Interaction between FIP5 and SNX18 regulates epithelial lumen formation
Carly Willenborg1, Jian Jing, Christine Wu
1Department of Cell and Developmental Biology, University of Colorado Denver, Aurora, CO 80045, USA.
The Journal of Cell Biology
|October 5, 2011
Summary
The FIP5-SNX18 complex is crucial for epithelial lumen formation by transporting apical proteins. This discovery sheds light on the machinery driving polarized endocytic transport during early lumen development.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Epithelial lumen morphogenesis involves apical protein transport via endocytic compartments.
- The machinery mediating this polarized transport is not fully understood.
- Rab11 GTPase and FIP5 are known regulators of polarized endocytic transport.
Purpose of the Study:
- To identify novel proteins involved in epithelial lumen morphogenesis.
- To characterize the role of FIP5 and sorting nexin 18 (SNX18) in this process.
- To elucidate the mechanism of apical protein transport during lumen initiation.
Main Methods:
- Protein interaction studies to identify FIP5-binding partners.
- Cellular localization and functional assays in epithelial cells.
- Lipid-binding and membrane tubulation experiments.
Main Results:
- Sorting nexin 18 (SNX18) was identified as a novel FIP5-interacting protein.
- FIP5 mediates apical protein transport from endosomes to the plasma membrane.
- FIP5 and SNX18 are essential for early epithelial apical lumen formation.
- Both FIP5 and SNX18 bind lipids, with FIP5 enhancing SNX18's membrane tubulation.
Conclusions:
- The FIP5-SNX18 complex plays a critical role in the polarized transport of apical proteins.
- This complex is vital for the initiation of apical lumen formation in epithelial cells.
- Findings suggest a role for the FIP5-SNX18 complex in endocytic carrier formation and/or scission.
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