World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0003369095
Reproduction Date:

Title: Cd44  
Author: World Heritage Encyclopedia
Language: English
Subject: CD164, VE-cadherin, CD146, CD24, CD11c
Collection: Blood Antigen Systems, Clusters of Differentiation, Glycoproteins, Transfusion Medicine
Publisher: World Heritage Encyclopedia


CD44 molecule (Indian blood group)
PDB rendering based on 1poz.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols  ; CDW44; CSPG8; ECMR-III; HCELL; HUTCH-I; IN; LHR; MC56; MDU2; MDU3; MIC4; Pgp1
External IDs GeneCards:
RNA expression pattern
Species Human Mouse
RefSeq (mRNA)
RefSeq (protein)
Location (UCSC)
PubMed search

The CD44 antigen is a cell-surface glycoprotein involved in cell–cell interactions, cell adhesion and migration. In humans, the CD44 antigen is encoded by the CD44 gene on Chromosome 11.[1] CD44 has been referred to as HCAM (homing cell adhesion molecule), Pgp-1 (phagocytic glycoprotein-1), Hermes antigen, lymphocyte homing receptor, ECM-III, and HUTCH-1.


  • Tissue distribution and isoforms 1
  • Function 2
    • HCELL 2.1
  • Clinical significance 3
  • CD44 in cancer 4
  • Interactions 5
  • References 6
  • Further reading 7
  • External links 8

Tissue distribution and isoforms

CD44 is expressed in a large number of mammalian cell types. The 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.[2]


CD44 participates 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 can also interact with other ligands, such as osteopontin, collagens, and matrix metalloproteinases (MMPs). CD44 function is controlled by its posttranslational modifications. One critical modification involves discrete sialofucosylations rendering the selectin-binding glycoform of CD44 called HCELL (for Hematopoietic Cell E-selectin/L-selectin Ligand).[3] (see below)

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. Splice variants of CD44 on colon cancer cells display sialofucosylated HCELL glycoforms that serve as P-, L-, and E-selectin ligands and fibrin, but not fibrinogen, receptors under hemodynamic flow conditions pertinent to the process of cancer metastasis.[4][5]

CD44 gene transcription is at least in part activated by beta-catenin and Wnt signalling (also linked to tumour development).


The HCELL glycoform was originally discovered on human hematopoietic stem cells and leukemic blasts,[3][6][7][8] and was subsequently identified on cancer cells.[5][9][10][11][12] HCELL functions as a "bone homing receptor", directing migration of human hematopoietic stem cells and mesenchymal stem cells to bone marrow.[7] Ex vivo glycan engineering of the surface of live cells has been used to enforce HCELL expression on any cell that expresses CD44.[13] CD44 glycosylation also directly controls its binding capacity to fibrin and immobilized fibrinogen.[4][14]

Clinical significance

The protein is a determinant for the Indian blood group system.

  • 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[15] and has been seen as an indicator of increased survival time in epithelial ovarian cancer patients.[16]

Endometrial cells in women with endometriosis demonstrate increased expression of splice variants of CD44, and increased adherence to peritoneal cells.[17]

CD44 variant isoforms are also relevant to the progression of head and neck squamous cell carcinoma.[18][19]

Monoclonal antibodies against CD44 variants include bivatuzumab for v6.

CD44 in cancer

CD44 is a multistructural and multifunctional cell surface molecule involved in 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 these biological properties are essential to the physiological activities of normal cells, but they are also associated with the pathologic activities of cancer cells. Experiments in animals have shown that targeting of CD44 by antibodies, antisense oligonucleotides, and CD44-soluble proteins markedly reduces the malignant activities of various neoplasms, stressing the therapeutic potential of anti-CD44 agents. Furthermore, because alternative splicing and posttranslational modifications generate many different CD44 sequences, including, perhaps, tumor-specific sequences, the production of anti-CD44 tumor-specific agents may be a realistic therapeutic approach.[20] However, in many cancers (renal cancer and non-Hodgkin's lymphomas are exceptions), a high level of CD44 expression is not always associated with an unfavorable outcome. On the contrary, in some neoplasms CD44 upregulation is associated with a favorable outcome. Additionally, in many cases different research groups analyzing the same neoplastic disease reached contradictory conclusions regarding the correlation between CD44 expression and disease prognosis, possibly due to differences in methodology. These problems must be resolved before applying anti-CD44 therapy to human cancers.[21]


CD44 has been shown to interact with:


  1. ^ Spring FA, Dalchau R, Daniels GL, Mallinson G, Judson PA, Parsons SF, Fabre JW, Anstee DJ (May 1988). "The Ina and Inb blood group antigens are located on a glycoprotein of 80,000 MW (the CDw44 glycoprotein) whose expression is influenced by the In(Lu) gene". Immunology 64 (1): 37–43.  
  2. ^ Goodison S, Urquidi V, Tarin D (Aug 1999). "CD44 cell adhesion molecules". Molecular Pathology 52 (4): 189–96.  
  3. ^ a b Oxley SM, Sackstein R (Nov 1994). "Detection of an L-selectin ligand on a hematopoietic progenitor cell line". Blood 84 (10): 3299–306.  
  4. ^ a b c Alves CS, Burdick MM, Thomas SN, Pawar P, Konstantopoulos K (Apr 2008). "The dual role of CD44 as a functional P-selectin ligand and fibrin receptor in colon carcinoma cell adhesion". American Journal of Physiology. Cell Physiology 294 (4): C907–16.  
  5. ^ a b Hanley WD, Burdick MM, Konstantopoulos K, Sackstein R (Jul 2005). "CD44 on LS174T colon carcinoma cells possesses E-selectin ligand activity". Cancer Research 65 (13): 5812–7.  
  6. ^ Sackstein R, Dimitroff CJ (Oct 2000). "A hematopoietic cell L-selectin ligand that is distinct from PSGL-1 and displays N-glycan-dependent binding activity". Blood 96 (8): 2765–74.  
  7. ^ a b Sackstein R, Merzaban JS, Cain DW, Dagia NM, Spencer JA, Lin CP, Wohlgemuth R (Feb 2008). "Ex vivo glycan engineering of CD44 programs human multipotent mesenchymal stromal cell trafficking to bone". Nature Medicine 14 (2): 181–7.  
  8. ^ Dimitroff CJ, Lee JY, Rafii S, Fuhlbrigge RC, Sackstein R (Jun 2001). "CD44 is a major E-selectin ligand on human hematopoietic progenitor cells". The Journal of Cell Biology 153 (6): 1277–86.  
  9. ^ Burdick MM, Chu JT, Godar S, Sackstein R (May 2006). "HCELL is the major E- and L-selectin ligand expressed on LS174T colon carcinoma cells". The Journal of Biological Chemistry 281 (20): 13899–905.  
  10. ^ a b Hanley WD, Napier SL, Burdick MM, Schnaar RL, Sackstein R, Konstantopoulos K (Feb 2006). "Variant isoforms of CD44 are P- and L-selectin ligands on colon carcinoma cells". FASEB Journal 20 (2): 337–9.  
  11. ^ a b Napier SL, Healy ZR, Schnaar RL, Konstantopoulos K (Feb 2007). "Selectin ligand expression regulates the initial vascular interactions of colon carcinoma cells: the roles of CD44v and alternative sialofucosylated selectin ligands". The Journal of Biological Chemistry 282 (6): 3433–41.  
  12. ^ a b Thomas SN, Zhu F, Schnaar RL, Alves CS, Konstantopoulos K (Jun 2008). "Carcinoembryonic antigen and CD44 variant isoforms cooperate to mediate colon carcinoma cell adhesion to E- and L-selectin in shear flow". The Journal of Biological Chemistry 283 (23): 15647–55.  
  13. ^ Sackstein R (Jul 2009). "Glycosyltransferase-programmed stereosubstitution (GPS) to create HCELL: engineering a roadmap for cell migration". Immunological Reviews 230 (1): 51–74.  
  14. ^ a b Alves CS, Yakovlev S, Medved L, Konstantopoulos K (Jan 2009). "Biomolecular characterization of CD44-fibrin(ogen) binding: distinct molecular requirements mediate binding of standard and variant isoforms of CD44 to immobilized fibrin(ogen)". The Journal of Biological Chemistry 284 (2): 1177–89.  
  15. ^ Li F, Tiede B, Massagué J, Kang Y (Jan 2007). "Beyond tumorigenesis: cancer stem cells in metastasis". Cell Research 17 (1): 3–14.  
  16. ^ Sillanpää S, Anttila MA, Voutilainen K, Tammi RH, Tammi MI, Saarikoski SV, Kosma VM (Nov 2003). "CD44 expression indicates favorable prognosis in epithelial ovarian cancer". Clinical Cancer Research 9 (14): 5318–24.  
  17. ^ Griffith JS, Liu YG, Tekmal RR, Binkley PA, Holden AE, Schenken RS (Apr 2010). "Menstrual endometrial cells from women with endometriosis demonstrate increased adherence to peritoneal cells and increased expression of CD44 splice variants". Fertility and Sterility 93 (6): 1745–9.  
  18. ^ Wang SJ, Wong G, de Heer AM, Xia W, Bourguignon LY (Aug 2009). "CD44 variant isoforms in head and neck squamous cell carcinoma progression". The Laryngoscope 119 (8): 1518–30.  
  19. ^ Assimakopoulos D, Kolettas E, Patrikakos G, Evangelou A (Oct 2002). "The role of CD44 in the development and prognosis of head and neck squamous cell carcinomas". Histology and Histopathology 17 (4): 1269–81.  
  20. ^ Eibl RH, Pietsch T, Moll J, Skroch-Angel P, Heider KH, von Ammon K, Wiestler OD, Ponta H, Kleihues P, Herrlich P (Dec 1995). "Expression of variant CD44 epitopes in human astrocytic brain tumors". Journal of Neuro-Oncology 26 (3): 165–70.  
  21. ^ Naor D, Nedvetzki S, Golan I, Melnik L, Faitelson Y (Nov 2002). "CD44 in cancer". Critical Reviews in Clinical Laboratory Sciences 39 (6): 527–79.  
  22. ^ Bourguignon LY, Singleton PA, Zhu H, Diedrich F (Aug 2003). "Hyaluronan-mediated CD44 interaction with RhoGEF and Rho kinase promotes Grb2-associated binder-1 phosphorylation and phosphatidylinositol 3-kinase signaling leading to cytokine (macrophage-colony stimulating factor) production and breast tumor progression". The Journal of Biological Chemistry 278 (32): 29420–34.  
  23. ^ Chen X, Khajeh JA, Ju JH, Gupta YK, Stanley CB, Do C, Heller WT, Aggarwal AK, Callaway DJ, Bu Z (Mar 2015). "Phosphatidylinositol 4,5-bisphosphate clusters the cell adhesion molecule CD44 and assembles a specific CD44-Ezrin heterocomplex, as revealed by small angle neutron scattering". The Journal of Biological Chemistry 290 (10): 6639–52.  
  24. ^ Jalkanen S, Jalkanen M (Feb 1992). "Lymphocyte CD44 binds the COOH-terminal heparin-binding domain of fibronectin". The Journal of Cell Biology 116 (3): 817–25.  
  25. ^ a b Ilangumaran S, Briol A, Hoessli DC (May 1998). "CD44 selectively associates with active Src family protein tyrosine kinases Lck and Fyn in glycosphingolipid-rich plasma membrane domains of human peripheral blood lymphocytes". Blood 91 (10): 3901–8.  
  26. ^ Zohar R, Suzuki N, Suzuki K, Arora P, Glogauer M, McCulloch CA, Sodek J (Jul 2000). "Intracellular osteopontin is an integral component of the CD44-ERM complex involved in cell migration". Journal of Cellular Physiology 184 (1): 118–30.  
  27. ^ Taher TE, Smit L, Griffioen AW, Schilder-Tol EJ, Borst J, Pals ST (Feb 1996). "Signaling through CD44 is mediated by tyrosine kinases. Association with p56lck in T lymphocytes". The Journal of Biological Chemistry 271 (5): 2863–7.  
  28. ^ Bourguignon LY, Zhu H, Shao L, Chen YW (Mar 2001). "CD44 interaction with c-Src kinase promotes cortactin-mediated cytoskeleton function and hyaluronic acid-dependent ovarian tumor cell migration". The Journal of Biological Chemistry 276 (10): 7327–36.  

Further reading

  • Sackstein R (Jul 2011). "The biology of CD44 and HCELL in hematopoiesis: the 'step 2-bypass pathway' and other emerging perspectives". Current Opinion in Hematology 18 (4): 239–48.  
  • Sackstein R (Jul 2009). "Glycosyltransferase-programmed stereosubstitution (GPS) to create HCELL: engineering a roadmap for cell migration". Immunological Reviews 230 (1): 51–74.  
  • Sackstein R (May 2004). "The bone marrow is akin to skin: HCELL and the biology of hematopoietic stem cell homing". The Journal of Investigative Dermatology 122 (5): 1061–9.  
  • Konstantopoulos K, Thomas SN (2009). "Cancer cells in transit: the vascular interactions of tumor cells". Annual Review of Biomedical Engineering 11: 177–202.  
  • Günthert U (1994). "CD44: a multitude of isoforms with diverse functions". Current Topics in Microbiology and Immunology 184: 47–63.  
  • Yasuda M, Nakano K, Yasumoto K, Tanaka Y (2003). "CD44: functional relevance to inflammation and malignancy". Histology and Histopathology 17 (3): 945–50.  
  • Sun CX, Robb VA, Gutmann DH (Nov 2002). "Protein 4.1 tumor suppressors: getting a FERM grip on growth regulation". Journal of Cell Science 115 (Pt 21): 3991–4000.  
  • Ponta H, Sherman L, Herrlich PA (Jan 2003). "CD44: from adhesion molecules to signalling regulators". Nature Reviews. Molecular Cell Biology 4 (1): 33–45.  
  • Martin TA, Harrison G, Mansel RE, Jiang WG (May 2003). "The role of the CD44/ezrin complex in cancer metastasis". Critical Reviews in Oncology/Hematology 46 (2): 165–86.  

External links

  • Indian blood group system at BGMUT Blood Group Antigen Gene Mutation Database at NCBI, NIH
  • Articles at IHOP.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.