Cortical actin contributes to spatial organization of ER-PM junctions

Endoplasmic reticulum-plasma membrane (ER-PM) junctions mediate crucial activities ranging from Ca signaling to lipid metabolism. Spatial organization of ER-PM junctions may modulate the extent and location of these cellular activities. However, the morphology and distribution of ER-PM junctions are...

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Bibliographic Details
Published in:Molecular biology of the cell 2017-11, Vol.28 (23), p.3171-3180
Main Authors: Hsieh, Ting-Sung, Chen, Yu-Ju, Chang, Chi-Lun, Lee, Wan-Ru, Liou, Jen
Format: Article
Language:English
Subjects:
Actin Cytoskeleton - metabolism
Actins - metabolism
Brief Reports
Calcium - metabolism
Cell Membrane - metabolism
Endoplasmic Reticulum - metabolism
Endoplasmic Reticulum - physiology
HeLa Cells
Homeostasis
Humans
Membrane Proteins - metabolism
Phosphatidylinositols - metabolism
Signal Transduction
Spatial Analysis
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Summary:Endoplasmic reticulum-plasma membrane (ER-PM) junctions mediate crucial activities ranging from Ca signaling to lipid metabolism. Spatial organization of ER-PM junctions may modulate the extent and location of these cellular activities. However, the morphology and distribution of ER-PM junctions are not well characterized. Using photoactivated localization microscopy, we reveal that the contact area of single ER-PM junctions is mainly oblong with the dimensions of ∼120 nm × ∼80 nm in HeLa cells. Using total internal reflection fluorescence microscopy and structure illumination microscopy, we show that cortical actin contributes to spatial distribution and stability of ER-PM junctions. Further functional assays suggest that intact F-actin architecture is required for phosphatidylinositol 4,5-bisphosphate homeostasis mediated by Nir2 at ER-PM junctions. Together, our study provides quantitative information on spatial organization of ER-PM junctions that is in part regulated by F-actin. We envision that functions of ER-PM junctions can be differentially regulated through dynamic actin remodeling during cellular processes.
ISSN:1059-1524
1939-4586
DOI:10.1091/mbc.E17-06-0377