Golvmembran

Golvmembran, also referred to as the Golgi membrane, is the lipid bilayer that encloses the Golgi apparatus in eukaryotic cells. It forms a series of flattened, stacked cisternae near the endoplasmic reticulum and defines the boundary between the luminal space of the Golgi and the cytosol. The golvmembran contains the enzymes and transport machinery required for post-translational modification and sorting of proteins and lipids as they pass through the Golgi.

The membrane's composition includes typical eukaryotic phospholipids, cholesterol, and sphingolipids, with a complement of integral and peripheral proteins such as SNAREs, tethering factors, glycosyltransferases, sulfotransferases, and proton pumps. The Golgi exhibits cis-to-trans polarity, with different cisternae enriched for stage-specific enzymes, enabling sequential processing of cargo: glycosylation, sulfation, and maturation.

Vesicular trafficking through the golvmembran is mediated by coat protein complexes. COPII mediates anterograde transport from the ER to the Golgi, COPI mediates intra-Golgi and retrograde transport, and clathrin-dependent routes handle trafficking from the trans-Golgi network to endosomes, lysosomes, or the plasma membrane. SNAREs and tethering factors on the golvmembran help ensure correct vesicle fusion and cargo delivery.

Biogenesis and maintenance rely on cytoskeletal dynamics and lipid metabolism. The lumen of the Golgi is acidic, maintained by H+-ATPases, which helps regulate enzyme activity and cargo sorting. The golvmembran plays a central role in sorting secretory pathway cargo for secretion or delivery to lysosomes and the plasma membrane, and in the maturation of lysosomal enzymes via the mannose-6-phosphate pathway.

Disruption of Golgi membrane function can contribute to congenital disorders of glycosylation and other diseases, reflecting its essential role in cellular logistics.