Catalyzes the addition of GlcNAc or GlcUA monosaccharides to the nascent hyaluronan polymer. Therefore, it is essential to hyaluronan synthesis a major component of most extracellular matrices that has a structural role in tissues architectures and regulates cell adhesion, migration and differentiation. This is one of three isoenzymes responsible for cellular hyaluronan synthesis.
Cell membrane ; Multi-pass membrane protein . Golgi apparatus membrane ; Multi-pass membrane protein. Golgi apparatus, trans-Golgi network membrane ; Multi-pass membrane protein . Early endosome . Travels from endoplasmic reticulum (ER), Golgi to plasma membrane (PubMed:26883802). Actives only when present in plasma membrane (By similarity). O-GlcNAcylation controls its membrane localization (PubMed:26883802). A rapid recycling of HAS3 between plasma membrane and endosomes is controlled by the cytosolic levels of UDP-GlcUA and UDP-GlcNAc (PubMed:26883802). .