Membranbindingen

Membranbindingen are non-covalent interactions that attach proteins and other biomolecules to cellular membranes. They determine where enzymes, receptors and cytoskeletal proteins act at membranes and are often dynamic, allowing rapid changes in signaling and trafficking.

Binding modes include peripheral binding, where proteins associate with the membrane surface without spanning the bilayer, and integral binding, where proteins embed in or cross the membrane. A third mode involves lipid-anchored proteins, which are covalently linked to lipid groups that insert into the bilayer.

Mechanisms comprise electrostatic attraction between basic amino acids and negatively charged lipids (such as phosphatidylserine and phosphoinositides), insertion of amphipathic helices into the outer leaflet, and recognition by lipid-binding domains such as PH, C2, PX, FYVE and BAR domains. Lipid modifications (myristoylation, palmitoylation, prenylation) can also tether proteins to membranes.

Lipid composition and membrane curvature influence binding. Specific lipids like PI(4,5)P2 or PI3P provide binding sites, while cholesterol content and lipid packing affect affinity and geometry.

Regulation is common. Calcium ions, phosphorylation, and changes in lipid composition can modulate binding affinity, localization and function, with consequences for signaling, vesicle trafficking and cytoskeleton organization.

Study methods include liposome binding assays, co-sedimentation, surface plasmon resonance and fluorescence-based approaches; structural and computational analyses help identify binding motifs and domain functions.

Understanding membranbindingen is essential for cell biology; misregulation can contribute to diseases such as neurodegeneration and cancer, underscoring the importance of controlled membrane association.