Imaging the selective binding of synapsin to anionic membrane domains.
Synapsins are membrane-associated proteins that cover the surface of synaptic vesicles and are responsible for maintaining a pool of neurotransmitter-loaded vesicles for use during neuronal activity. We have used atomic force microscopy (AFM) to study the interaction of synapsin I with negatively charged lipid domains in phase-separated supported lipid bilayers prepared from mixtures of phosphatidylcholines (PCs) and phosphatidylserines (PSs). The results indicate a mixture of electrostatic binding to anionic PS-rich domains as well as some nonspecific binding to the PC phase. Interestingly, both protein binding and scanning with synapsin-coated AFM tips can be used to visualize charged lipid domains that cannot be detected by topography alone.
Murray
Jill
J
Steacie Institute for Molecular Sciences, National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada.
Cuccia
Louis
L
Ianoul
Anatoli
A
Cheetham
James J
JJ
Johnston
Linda J
LJ
D000838:Anions / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D008051:Lipid Bilayers / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force / Q000379:methods; D020527:Microscopy, Scanning Probe; D010713:Phosphatidylcholines / Q000737:chemistry; D010718:Phosphatidylserines / Q000737:chemistry; D011485:Protein Binding; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D016704:Synapsins / Q000737:chemistry*; D013572:Synaptic Vesicles / Q000737:chemistry
D000838:Anions; D008051:Lipid Bilayers; D008563:Membrane Lipids; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D016704:Synapsins