Surface Morphometrics Reveals Local Membrane Thickness Variation in Organellar Subcompartments

Authors

• Michaela Medina
• Ya-Ting Chang
• Hamidreza Rahmani
• Mark Frank
• Zidan Khan
• Daniel Fuentes
• Frederick A Heberle
• M Neal Waxham
• Benjamin A Barad
• Danielle A Grotjahn

Language

English

Publication Date

3-2-2026

Journal

Journal of Cell Biology

DOI

10.1083/jcb.202505059

PMID

41474626

PMCID

PMC12755900

PubMedCentral® Posted Date

12-26-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Lipid bilayers form the basis of organellar architecture, structure, and compartmentalization in the cell. Decades of biophysical, biochemical, and imaging studies on purified or in vitro-reconstituted liposomes have shown that variations in lipid composition influence the physical properties of membranes, such as thickness and curvature. However, similar studies characterizing these membrane properties within the native cellular context have remained technically challenging. Recent advancements in cellular cryo-electron tomography (cryo-ET) imaging enable high-resolution, three-dimensional views of native organellar membrane architecture preserved in near-native conditions. We previously developed a "Surface Morphometrics" pipeline that generates surface mesh reconstructions to model and quantify cellular membrane ultrastructure from cryo-ET data. Here, we expand this pipeline to measure the distance between the phospholipid head groups of the membrane bilayer as a readout of membrane thickness. Using this approach, we demonstrate thickness variations both within and between distinct organellar membranes. We show that organellar membrane thickness positively correlates with other features, such as membrane curvedness, in cells. Further, we show that subcompartments of the mitochondrial inner membrane exhibit varying membrane thicknesses that are independent of whether the mitochondria are in fragmented or elongated networks. We also demonstrate that our technique, when applied to three-dimensional data, yields results that match existing measurements obtained from two-dimensional data of in vitro samples. Finally, we demonstrate that large membrane-associated macromolecular complexes exhibit distinct density profiles that correlate with local variations in membrane thickness. Overall, our updated Surface Morphometrics pipeline provides a framework for investigating how changes in membrane composition in various cellular and disease contexts affect organelle ultrastructure and function.

Keywords

Cryoelectron Microscopy, Electron Microscope Tomography, Mitochondrial Membranes, Lipid Bilayers, Mitochondria, Cell Membrane, Humans, Organelles

Published Open-Access

yes

Recommended Citation

Medina, Michaela; Chang, Ya-Ting; Rahmani, Hamidreza; et al., "Surface Morphometrics Reveals Local Membrane Thickness Variation in Organellar Subcompartments" (2026). Faculty, Staff and Student Publications. 3737.
https://digitalcommons.library.tmc.edu/uthmed_docs/3737