The synthesis of endoplasmic reticulum (ER)-derived transport vesicles is dictated by the contents and derivation of the cellular cytosol. The ER transport vesicles synthesized in the presence of gastric epithelial ce...The synthesis of endoplasmic reticulum (ER)-derived transport vesicles is dictated by the contents and derivation of the cellular cytosol. The ER transport vesicles synthesized in the presence of gastric epithelial cells cytosol are destined for en bloc fusion with apical epithelial membrane, whereas those generated in hepa-tocytes-derived cytosol are destined for en bloc fusion with basolateral membrane. Moreover, during assembly of the dominant fraction of the apical or basolateral transport vesicles, a sub-stantial fraction of the vesicles is produced that fuses with endosomes, and the vesicles with still unknown destination that remain in cytosol. The process of ER vesicles synthesis is blocked by RNase treatment, whereas Golgi vesicles as-sembly is not affected. The experiments indicate that transport vesicles’ membrane composition and fidelity of its construction is defined in ER. The process involves synchronous membrane lipid synthesis, cotranslational intercalation of integral membrane proteins and containment of the vesicular cargo.展开更多
文摘The synthesis of endoplasmic reticulum (ER)-derived transport vesicles is dictated by the contents and derivation of the cellular cytosol. The ER transport vesicles synthesized in the presence of gastric epithelial cells cytosol are destined for en bloc fusion with apical epithelial membrane, whereas those generated in hepa-tocytes-derived cytosol are destined for en bloc fusion with basolateral membrane. Moreover, during assembly of the dominant fraction of the apical or basolateral transport vesicles, a sub-stantial fraction of the vesicles is produced that fuses with endosomes, and the vesicles with still unknown destination that remain in cytosol. The process of ER vesicles synthesis is blocked by RNase treatment, whereas Golgi vesicles as-sembly is not affected. The experiments indicate that transport vesicles’ membrane composition and fidelity of its construction is defined in ER. The process involves synchronous membrane lipid synthesis, cotranslational intercalation of integral membrane proteins and containment of the vesicular cargo.
