Membrane fusion induced by the major lipid-binding domain of the cytoskeletal protein talin.
Secondary structure predictions have led to the identification of a major membrane-anchoring domain of the cytoskeletal protein talin spanning from amino acid 385 to 406. Using a synthetically derived peptide of this region, researchers have shown that it inserts into POPC/POPG phospholipid membranes with a partition coefficient of K(app)=1.1+/-0.2 x 10(5) M(-1) and has an average molar reaction enthalpy of DeltaH=-2.5 kcal/mol, as determined by monolayer expansion technique and isothermic titration calorimetry [J. Biol. Chem. 275, 17954]. We applied resonance energy transfer (RET) assays to analyze the fusogenic properties of this peptide by lipid mixing and used liposomes containing carboxyfluorescein to measure the contents leakage. We directly visualized talin peptide-induced vesicle membrane fusion using cryo-electron microscopy. This is the first example of a cytoskeletal protein domain that can trigger membrane fusion that might be of importance for understanding membrane targeting and motile events at the leading edge of the cell.
Isenberg
Gerhard
G
Department of Biophysics E22, Technical University Munich, James-Franck-Str., D-85748 Garching, Germany.
Doerhoefer
Sabine
S
Hoekstra
Dick
D
Goldmann
Wolfgang H
WH
D020285:Cryoelectron Microscopy; D003599:Cytoskeleton / Q000378:metabolism*; D004735:Energy Transfer; D005452:Fluoresceins / Q000494:pharmacology; D007700:Kinetics; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000378:metabolism; D008561:Membrane Fusion; D008956:Models, Chemical; D008958:Models, Molecular; D010452:Peptide Biosynthesis; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016608:Talin / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics; D013997:Time Factors
D005452:Fluoresceins; D008055:Lipids; D008081:Liposomes; D016608:Talin; C024098:6-carboxyfluorescein