A hollow TFG condensate spatially compartmentalizes the early secretory pathway

Abstract In the early secretory pathway, endoplasmic reticulum (ER) and Golgi membranes form a nearly spherical interface. In this ribosome-excluding zone, bidirectional transport of cargo coincides with a spatial segregation of anterograde and retrograde carriers by an unknown mechanism. We show th...

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Main Authors: Savannah M. Bogus, William R. Wegeng, Miguel Ruiz, Sindy R. Chavez, Samantha N. Cheung, Khalid S. M. Noori, Ingrid R. Niesman, Andreas M. Ernst
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-59118-1
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author Savannah M. Bogus
William R. Wegeng
Miguel Ruiz
Sindy R. Chavez
Samantha N. Cheung
Khalid S. M. Noori
Ingrid R. Niesman
Andreas M. Ernst
author_facet Savannah M. Bogus
William R. Wegeng
Miguel Ruiz
Sindy R. Chavez
Samantha N. Cheung
Khalid S. M. Noori
Ingrid R. Niesman
Andreas M. Ernst
author_sort Savannah M. Bogus
collection DOAJ
description Abstract In the early secretory pathway, endoplasmic reticulum (ER) and Golgi membranes form a nearly spherical interface. In this ribosome-excluding zone, bidirectional transport of cargo coincides with a spatial segregation of anterograde and retrograde carriers by an unknown mechanism. We show that at physiological conditions, the Trk-fused gene (TFG) self-organizes to form a hollow, anisotropic condensate that matches the dimensions of the ER–Golgi interface and is dynamically regulated across the cell cycle. Regularly spaced hydrophobic residues in TFG control the condensation mechanism and result in a porous condensate surface. We find that TFG condensates act as a molecular sieve capable of allowing access of anterograde coats (COPII) to the condensate interior while restricting retrograde coats (COPI). We propose that a hollow TFG condensate structures the ER–Golgi interface to create a diffusion-limited space for anterograde transport. We further propose that TFG condensates optimize membrane flux by insulating secretory carriers in their lumen from retrograde carriers outside TFG cages.
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issn 2041-1723
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spelling doaj-art-6f104f51b38f44628592fa11709c9d222025-08-20T03:18:28ZengNature PortfolioNature Communications2041-17232025-04-0116111510.1038/s41467-025-59118-1A hollow TFG condensate spatially compartmentalizes the early secretory pathwaySavannah M. Bogus0William R. Wegeng1Miguel Ruiz2Sindy R. Chavez3Samantha N. Cheung4Khalid S. M. Noori5Ingrid R. Niesman6Andreas M. Ernst7Department of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoDepartment of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoDepartment of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoDepartment of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoDepartment of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoDepartment of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoDepartment of Biology, San Diego State UniversityDepartment of Cell and Developmental Biology, School of Biological Sciences, University of California San DiegoAbstract In the early secretory pathway, endoplasmic reticulum (ER) and Golgi membranes form a nearly spherical interface. In this ribosome-excluding zone, bidirectional transport of cargo coincides with a spatial segregation of anterograde and retrograde carriers by an unknown mechanism. We show that at physiological conditions, the Trk-fused gene (TFG) self-organizes to form a hollow, anisotropic condensate that matches the dimensions of the ER–Golgi interface and is dynamically regulated across the cell cycle. Regularly spaced hydrophobic residues in TFG control the condensation mechanism and result in a porous condensate surface. We find that TFG condensates act as a molecular sieve capable of allowing access of anterograde coats (COPII) to the condensate interior while restricting retrograde coats (COPI). We propose that a hollow TFG condensate structures the ER–Golgi interface to create a diffusion-limited space for anterograde transport. We further propose that TFG condensates optimize membrane flux by insulating secretory carriers in their lumen from retrograde carriers outside TFG cages.https://doi.org/10.1038/s41467-025-59118-1
spellingShingle Savannah M. Bogus
William R. Wegeng
Miguel Ruiz
Sindy R. Chavez
Samantha N. Cheung
Khalid S. M. Noori
Ingrid R. Niesman
Andreas M. Ernst
A hollow TFG condensate spatially compartmentalizes the early secretory pathway
Nature Communications
title A hollow TFG condensate spatially compartmentalizes the early secretory pathway
title_full A hollow TFG condensate spatially compartmentalizes the early secretory pathway
title_fullStr A hollow TFG condensate spatially compartmentalizes the early secretory pathway
title_full_unstemmed A hollow TFG condensate spatially compartmentalizes the early secretory pathway
title_short A hollow TFG condensate spatially compartmentalizes the early secretory pathway
title_sort hollow tfg condensate spatially compartmentalizes the early secretory pathway
url https://doi.org/10.1038/s41467-025-59118-1
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