MembranTrafficking

MembranTrafficking, often referred to as membrane trafficking, is the cellular process by which membrane-bound cargo and lipids are transported between organelles and the plasma membrane. It coordinates vesicle budding, cargo selection, transport, tethering, docking, and fusion, enabling proper distribution of proteins, receptors, and lipids across the endomembrane system, including the endoplasmic reticulum, Golgi apparatus, endosomes, lysosomes, and the plasma membrane.

Key components include coat protein complexes such as clathrin, COPI, and COPII, Rab GTPases that mark organelle identity, SNAREs that drive membrane fusion, tethering factors, and cytoskeletal motors. Transport occurs via secretory, endocytic, and recycling routes: the secretory pathway moves cargo from the ER through the Golgi to the plasma membrane or extracellular space; endocytosis internalizes material and receptors; endosomes sort cargo for recycling or degradation.

Regulation integrates signaling inputs with energy-dependent steps, using GTPase cycles, post-translational modifications, and adaptor proteins to adjust trafficking in response to nutrients, growth factors, and stress. Proper membrane trafficking maintains receptor availability, nutrient uptake, organelle biogenesis, and membrane composition essential for cell homeostasis.

Disruptions in membrane trafficking contribute to diseases such as neurodegenerative and metabolic disorders, immunodeficiencies, and cystic fibrosis. Research uses genetics, advanced imaging, biochemical assays, and model organisms to elucidate trafficking pathways and their roles in health and disease.