Heparan sulfate 3-O-sulfotransferase 2 (HS3ST2) displays an unexpected subcellular localization in the plasma membrane

• Published in: Biochimica et biophysica acta Vol. 1862; no. 7; pp. 1644 - 1655
• Main Authors: Delos, Maxime, Foulquier, François, Hellec, Charles, Vicogne, Dorothée, Fifre, Alexandre, Carpentier, Mathieu, Papy-Garcia, Dulce, Allain, Fabrice, Denys, Agnès
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2018; Elsevier
• Series: Biochimica et Biophysica Acta (BBA) - General Subjects
• Subjects: Amidohydrolases - analysis; Amidohydrolases - genetics; Cell Membrane - enzymology; Cells, Cultured; Chemical Sciences; Glycobiology; Golgi Apparatus - enzymology; HEK293 Cells; HeLa Cells; Heparan sulfate; Humans; Isoenzymes - analysis; Macrophages - enzymology; Membrane Proteins - analysis; Membrane Proteins - genetics; Microscopy, Fluorescence; Monocytes - cytology; or physical chemistry; Proteoglycan; Real-Time Polymerase Chain Reaction; RNA, Small Interfering - genetics; Subcellular Fractions - enzymology; Subcellular localization; Sulfotransferase; Sulfotransferases - analysis; Sulfotransferases - genetics; Syndecan-2 - analysis; Theoretical and; PBS; Heparan sulfate; Proteoglycan; HS2ST, HS3ST, HS6ST; TBS; siRNA; HPRT; HS; ER; BSA; GlcN; GlcUA; HSV-1; IdoUA; NDST; Glycobiology; Sulfotransferase; FCS; Subcellular localization; GlcNS; EXTL3; RFP; WT
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2018.04.013

Heparan sulfate (HS) 3-O-sulfation can be catalysed by seven 3-O-sulfotransferases (HS3STs) in humans, still it is the rarest modification in HS and its biological function is yet misunderstood. HS3ST2 and HS3ST3B exhibit the same activity in vitro. They are however differently expressed in macrophages depending on cell environment, which suggests that they may be involved in distinct cellular processes. Here, we hypothesized that both isozymes might also display distinct subcellular localizations. The subcellular distribution of HS3ST2 and HS3ST3B was analysed by using overexpression systems in HeLa cells. The localization of endogenous HS3ST2 was confirmed by immunostaining in primary macrophages. We found that HS3ST3B was only localized in the Golgi apparatus and no difference between full-length enzyme and truncated construct depleted of its catalytic domain was observed. In contrast, HS3ST2 was clearly visualized at the plasma membrane. Its truncated form remained in the Golgi apparatus, meaning that the catalytic domain might support correct addressing of HS3ST2 to cell surface. Moreover, we found a partial co-localization of HS3ST2 with syndecan-2 in HeLa cells and primary macrophages. Silencing the expression of this proteoglycan altered the localization of HS3ST2, which suggests that syndecan-2 is required to address the isozyme outside of the Golgi apparatus. We demonstrated that HS3ST3B is a Golgi-resident isozyme, while HS3ST2 is addressed to the plasma membrane with syndecan-2. The membrane localization of HS3ST2 suggests that this enzyme may participate in discrete processes that occur at the cell surface. •Heparan sulfate 3-O-sulfotransferase 3B (HS3ST3B) is a Golgi-resident enzyme.•Unlike HS3ST3B, HS3ST2 is expressed in the vicinity of the plasma membrane.•HS3ST2 co-localizes with the proteoglycan syndecan-2 in the plasma membrane.•Syndecan-2 is required to address HS3ST2 outside of the Golgi apparatus.