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Structural insights into aquaporin selectivity and regulation
Stefan Kreida1, Susanna Törnroth-Horsefield1
1Department of Biochemistry and Structural Biology, Centre for Protein Molecular Science, Lund University, Lund, Sweden.
Current Opinion in Structural Biology
|September 7, 2015
Summary
Aquaporins, essential membrane proteins, are well-characterized structurally. New insights into their water transport mechanisms and regulation are emerging from detailed structural studies, including visualization of channel hydrogens.
Area of Science:
- Structural biology
- Membrane protein research
- Biophysics
Background:
- Aquaporins are a diverse family of membrane transport proteins crucial for water homeostasis.
- Fourteen distinct aquaporin structures from various organisms are currently known.
- Despite a conserved fold and water permeation mechanism, aquaporins exhibit variations in selectivity and regulation.
Purpose of the Study:
- To highlight recent advancements in aquaporin structural biology.
- To explore recurring structural themes in eukaryotic aquaporin gating and trafficking.
- To present new insights into the proton exclusion mechanism of aquaporins.
Main Methods:
- Analysis of existing structural data for aquaporin families.
- Investigation of recent high-resolution structural studies on eukaryotic aquaporins.
- Examination of a sub-angstrom resolution structure of a yeast aquaporin.
Main Results:
- Identification of common structural solutions for aquaporin gating and trafficking in eukaryotes.
- Visualization of hydrogen atoms within the water-conducting channel of a yeast aquaporin.
- Detailed understanding of the proton exclusion mechanism at near-atomic resolution.
Conclusions:
- Aquaporin regulation likely involves a limited set of structural strategies.
- High-resolution structural data provides unprecedented insights into aquaporin function.
- Structural biology continues to refine our understanding of water transport and selectivity in aquaporins.
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