CD44 encodes a protein that is involved in cell-cell interactions, cell adhesion, and migration. It interacts with other ligands, such as osteopontin, collagens, and matrix metalloproteinases (MMPs) (R).

It can be used as a marker for memory cells as well as breast, prostate, and ovarian cancer cells (R). High levels of CD44 expression may lead to some types of cancer (R). 

     From NCBI Gene: INDIAN BLOOD GROUP SYSTEM

     From NCBI Gene: The protein encoded by this gene is a cell-surface glycoprotein involved in cell-cell interactions, cell adhesion and migration. It is a receptor for hyaluronic acid (HA) and can also interact with other ligands, such as osteopontin, collagens, and matrix metalloproteinases (MMPs). This protein participates in a wide variety of cellular functions including lymphocyte activation, recirculation and homing, hematopoiesis, and tumor metastasis. Transcripts for this gene undergo complex alternative splicing that results in many functionally distinct isoforms, however, the full length nature of some of these variants has not been determined. Alternative splicing is the basis for the structural and functional diversity of this protein, and may be related to tumor metastasis. [provided by RefSeq, Jul 2008] From UniProt: 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. In cancer cells, may play an important role in invadopodia formation. 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. Receptor for LGALS9; the interaction enhances binding of SMAD3 to the FOXP3 promoter, leading to up-regulation of FOXP3 expression and increased induced regulatory T (iTreg) cell stability and suppressive function.

The following transcription factors affect gene expression:

• NF-kappaB
• PPAR-gamma1
• PPAR-gamma2
• Egr-1
• AP-1
• c-Jun
• NF-kappaB1
• c-Fos

Tissue specificity:

Isoform 10 (epithelial isoform) is expressed by cells of epithelium and highly expressed by carcinomas. Expression is repressed in neuroblastoma cells.

Molecular Function:

• Collagen Binding
• Hyaluronic Acid Binding

Biological Processes:

• Cartilage Development
• Cell-Matrix Adhesion
• Cellular Response To Fibroblast Growth Factor Stimulus
• Extracellular Matrix Disassembly
• Extracellular Matrix Organization
• Hyaluronan Catabolic Process
• Interferon-Gamma-Mediated Signaling Pathway
• Leukocyte Migration
• Monocyte Aggregation
• Negative Regulation Of Apoptotic Process
• Negative Regulation Of Cysteine-Type Endopeptidase Activity Involved In Apoptotic Process
• Negative Regulation Of Dna Damage Response, Signal Transduction By P53 Class Mediator
• Negative Regulation Of Intrinsic Apoptotic Signaling Pathway In Response To Dna Damage By P53 Class Mediator
• Positive Regulation Of Erk1 And Erk2 Cascade
• Positive Regulation Of Heterotypic Cell-Cell Adhesion
• Positive Regulation Of Monocyte Aggregation
• Positive Regulation Of Peptidyl-Serine Phosphorylation
• Positive Regulation Of Peptidyl-Tyrosine Phosphorylation
• Single Organismal Cell-Cell Adhesion

Drug Bank:

• Hyaluronic Acid