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VIP36 localisation to the early secretory pathway
J Füllekrug1, P Scheiffele, K Simons
1Cell Biology, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, D-69117 Heidelberg, Germany.
Journal of Cell Science
|August 13, 1999
Summary
VIP36, an intracellular lectin, resides in the early secretory pathway of epithelial cells. Its retention capacity is limited, and it cycles between the Golgi apparatus and ER-Golgi intermediate compartments.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- VIP36 is an integral membrane protein and intracellular lectin.
- Previous studies suggested VIP36 is involved in post-Golgi trafficking.
- Its localization in epithelial cells (MDCK and Vero) was not fully characterized.
Purpose of the Study:
- To investigate the localization and trafficking of endogenous VIP36 in epithelial cells.
- To understand the role of VIP36 in the early secretory pathway.
- To determine if VIP36 retention is saturable.
Main Methods:
- High-resolution confocal microscopy was used to visualize VIP36 localization.
- Colocalization studies with Golgi markers, coatomer, ERGIC-53, and anterograde cargo were performed.
- The effect of brefeldin A treatment on VIP36 distribution was analyzed.
Main Results:
- Endogenous VIP36 localizes to the Golgi apparatus and early secretory pathway in MDCK and Vero cells.
- VIP36 shows partial overlap with Golgi markers and colocalizes with ER-Golgi intermediate structures.
- VIP36 undergoes N-linked carbohydrate modification, suggesting medial Golgi processing.
- VIP36 segregates from resident Golgi proteins and co-distributes with ER-Golgi recycling proteins after BFA treatment.
Conclusions:
- VIP36 is localized to the Golgi apparatus and early secretory pathway, with saturable retention.
- VIP36 participates in the cycling of anterograde cargo through ER-Golgi intermediate compartments.
- VIP36 is a dynamic component of the ER-Golgi recycling system.