Hyaluronan synthase

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Hyaluronan synthase
EC number2.4.1.212
CAS number39346-43-5
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum

Hyaluronan synthases (HAS) are membrane-bound enzymes which use UDP-α-N-acetyl-D-glucosamine and UDP-α-D-glucuronate as substrates to produce the glycosaminoglycan hyaluronan at the cell surface and extrude it through the membrane into the extracellular space.


There are three mammalian hyaluronan synthases described to date - HAS1, HAS2 and HAS3. Each of these isoforms resides at a different chromosome location[1] and has been cloned.[2] Two of the main differences between the isoforms are the chain length of the hyaluronan molecules that they produce and the ease with which they can be released from the cell surface.[3][4] When mammalian cells are stimulated by changes in their immediate environment (cytokines, extracellular matrix proximities), the HAS isoforms respond differently and appear to be under different control mechanisms.

During the development of the embryo, each isoform is uniquely expressed, both spatially and temporally.

  • HAS2 is probably the most important synthase at this time as mice lacking the ability to express HAS2 (knock-out mice) die at mid-gestation,[5]
  • HAS1 or HAS3 knock-out mice show no effect on foetal development.[6]

Role in Cancer Metastasis[edit]

HAS can play roles in all of the stages of cancer metastasis. By producing anti-adhesive HA, HAS can allow tumor cells to release from the primary tumor mass and if HA associates with receptors such as CD44, the activation of Rho GTPases can promote EMT of the cancer cells. During the processes of intravasation or extravasation, the interaction of HAS produced HA with receptors such as CD44 or RHAMM promote the cell changes that allow for the cancer cells to infiltrate the vascular or lymphatic systems. While traveling in these systems, HA produced by HAS protects the cancer cell from physical damage. Finally, in the formation of a metastatic lesion, HAS produces HA to allow the cancer cell to interact with native cells at the secondary site and to produce a tumor for itself.[7]

Increased HA production by cancer cells increases invasive capacity. HA's interaction with CD44 activates focal adhesion kinase (FAK), an important molecule in the process of cell motility by coordinating dissolution of the focal adhesions at the leading edge of the cell and formation at the lagging edge.[8] Another signaling pathway activated by HA's interaction with CD44 is the Akt pathway which leads to expression of osteopontin, a molecule which can stimulate cell migration.[9] The HA produced by HAS also has been suggested to protect the cancer cell from physical damage while in the circulatory or lymphatic systems. This role of HA has been shown in other cell types, but has not yet been researched in cancer cells.[10] The HA produced by HAS up-regulates secretion of various MMPs, proteolytic enzymes that are involved in many stages of the metastatic cascade.[11] Research has shown that the different HASs may impact the metastatic steps in different ways based on the molecular weight and amount of HA they produce.


  1. ^ Spicer AP, Seldin MF, Olsen AS, Brown N, Wells DE, Doggett NA, Itano N, Kimata K, Inazawa J, McDonald JA (1997). "Chromosomal localization of the human and mouse hyaluronan synthase genes". Genomics. 41 (3): 493–7. doi:10.1006/geno.1997.4696. PMID 9169154.
  2. ^ Itano N, Kimata K (2002). "Mammalian hyaluronan synthases". IUBMB Life. 54 (4): 195–9. doi:10.1080/15216540214929. PMID 12512858.
  3. ^ Itano N, Sawai T, Yoshida M, Lenas P, Yamada Y, Imagawa M, Shinomura T, Hamaguchi M, Yoshida Y, Ohnuki Y, Miyauchi S, Spicer AP, McDonald JA, Kimata K (1999). "Three isoforms of mammalian hyaluronan synthases have distinct enzymatic properties". The Journal of Biological Chemistry. 274 (35): 25085–92. doi:10.1074/jbc.274.35.25085. PMID 10455188.
  4. ^ Stern R, Asari AA, Sugahara KN (2006). "Hyaluronan fragments: an information-rich system". European Journal of Cell Biology. 85 (8): 699–715. doi:10.1016/j.ejcb.2006.05.009. PMID 16822580.
  5. ^ Camenisch TD, Spicer AP, Brehm-Gibson T, Biesterfeldt J, Augustine ML, Calabro A, Kubalak S, Klewer SE, McDonald JA (2000). "Disruption of hyaluronan synthase-2 abrogates normal cardiac morphogenesis and hyaluronan-mediated transformation of epithelium to mesenchyme". The Journal of Clinical Investigation. 106 (3): 349–60. doi:10.1172/JCI10272. PMC 314332. PMID 10930438.
  6. ^ Bai KJ, Spicer AP, Mascarenhas MM, Yu L, Ochoa CD, Garg HG, Quinn DA (2005). "The role of hyaluronan synthase 3 in ventilator-induced lung injury". American Journal of Respiratory and Critical Care Medicine. 172 (1): 92–8. doi:10.1164/rccm.200405-652OC. PMC 2718450. PMID 15790861.
  7. ^ Bharadwaj AG, Kovar JL, Loughman E, Elowsky C, Oakley GG, Simpson MA (2009). "Spontaneous metastasis of prostate cancer is promoted by excess hyaluronan synthesis and processing". The American Journal of Pathology. 174 (3): 1027–36. doi:10.2353/ajpath.2009.080501. PMC 2665762. PMID 19218337.
  8. ^ Fujita Y, Kitagawa M, Nakamura S, Azuma K, Ishii G, Higashi M, Kishi H, Hiwasa T, Koda K, Nakajima N, Harigaya K (2002). "CD44 signaling through focal adhesion kinase and its anti-apoptotic effect". FEBS Letters. 528 (1–3): 101–8. doi:10.1016/S0014-5793(02)03262-3. PMID 12297287.
  9. ^ Park JB, Kwak HJ, Lee SH (2008). "Role of hyaluronan in glioma invasion". Cell Adhesion & Migration. 2 (3): 202–7. doi:10.4161/cam.2.3.6320. PMC 2634087. PMID 19262113.
  10. ^ Jiang D, Liang J, Fan J, Yu S, Chen S, Luo Y, Prestwich GD, Mascarenhas MM, Garg HG, Quinn DA, Homer RJ, Goldstein DR, Bucala R, Lee PJ, Medzhitov R, Noble PW (2005). "Regulation of lung injury and repair by Toll-like receptors and hyaluronan". Nature Medicine. 11 (11): 1173–9. doi:10.1038/nm1315. PMID 16244651.
  11. ^ Dunn KM, Lee PK, Wilson CM, Iida J, Wasiluk KR, Hugger M, McCarthy JB (2009). "Inhibition of hyaluronan synthases decreases matrix metalloproteinase-7 (MMP-7) expression and activity". Surgery. 145 (3): 322–9. doi:10.1016/j.surg.2008.11.008. PMID 19231585.

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