Structures of the FXYD regulatory proteins in lipid micelles and membranes
The FXYD membrane proteins constitute a family of conserved auxiliary subunits of the Na,K-ATPase, and have been the focus of recent attention due to their ability to finely regulate the activity of the enzyme complex in various physiological settings. In this review we describe the structures of the proteins, as well as their dynamics and their associations with the lipid bilayer membrane, which we have recently determined by NMR spectroscopy. Although the proteins are relatively small, their genes contain as many as six to nine small exons, and the coincidence of structured protein segments with their genetic elements suggests assembly from discrete structural modules through exon shuffling. The three-dimensional structures and backbone dynamics provide the foundation for understanding their intra-membrane association with the Na,K-ATPase α subunit, and the structure of FXYD1 suggests a mechanism whereby the phosphorylation of conserved Ser residues, by protein kinases A and C, could induce a conformational change in the cytoplasmic domain of the protein, to modulate its interaction with the α subunit.
KeywordsFXYD Na,K-ATPase Structure Membrane protein Micelles Membrane NMR
Unable to display preview. Download preview PDF.
- Cornelius F, Mahmmoud YA (2003) News Physiol Sci 18:119–124Google Scholar
- Crambert G, Geering K (2003) Sci STKE 2003, RE1Google Scholar
- Franzin CM, Marassi FM (2005) NMR Structure determination of proteins in bilayer lipid membranes: the FXYD family proteins. In: Tien HT, Ottova-Leitmannova A (eds) Advances in planar lipid bilayers and liposomes. Elsevier, Amsterdam, pp 77–93Google Scholar
- Vinton BB, Wertz SL, Jacob J, Steere J, Grisham CM, Cafiso DS, Sando JJ (1998) Biochem J 330(Pt 3):1433–1442Google Scholar