AI Article Synopsis
- The mitochondria-associated membrane (MAM) is a specialized area of the endoplasmic reticulum (ER) that helps in the transfer of ions, lipids, and metabolites between the ER and mitochondria.
- The study reveals that a process called palmitoylation, which involves the attachment of fatty acids to proteins, helps ER-localized proteins like TMX and calnexin to become more concentrated in the MAM.
- Disrupting palmitoylation through mutations or chemical interference prevents proper positioning of these proteins in the MAM, highlighting the importance of palmitoylation for the function of certain ER proteins.
Article Abstract
The mitochondria-associated membrane (MAM) is a domain of the endoplasmic reticulum (ER) that mediates the exchange of ions, lipids and metabolites between the ER and mitochondria. ER chaperones and oxidoreductases are critical components of the MAM. However, the localization motifs and mechanisms for most MAM proteins have remained elusive. Using two highly related ER oxidoreductases as a model system, we now show that palmitoylation enriches ER-localized proteins on the MAM. We demonstrate that palmitoylation of cysteine residue(s) adjacent to the membrane-spanning domain promotes MAM enrichment of the transmembrane thioredoxin family protein TMX. In addition to TMX, our results also show that calnexin shuttles between the rough ER and the MAM depending on its palmitoylation status. Mutation of the TMX and calnexin palmitoylation sites and chemical interference with palmitoylation disrupt their MAM enrichment. Since ER-localized heme oxygenase-1, but not cytosolic GRP75 require palmitoylation to reside on the MAM, our findings identify palmitoylation as key for MAM enrichment of ER membrane proteins.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3261551 | PMC |
| http://dx.doi.org/10.1038/emboj.2011.384 | DOI Listing |
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Article Synopsis
- The mitochondria-associated membrane (MAM) is a specialized area of the endoplasmic reticulum (ER) that helps in the transfer of ions, lipids, and metabolites between the ER and mitochondria.
- The study reveals that a process called palmitoylation, which involves the attachment of fatty acids to proteins, helps ER-localized proteins like TMX and calnexin to become more concentrated in the MAM.
- Disrupting palmitoylation through mutations or chemical interference prevents proper positioning of these proteins in the MAM, highlighting the importance of palmitoylation for the function of certain ER proteins.
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