membraanresident

Membraanresident is a term used in cell biology to describe proteins or other molecules that reside in cellular membranes and are retained there over time. In practice, membrane resident proteins are typically integral or strongly membrane-associated proteins that function within the lipid bilayer or on its surfaces, rather than being secreted into the extracellular space or released into the cytosol. They are found in the plasma membrane as well as in internal membranes of the endomembrane system, including the endoplasmic reticulum, Golgi apparatus, lysosomes, endosomes, and in mitochondrial and chloroplast membranes.

Retention in the membrane is driven by structural features and sorting signals. Many resident proteins contain transmembrane domains that anchor them in the bilayer, while others are tethered to the membrane by lipid modifications or peripheral associations. Certain organelle-specific residents carry retrieval or retention motifs, such as KDEL or KKXX for endoplasmic reticulum residents, which help to prevent their loss during vesicular trafficking. In addition, targeting sequences direct proteins to particular membranes, where they remain under normal conditions.

Membrane resident proteins can be integral, spanning the membrane one or multiple times, or lipid-anchored peripheral proteins. They include monotopic and multi-pass receptors, channels, transporters, enzymes, and scaffolds that contribute to signaling, transport, metabolism, and structural organization of the membrane. Their residency is essential for maintaining compartmentalization and specialized functions across cellular membranes.

In research, distinguishing resident proteins from secreted or transiently associated ones informs studies of trafficking, membrane biology, and proteome organization. Residency can be dynamic, changing in response to cellular states or signaling events.