O-glycosylation is essential for intracellular targeting of synaptotagmins I and II in non-neuronal specialized secretory cells

Yafit Atiya-Nasagi, Hila Cohen, Ora Medalia, Mitsunori Fukuda, Ronit Sagi-Eisenberg

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

We have examined the trafficking of synaptotagmin (Syt) I and II in the mast cell line rat basophilic leukemia (RBL2H3). We demonstrate that both Syt I and Syt II travel through the plasma membrane and require endocytosis to reach their final intracellular localization. However, N- or C-terminal tagging of Syt II, but not of Syt I, prevents its internalization, trapping the tagged protein at the plasma membrane. Furthermore, a chimeric protein comprising a tagged luminal domain of Syt II fused with the remaining domains of Syt I also localizes to the plasma membrane, whereas a chimera consisting of tagged luminal domain of Syt I fused with Syt II colocalizes with Syt I on secretory granules. We also show that endocytosis of both Syt I and Syt II is strictly dependent on O-glycosylation processing, whereby O-glycosylation mutants of either protein fail to internalize and remain at the plasma membrane. Our results indicate that the luminal domains of Syt I and Syt II govern their internalization capacity from the plasma membrane and identify O-glycosylation as playing a crucial role in Syt trafficking in non-neuronal secretory cells.

Original languageEnglish
Pages (from-to)1363-1372
Number of pages10
JournalJournal of cell science
Volume118
Issue number7
DOIs
Publication statusPublished - 2005 Apr 1

Keywords

  • Glycosylation
  • RBL-2H3
  • Sorting
  • Synaptotagmin

ASJC Scopus subject areas

  • Cell Biology

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