Protein-protein interactions in AQP regulation - biophysical characterization of AQP0-CaM and AQP2-LIP5 complex formation
| Autor: | Sara Linse, Susanna Törnroth-Horsefield, Jennifer Virginia Roche, Caroline Olsson, Stefan Kreida |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Models Molecular Water transport Aquaporin 2 Calmodulin biology Endosomal Sorting Complexes Required for Transport Chemistry Microscale thermophoresis Cooperativity Context (language use) Gating Plasma protein binding Aquaporins Protein–protein interaction 03 medical and health sciences 030104 developmental biology biology.protein Biophysics Humans Physical and Theoretical Chemistry Eye Proteins Protein Binding |
| Zdroj: | Faraday discussions. 209 |
| ISSN: | 1364-5498 |
| Popis: | Protein-protein interactions play important roles in regulating human aquaporins (AQP) by gating as well as trafficking. While structural and functional studies have provided detailed knowledge of AQP transport mechanisms, selectivity as well as gating by conformational changes of loops or termini, the mechanism behind how protein-protein interactions control AQP-mediated water transport through cellular membranes remains poorly characterized. Here we explore the interaction between two human AQPs and regulatory proteins: the interaction between AQP0 and calmodulin, which mediates AQP0 gating, as well as the interaction between AQP2 and LIP5, which is involved in trafficking. Using microscale thermophoresis (MST) and fluorescence anisotropy, two methods that have the advantage of low sample consumption and detergent compatibility, we show that the interactions can be studied using both full-length AQPs and AQP peptides corresponding to the regulatory protein binding sites. However, full-length AQPs gave better reproducibility between methods and for the first time revealed that AQP0 binds CaM in a cooperative manner, which was not seen in experiments using peptides. Our study highlights that, while peptides are great tools for locating binding sites and pinpointing interacting residues, full-length proteins may give additional insights, such as binding mechanism, allostery and cooperativity, important parameters for understanding protein-protein mediated regulation in the cellular context. Our work provides a platform for further studies of AQP regulation that may be of interest for designing drugs that target AQP complexes as well as the development of artificial bio-mimetic water channels for water-purification purposes. |
| Databáze: | OpenAIRE |
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