How curved membranes recruit amphipathic helices and protein anchoring motifs.
Lipids and several specialized proteins are thought to be able to sense the curvature of membranes (MC). Here we used quantitative fluorescence microscopy to measure curvature-selective binding of amphipathic motifs on single liposomes 50-700 nm in diameter. Our results revealed that sensing is predominantly mediated by a higher density of binding sites on curved membranes instead of higher affinity. We proposed a model based on curvature-induced defects in lipid packing that related these findings to lipid sorting and accurately predicted the existence of a new ubiquitous class of curvature sensors: membrane-anchored proteins. The fact that unrelated structural motifs such as alpha-helices and alkyl chains sense MC led us to propose that MC sensing is a generic property of curved membranes rather than a property of the anchoring molecules. We therefore anticipate that MC will promote the redistribution of proteins that are anchored in membranes through other types of hydrophobic moieties.
Hatzakis
Nikos S
NS
Bio-Nanotechnology Laboratory, Department of Neuroscience and Pharmacology & Nano-Science Center, University of Copenhagen, Copenhagen, Denmark.
Bhatia
Vikram K
VK
Larsen
Jannik
J
Madsen
Kenneth L
KL
Bolinger
Pierre-Yves
PY
Kunding
Andreas H
AH
Castillo
John
J
Gether
Ulrik
U
Hedegård
Per
P
Stamou
Dimitrios
D
D019921:Biotinylation; D005452:Fluoresceins / Q000737:chemistry; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008563:Membrane Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D008566:Membranes / Q000378:metabolism / Q000648:ultrastructure*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry
D005452:Fluoresceins; D008051:Lipid Bilayers; D008081:Liposomes; D008563:Membrane Lipids; D008565:Membrane Proteins; D010455:Peptides