The extended cytoplasmic tail of the human B4GALNT2 is critical for its Golgi targeting and post‐Golgi sorting. (31st August 2018)

• Record Type: Journal Article
• Authors: Groux‐Degroote, Sophie; Schulz, Céline; Cogez, Virginie; Noël, Maxence; Portier, Lucie; Vicogne, Dorothée; Solorzano, Carlos; Dall'Olio, Fabio; Steenackers, Agata; Mortuaire, Marlène; Gonzalez‐Pisfil, Mariano; Henry, Mélanie; Foulquier, François; Héliot, Laurent; Harduin‐Lepers, Anne
• Is Part Of: FEBS journal. Volume 285:Number 18(2018)
• Page Start: 3442
• Page End: 3463
• Publication Date: 2018-08-31
• Subjects: B4GALNT2 -- cytoplasmic tail -- glycosyltransferase localization -- Golgi -- vesicles; Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pathology, Molecular -- Periodicals; 572
• DOI: 10.1111/febs.14621
• Languages: English
• ISSNs: 1742-464X

Abstract

Abstract : The Sd a /Cad antigen reported on glycoconjugates of human tissues has an increasingly recognized wide impact on the physio‐pathology of different biological systems. The last step of its biosynthesis relies on the enzymatic activity of the β1, 4‐N‐acetylgalactosaminyltransferase‐II (B4GALNT2), which shows the highest expression level in healthy colon. Previous studies reported the occurrence in human colonic cells of two B4GALNT2 protein isoforms that differ in the length of their cytoplasmic tail, the long isoform showing an extended 66‐amino acid tail. We examined here, the subcellular distribution of the two B4GALNT2 protein isoforms in stably transfected colonic LS174T cells and in transiently transfected HeLa cells using fluorescence microscopy. While a similar subcellular distribution at the trans ‐Golgi cisternae level was observed for the two isoforms, our study pointed to an atypical subcellular localization of the long B4GALNT2 isoform into dynamic vesicles. We demonstrated a critical role of its extended cytoplasmic tail for its Golgi targeting and post‐Golgi sorting and highlighted the existence of a newly described post‐Golgi sorting signal as well as a previously undescribed fate of a Golgi glycosyltransferase. Database: The proteins β1, 4GalNAcT II, β1, 4‐GalT1, FucT I, FucT VI and ST3Gal IV are noted B4GALNT2, B4GALT1, FUT1, FUT6 and ST3GAL4, whereas the corresponding human genes are noted B4GALNT2, B4GALT1, FUT1, FUT6 and ST3GAL4 according to the HUGO nomenclature. Abstract : The two proteins arising from the human B4GALNT2 gene differ only in the length of their cytoplasmic tail. The long B4GALNT2 isoform shows an unusual extended 66‐amino acid cytoplasmic tail determining a previously undescribed fate of a Golgi glycosyltransferase. Strong molecular signals were identified in the long isoform cytoplasmic tail which are critical for its Golgi targeting and post‐Golgi sorting.