addition, variations in CD44 are reported as cell surface markers for some breast and prostate cancer stem cells. In breast cancer research CD44+/CD24- 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 and has been seen as an indicator of increased survival time in epithelial ovarian cancer patients. Endometrial cells in women with endometriosis demonstrate increased expression of splice variants of CD44, and increased adherence to peritoneal cells. CD44 variant isoforms are also relevant to the progression of head and neck squamous cell carcinoma.