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Structural Insights into AQP2 Targeting to Multivesicular Bodies
Jennifer Virginia Roche1, Veronika Nesverova2, Caroline Olsson3
1Department of Biochemistry and Structural Biology, Lund University, PO Box 124, 221 00, Lund, Sweden. jennifer.roche@biochemistry.lu.se.
International Journal of Molecular Sciences
|October 31, 2019
Summary
Lysosomal trafficking regulator-interacting protein 5 (LIP5) helps remove aquaporin 2 (AQP2) from kidney cells. This study reveals LIP5’s structural interaction with AQP2, clarifying water balance regulation.
Area of Science:
- Cell biology
- Molecular biology
- Physiology
Background:
- Vasopressin regulates water homeostasis by controlling aquaporin 2 (AQP2) trafficking in renal collecting ducts.
- AQP2 removal involves endocytosis, sorting into multivesicular bodies (MVBs), and potential recycling, degradation, or exosomal release.
- Lysosomal trafficking regulator-interacting protein 5 (LIP5) coordinates ESCRT-III and Vps4 ATPase for MVB protein insertion.
Purpose of the Study:
- To elucidate the structural mechanism of LIP5 interaction with the membrane protein AQP2.
- To provide the first structural insights into how LIP5 facilitates membrane protein insertion into MVB inner vesicles.
Main Methods:
- Fluorescence spectroscopy
- Computer modeling
- Structural analysis of protein interactions
Main Results:
- A structural model of LIP5 interaction with human AQP2 was generated.
- The AQP2 tetramer binds up to two LIP5 molecules.
- The LIP5-AQP2 interaction resembles the LIP5-CHMP1B interaction within the ESCRT-III complex.
Conclusions:
- This study provides the first structural evidence for LIP5 binding to AQP2.
- Understanding LIP5-AQP2 interaction enhances knowledge of AQP2 trafficking and MVB formation.
- These findings contribute to understanding water homeostasis regulation at a molecular level.
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