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Protein-protein interactions in AQP regulation - biophysical characterization of AQP0-CaM and AQP2-LIP5 complex formation

Kreida*, Stefan LU ; Roche*, Jennifer LU ; Olsson, Caroline; Linse, Sara LU and Horsefield, Susanna LU (2018) In Faraday Discussions 209(35). p.35-54
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Faraday Discussions
volume
209
issue
35
pages
19 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85054126011
ISSN
1359-6640
DOI
10.1039/c8fd00065d
language
English
LU publication?
yes
id
36efa0f4-46c1-4349-8329-c08b06356a1a
date added to LUP
2018-10-15 09:12:28
date last changed
2019-10-15 06:48:01
@article{36efa0f4-46c1-4349-8329-c08b06356a1a,
  abstract     = {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.},
  author       = {Kreida*, Stefan and Roche*, Jennifer and Olsson, Caroline and Linse, Sara and Horsefield, Susanna},
  issn         = {1359-6640},
  language     = {eng},
  number       = {35},
  pages        = {35--54},
  publisher    = {Royal Society of Chemistry},
  series       = {Faraday Discussions},
  title        = {Protein-protein interactions in AQP regulation - biophysical characterization of AQP0-CaM and AQP2-LIP5 complex formation},
  url          = {http://dx.doi.org/10.1039/c8fd00065d},
  volume       = {209},
  year         = {2018},
}