This entry represents the hyaluronan synthase 2 (HAS2), which plays a role in hyaluronan/hyaluronic acid (HA) synthesis []. There are three different, but related hyaluronan synthases - HAS1, HAS2 and HAS3. They are multipass transmembrane enzymes, the active sites of which protrude from the inner face of the plasma membrane. HA is an unbranched disaccharide glucuronic acid/N-acetylglucosamine polymer and is one of the main components of the extracellular matrix []. High level of HA in humans is associated with cancer progression [, ]. In vertebrates, different HA polymer length can trigger different biological responses. High-molecular-mass HA represses mitogenic signalling and has anti-inflammatory properties, while low-molecular-mass HA promotes proliferation and inflammation [, ]. A study of the naked mole rat showed that HAS2 is overexpressed in naked mole rat fibroblasts, while the expression levels of HAS1 and HAS3 are similar between mouse, human and naked mole-rat cells []. HAS2 is responsible for the synthesis of the high-molecular-mass HA (HMM-HA), which triggers ECI (early contact inhibition) via the CD44 receptor and plays a key role in mediating the cancer resistance of the naked mole rat [].
