O-glycosylation is essential for intracellular targeting of synaptotagmins I and II in non-neuronal specialized secretory cells
Author:
Atiya-Nasagi Yafit1, Cohen Hila1, Medalia Ora1, Fukudan Mitsunori2, Sagi-Eisenberg Ronit1
Affiliation:
1. Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel 2. Fukuda Initiative Research Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
Abstract
We have examined the trafficking of synaptotagmin (Syt) I and II in the mast cell line rat basophilic leukemia (RBL-2H3). 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.
Publisher
The Company of Biologists
Reference42 articles.
1. Alfalah, M., Jacob, R., Preuss, U., Zimmer, K. P., Naim, H. and Naim, H. Y. (1999). O-linked glycans mediate apical sorting of human intestinal sucrose-isomaltase through association with lipid rafts. Curr. Biol.9, 593-596. 2. Baram, D., Linial, M., Mekori, Y. A. and Sagi-Eisenberg, R. (1998). Ca2+-dependent exocytosis in mast cells is stimulated by the Ca2+ sensor, synaptotagmin I. J. Immunol.161, 5120-5123. 3. Baram, D., Adachi, R., Medalia, O., Tuvim, M., Dickey, B. F., Mekori, Y. A. and Sagi-Eisenberg, R. (1999). Synaptotagmin II negatively regulates Ca2+-triggered exocytosis of lysosomes in mast cells. J. Exp. Med.189, 1649-1658. 4. Barzilay, E., Ben-Califa, N., Supino-Rosin, L., Kashman, Y., Hirschberg, K., Elazar, Z. and Neumann, D. (2004). Geldanamycin-associated inhibition of intracellular trafficking is attributed to a co-purified activity. J. Biol. Chem.279, 6847-6852. 5. Bonifacino, J. S., Yuan, L. and Sandoval, I. V. (1989). Internalization and recycling to serotonin-containing granules of the 80K integral membrane protein exposed on the surface of secreting rat basophilic leukaemia cells. J. Cell Sci.92, 701-712.
Cited by
14 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|