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Fig. 2 | Cellular & Molecular Biology Letters

Fig. 2

From: Specific functions of Exostosin-like 3 (EXTL3) gene products

Fig. 2

Schematic representation of human EXT family members. All are single-pass transmembrane proteins with a type II topology. They have short cytoplasmic, transmembrane (TM) and long Golgi luminal regions. Apart from EXTL2, two predicted glycosyltransferase domains belonging to glycosyl transferase family 47 (GT47) and GT64 are present. The former and latter are presumed to exhibit the enzymatic activities of GlcAT-II and GlcNAcT-II, respectively. EXTL2 is the shortest among the EXT family members, and only has the GT64 domain in the luminal region. Although EXTL3 exhibits GlcNAcT-I and GlcNAcT-II activities, but not GlcAT-II activity, it currently remains unclear whether the GT47 domain exhibits GlcNAcT activities. DXD (Asp-X-Asp) motifs in amino acid sequences are shown as asterisks, which are important for glycosyltransferases to interact with a Mn2+ cofactor that stabilizes binding of the diphosphate moiety of the UDP-sugars substrate. Arrowheads indicate the sites of mutations found in human genetic diseases (see Table 2)

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