The endoplasmic reticulum's (ER's) structure is directly linked to the many functions of the ER, but its formation is not fully understood. We investigate how the ER-membrane curving protein reticulon 4 (Rtn4) localizes to and organizes in the membrane and how that affects the local ER structure. We show a strong correlation between the local Rtn4 density and the local ER membrane curvature. Our data further reveal that the typical ER tubule possesses an elliptical cross-section with Rtn4 enriched at either end of the major axis. Rtn4 oligomers are linear shaped, contain about five copies of the protein, and preferentially orient parallel to the tubule axis. Our observations support a mechanism in which oligomerization leads to an increase of the local Rtn4 concentration with each molecule, increasing membrane curvature through a hairpin wedging mechanism. This quantitative analysis of Rtn4 and its effects on the ER membrane result in a new model of tubule shape as it relates to Rtn4.
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http://dx.doi.org/10.1083/jcb.202301112 | DOI Listing |
Cell Rep
July 2024
UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Cambridge CB2 0AH, UK. Electronic address:
Cell functions rely on intracellular transport systems distributing bioactive molecules with high spatiotemporal accuracy. The endoplasmic reticulum (ER) tubular network constitutes a system for delivering luminal solutes, including Ca, across the cell periphery. How the ER structure enables this nanofluidic transport system is unclear.
View Article and Find Full Text PDFNature
July 2024
Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY, USA.
Directed cell migration is driven by the front-back polarization of intracellular signalling. Receptor tyrosine kinases and other inputs activate local signals that trigger membrane protrusions at the front. Equally important is a long-range inhibitory mechanism that suppresses signalling at the back to prevent the formation of multiple fronts.
View Article and Find Full Text PDFTissue Eng Regen Med
July 2024
Department of Gastroenterology, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, No.28, Fuxing Road, Haidian District, Beijing City, 100853, China.
Background: Hepatic fibrosis (HF) is a histopathological change in the process of long-term liver injury caused by cytokine secretion and internal environment disturbance, resulting in excessive liver repair and fiber scar. Nogo-B protein is widely distributed in peripheral tissues and organs and can regulate the migration of endothelial cells by activating TGF-β1 in vascular remodeling after injury. Nogo-B has been shown to promote organ fibrosis.
View Article and Find Full Text PDFJ Cell Biol
October 2023
Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
The endoplasmic reticulum's (ER's) structure is directly linked to the many functions of the ER, but its formation is not fully understood. We investigate how the ER-membrane curving protein reticulon 4 (Rtn4) localizes to and organizes in the membrane and how that affects the local ER structure. We show a strong correlation between the local Rtn4 density and the local ER membrane curvature.
View Article and Find Full Text PDFbioRxiv
January 2023
Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
Unlabelled: The endoplasmic reticulum’s (ER) structure is directly linked to the many functions of the ER but its formation is not fully understood. We investigate how the ER-membrane curving protein reticulon 4 (Rtn4) localizes to and organizes in the membrane and how that affects local ER structure. We show a strong correlation between the local Rtn4 density and the local ER membrane curvature.
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