The Endoplasmic Reticulum Membrane Is Permeable to Small Molecules
AUTOR(ES)
Le Gall, Sylvie
FONTE
The American Society for Cell Biology
RESUMO
The lumen of the endoplasmic reticulum (ER) differs from the cytosol in its content of ions and other small molecules, but it is unclear whether the ER membrane is as impermeable as other membranes in the cell. Here, we have tested the permeability of the ER membrane to small, nonphysiological molecules. We report that isolated ER vesicles allow different chemical modification reagents to pass from the outside into the lumen with little hindrance. In permeabilized cells, the ER membrane allows the passage of a small, charged modification reagent that is unable to cross the plasma membrane or the lysosomal and trans-Golgi membranes. A larger polar reagent of ∼5 kDa is unable to pass through the ER membrane. Permeation of the small molecules is passive because it occurs at low temperature in the absence of energy. These data indicate that the ER membrane is significantly more leaky than other cellular membranes, a property that may be required for protein folding and other functions of the ER.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=329208Documentos Relacionados
- Animal cells reversibly permeable to small molecules
- Golgi inheritance in small buds of Saccharomyces cerevisiae is linked to endoplasmic reticulum inheritance
- The unfolded protein response coordinates the production of endoplasmic reticulum protein and endoplasmic reticulum membrane.
- An ATP-binding membrane protein is required for protein translocation across the endoplasmic reticulum membrane.
- Probing for Membrane Domains in the Endoplasmic Reticulum: Retention and Degradation of Unassembled MHC Class I Molecules