membranelocated

Membranelocated is a term used to describe the localization of a molecule, complex, or biological process at, on, or within cellular membranes. It encompasses components embedded in the lipid bilayer, those attached to membrane surfaces, and molecules associated with membrane interfaces such as the cytosolic leaflet or organelle membranes. The concept applies to the plasma membrane as well as internal membranes of organelles like the endoplasmic reticulum, Golgi apparatus, mitochondria, and lysosomes, including membrane microdomains.

Proteins become membranelocated through several mechanisms: transmembrane domains that span the bilayer; peripheral associations via electrostatic interactions with phospholipids; and covalent lipid anchors such as myristoyl, palmitoyl, or prenyl groups, or GPI anchors. Lipids and lipid-bound proteins can also be considered membranelocated when they reside in or on the membrane itself. Localization can be influenced by cellular signals, post-translational modifications, and interactions with other membrane-associated proteins.

Membranelocation is often essential for function, enabling signal reception, transport, vesicular trafficking, and enzymatic activity. Localization can be dynamic, with proteins shuttling between cytosolic and membrane-associated states in response to stimuli. Mislocalization can contribute to disease, including certain cancers and neurodegenerative disorders, underscoring the importance of proper membrane association in cellular physiology.

Techniques to study membranelocation include subcellular fractionation and Western blotting, immunofluorescence and confocal microscopy, and live-cell imaging with fluorescent fusion proteins. Proximity labeling methods and mass spectrometry are also used to map membrane-associated proteomes and lipid interactions. See also: membrane protein, protein localization, lipid raft, membrane trafficking.