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When a transmembrane channel isn't, or how biophysics and biochemistry (mis)communicate
1Department of Bioengineering, University of Washington, Seattle, WA 98105, USA.
Biochimica Et Biophysica Acta. Biomembranes
|February 7, 2018
Summary
Annexins bind acidic phospholipids, but whether they form ion channels or remain peripheral membrane proteins is debated. This review examines 30 years of annexin-lipid interaction data, focusing on lipid rearrangements.
Area of Science:
- Biochemistry
- Molecular Biology
- Membrane Biophysics
Background:
- Annexins are calcium-dependent phospholipid-binding proteins.
- Annexin A5, the archetypal member, has an unknown function despite structural data.
- Speculation exists regarding annexins forming transmembrane ion channels.
Purpose of the Study:
- To review annexin-lipid interactions over the past 30 years.
- To examine the controversy between peripheral assembly and transmembrane insertion hypotheses.
- To highlight the role of lipid rearrangements in annexin binding.
Main Methods:
- Literature review of studies on annexin-lipid interactions.
- Analysis of data supporting peripheral vs. transmembrane models.
- Focus on biochemical and biophysical evidence.
Main Results:
- Annexin binding to membranes is well-characterized as peripheral assembly.
- The ion channel hypothesis lacks definitive evidence but persists.
- Annexin binding can induce significant lipid rearrangements.
Conclusions:
- The precise functional role of annexins at membranes remains debated.
- Lipid rearrangements induced by annexins may be key to their function.
- Further research is needed to resolve the peripheral vs. transmembrane controversy.