Membrane shape modulates transmembrane protein distribution.
Although membrane shape varies greatly throughout the cell, the contribution of membrane curvature to transmembrane protein targeting is unknown because of the numerous sorting mechanisms that take place concurrently in cells. To isolate the effect of membrane shape, we used cell-sized giant unilamellar vesicles (GUVs) containing either the potassium channel KvAP or the water channel AQP0 to form membrane nanotubes with controlled radii. Whereas the AQP0 concentrations in flat and curved membranes were indistinguishable, KvAP was enriched in the tubes, with greater enrichment in more highly curved membranes. Fluorescence recovery after photobleaching measurements showed that both proteins could freely diffuse through the neck between the tube and GUV, and the effect of each protein on membrane shape and stiffness was characterized using a thermodynamic sorting model. This study establishes the importance of membrane shape for targeting transmembrane proteins and provides a method for determining the effective shape and flexibility of membrane proteins.
Centre de Recherche, Institut Curie, Paris F-75248, France; CNRS, PhysicoChimie Curie, UMR168, Paris F-75248, France; Université Pierre et Marie Curie, Paris F-75252, France; Kavli Institute for Brain and Mind, UCSD, La Jolla, CA 92093, USA.
Sophie
S
Aimon
Laboratoire Matière et Systèmes Complexes, CNRS/Université Paris-Diderot, UMR 7057, 75205 Paris Cedex 13, France.
Andrew
A
Callan-Jones
Centre de Recherche, Institut Curie, Paris F-75248, France; CNRS, PhysicoChimie Curie, UMR168, Paris F-75248, France; Université Pierre et Marie Curie, Paris F-75252, France; CelTisPhyBio Labex, Paris Sciences et Lettres, 75005 Paris, France.
Alice
A
Berthaud
Centre de Recherche, Institut Curie, Paris F-75248, France; CelTisPhyBio Labex, Paris Sciences et Lettres, 75005 Paris, France; CNRS, Subcellular Structure and Cellular Dynamics, UMR144, Paris F-75248, France.
Mathieu
M
Pinot
Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-3017, USA. Electronic address: gilman.toombes@nih.gov.
Gilman E S
GE
Toombes
Centre de Recherche, Institut Curie, Paris F-75248, France; CNRS, PhysicoChimie Curie, UMR168, Paris F-75248, France; Université Pierre et Marie Curie, Paris F-75252, France; CelTisPhyBio Labex, Paris Sciences et Lettres, 75005 Paris, France.
Patricia
P
Bassereau
D000818:Animals; D020346:Aquaporins / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism*; D053835:Unilamellar Liposomes / Q000737:chemistry / Q000378:metabolism
D020346:Aquaporins; D024642:Potassium Channels, Voltage-Gated; D053835:Unilamellar Liposomes