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Title | The endoplasmic reticulum connects to the nucleus by constricted junctions that mature after mitosis. |
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Journal, issue, pages | EMBO Rep, Vol. 25, Issue 7, Page 3137-3159, Year 2024 |
Publish date | Jun 14, 2024 |
Authors | Helena Bragulat-Teixidor / Keisuke Ishihara / Gréta Martina Szücs / Shotaro Otsuka / |
PubMed Abstract | Junctions between the endoplasmic reticulum (ER) and the outer membrane of the nuclear envelope (NE) physically connect both organelles. These ER-NE junctions are essential for supplying the NE with ...Junctions between the endoplasmic reticulum (ER) and the outer membrane of the nuclear envelope (NE) physically connect both organelles. These ER-NE junctions are essential for supplying the NE with lipids and proteins synthesized in the ER. However, little is known about the structure of these ER-NE junctions. Here, we systematically study the ultrastructure of ER-NE junctions in cryo-fixed mammalian cells staged in anaphase, telophase, and interphase by correlating live cell imaging with three-dimensional electron microscopy. Our results show that ER-NE junctions in interphase cells have a pronounced hourglass shape with a constricted neck of 7-20 nm width. This morphology is significantly distinct from that of junctions within the ER network, and their morphology emerges as early as telophase. The highly constricted ER-NE junctions are seen in several mammalian cell types, but not in budding yeast. We speculate that the unique and highly constricted ER-NE junctions are regulated via novel mechanisms that contribute to ER-to-NE lipid and protein traffic in higher eukaryotes. |
External links | EMBO Rep / PubMed:38877171 / PubMed Central |
Methods | EM (tomography) |
Structure data | EMDB-50068: Electron tomogram of ER-nuclear envelope junction of HeLa cell in interphase EMDB-50110: Electron tomogram of ER-nuclear envelope junction of HeLa cell in early telophase EMDB-50115: Electron tomogram of ER-ER junction of HeLa cell in interphase EMDB-50134: Electron tomogram of ER-ER/nuclear envelope junction of HeLa cell in late anaphase |
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