Research method
Electron Microscopy
5 studies
Electron microscopy uses an electron beam to image ultrastructure — caveolar coats, membranes, lipid droplets, or (in related structural work) packed protein contacts — at nanometre-scale resolution. The output is a morphology or a reconstructed density, not a live itinerary of a vesicle and not a gene-expression table. Sample preparation (fixation, staining, cryo) is part of what you are seeing.
Trafficking papers reach for EM when light microscopy cannot resolve coat architecture or membrane topology. It answers 'what does this complex or organelle look like at high resolution?' Its main limitation is that static ultrastructure is not dynamics, and several papers tagged here are really live confocal, microarray, or GPCR contact analysis of deposited structures rather than a cell-biology EM experiment on the same question.
Studies
5
Findings
5
5 supporting · 0 challenging · 0 qualifying citations
Open tensions
2
Currently
What we know
- Caveolar-coat purification plus ultrastructure showed caveolins and cavins as one complex excluding EHD2/pacsin 2, with Cavin 1 a core component and evidence for trimers. EM here supports a coat model; it is not a full in-vivo dynamics movie of every cell type.
- APEX2 proximity maps of cytosol-facing OMM (22 proteins) and ERM (72 proteins) are mass-spectrometry inventories that may use EM only to confirm organelle context. The headline result is enrichment beyond classical fractionation, not an ultrastructural atlas of every new protein.
- Class A GPCR activation was inferred from residue–residue contact scores across 142 inactive and 27 active structures (p<0.001), yielding a 34-residue-pair pathway across layers. That is comparative structural biology on deposited structures (often crystallography or cryo-EM of isolated receptors), not a trafficking EM study of endosomes, and it does not replace ligand-specific pharmacology.
- Atlantic salmon adipose stromal-vascular cultures were induced to adipogenesis and profiled by microarray: early MSC/immune/perivascular signatures gave way to lipid-accumulating adipocyte phenotypes by day 30. EM of lipid droplets, if used, is a differentiation check; in-vitro culture may not match in-vivo adipose niches.
- Bacteroides thetaiotaomicron OMVs entered epithelial cells and organoids within about 15 minutes via dynamin-dependent endocytosis or macropinocytosis, then reached Golgi/ER/nucleus routes and lysosomes. That itinerary is live imaging with inhibitors and organelle markers — confocal-scale trafficking — not a proof of every systemic human effect, and not primarily transmission-EM reconstruction.
Largest unresolved question
Only the caveolar paper is clearly an ultrastructure-of-a-coat study. GPCR work compares 142 inactive and 27 active deposited structures; APEX2 is proteomics; salmon work is a 30-day transcriptome of fat-cell differentiation; Bt OMV uptake is live light-microscopy trafficking. Calling all five 'electron microscopy papers' overstates shared methods.
Common misconceptions
If EHD2 and pacsin 2 appear near caveolae, ultrastructure has placed them in the caveolin–cavin coat.
Quantitative composition plus ultrastructure put caveolins and cavins in one complex that excludes EHD2/pacsin 2, with Cavin 1 core and trimeric. Nearby is not in-coat.
A shared 34-residue-pair GPCR activation path means every class A ligand can be ignored.
Contact scores across 142 inactive and 27 active structures (p<0.001) describe a conserved switching pathway. The authors do not replace ligand-specific pharmacology for every receptor.
OMV uptake imaged in 15 minutes is an electron-microscopy proof of human systemic vesicle effects.
The assays are live imaging and trafficking with endocytosis inhibitors in epithelial cells/organoids. Systemic human effects are not proven, and the design is not classic cell-section EM.
Related
Claim ledger
What the evidence shows
Drawn from 5 studies in this library. Mix labels say which citation roles are present; they are not a strength score. Supports means evidence for a finding; Challenges means evidence against a stated position; Qualifies marks scope.
Caveolar-coat purification plus ultrastructure showed caveolins and cavins as one complex excluding EHD2/pacsin 2, with Cavin 1 a core component and evidence for trimers. EM here supports a coat model; it is not a full in-vivo dynamics movie of every cell type.
APEX2 proximity maps of cytosol-facing OMM (22 proteins) and ERM (72 proteins) are mass-spectrometry inventories that may use EM only to confirm organelle context. The headline result is enrichment beyond classical fractionation, not an ultrastructural atlas of every new protein.
Class A GPCR activation was inferred from residue–residue contact scores across 142 inactive and 27 active structures (p<0.001), yielding a 34-residue-pair pathway across layers. That is comparative structural biology on deposited structures (often crystallography or cryo-EM of isolated receptors), not a trafficking EM study of endosomes, and it does not replace ligand-specific pharmacology.
Atlantic salmon adipose stromal-vascular cultures were induced to adipogenesis and profiled by microarray: early MSC/immune/perivascular signatures gave way to lipid-accumulating adipocyte phenotypes by day 30. EM of lipid droplets, if used, is a differentiation check; in-vitro culture may not match in-vivo adipose niches.
Bacteroides thetaiotaomicron OMVs entered epithelial cells and organoids within about 15 minutes via dynamin-dependent endocytosis or macropinocytosis, then reached Golgi/ER/nucleus routes and lysosomes. That itinerary is live imaging with inhibitors and organelle markers — confocal-scale trafficking — not a proof of every systemic human effect, and not primarily transmission-EM reconstruction.
Debates
Tensions and limits
Some items are genuine disagreements on the same question. Others mark different assays, populations, or outcomes.
Only the caveolar paper is clearly an ultrastructure-of-a-coat study. GPCR work compares 142 inactive and 27 active deposited structures; APEX2 is proteomics; salmon work is a 30-day transcriptome of fat-cell differentiation; Bt OMV uptake is live light-microscopy trafficking. Calling all five 'electron microscopy papers' overstates shared methods.
Only the caveolar paper is clearly an ultrastructure-of-a-coat study. GPCR work compares 142 inactive and 27 active deposited structures; APEX2 is proteomics; salmon work is a 30-day transcriptome of fat-cell differentiation; Bt OMV uptake is live light-microscopy trafficking. Calling all five 'electron microscopy papers' overstates shared methods.
- What proteins build the caveolar coat?
- Shared class A GPCR activation path
- Mapping the faces of mitochondria and ER
- Salmon fat-cell differentiation transcriptome
- How do gut-bacteria vesicles enter host cells?
Study Role Design N Population Outcome What proteins build the caveolar coat? Supports Animal / in-vitroBiochemical purification and ultrastructure of caveolar coat proteins Structural/biochemical coat stoichiometry study — no single sample N Caveolar coat complexes (caveolins/cavins) Molecular composition and ultrastructure of the caveolar coat Shared class A GPCR activation path Supports Computational / modellingResidue–residue contact score comparison across inactive and active Class A GPCR structures N=169 · 142 inactive and 27 active structures compared Class A GPCR crystal/cryo-EM structures Conserved 34-residue-pair activation contact pathway Mapping the faces of mitochondria and ER Supports Animal / in-vitroAPEX2 proximity labeling of cytosol-facing OMM and ER membranes in living HEK 293T cells SILAC proteomic maps with two replicates per membrane — cell-resource study HEK 293T cells expressing OMM/ERM APEX2 fusions Proteomes of cytosol-facing outer mitochondrial and ER membranes Salmon fat-cell differentiation transcriptome Supports Animal / in-vitroMicroarray time course of cultured salmon adipose-derived stromo-vascular cells during adipogenesis In-vitro differentiation days 1–30; no single primary animal analytic N in stored text Atlantic salmon adipose-derived stromo-vascular fraction cultures Gene-expression trajectory from MSC-like cells to mature adipocytes How do gut-bacteria vesicles enter host cells? Supports Animal / in-vitroLive imaging of B. thetaiotaomicron OMVs on intestinal epithelial cells/organoids Cell/organoid trafficking assays — no single primary analytic N in stored text Intestinal epithelial cells and organoids exposed to Bt OMVs Uptake routes and intracellular biodistribution of bacterial OMVs
PaperFren reads this as a limit on how far one study travels — different assays, populations, or outcomes — not a forced fight between papers.
Resolution targets disagree. Caveolar EM asks about coat stoichiometry (Cavin 1 trimers; exclusion of EHD2/pacsin 2). GPCR contact maps ask about conserved switches across receptors (34 residue pairs). OMV live imaging asks about a 15-minute endocytic route. Those answers cannot substitute for one another.
Resolution targets disagree. Caveolar EM asks about coat stoichiometry (Cavin 1 trimers; exclusion of EHD2/pacsin 2). GPCR contact maps ask about conserved switches across receptors (34 residue pairs). OMV live imaging asks about a 15-minute endocytic route. Those answers cannot substitute for one another.
- What proteins build the caveolar coat?
- Shared class A GPCR activation path
- How do gut-bacteria vesicles enter host cells?
Study Role Design N Population Outcome What proteins build the caveolar coat? Supports Animal / in-vitroBiochemical purification and ultrastructure of caveolar coat proteins Structural/biochemical coat stoichiometry study — no single sample N Caveolar coat complexes (caveolins/cavins) Molecular composition and ultrastructure of the caveolar coat Shared class A GPCR activation path Supports Computational / modellingResidue–residue contact score comparison across inactive and active Class A GPCR structures N=169 · 142 inactive and 27 active structures compared Class A GPCR crystal/cryo-EM structures Conserved 34-residue-pair activation contact pathway How do gut-bacteria vesicles enter host cells? Supports Animal / in-vitroLive imaging of B. thetaiotaomicron OMVs on intestinal epithelial cells/organoids Cell/organoid trafficking assays — no single primary analytic N in stored text Intestinal epithelial cells and organoids exposed to Bt OMVs Uptake routes and intracellular biodistribution of bacterial OMVs
PaperFren reads this as a limit on how far one study travels — different assays, populations, or outcomes — not a forced fight between papers.
Timeline
How understanding moved
Study years are when the paper was published. Evidence edits are dated changes to this page's claims. Explanations are when PaperFren added a Discovery — not a claim that the science happened that day.
2026
Concept page published
Electron Microscopy
Change log
What changed
Dated edits to this page's evidence: studies added or removed from a claim, claims added or withdrawn, and new explanations tagged here. Coverage edits are distinct from reviewed research changes and corrections. Dates record PaperFren updates; study publication dates appear in the timeline.
- Coverage updated · Concept page published
Papers
5 studies in this library bear on Electron Microscopy, ordered by citations.
- Shared class A GPCR activation path
Class A GPCRs share a conserved residue-contact rearrangement pathway from ligand pocket to G-protein site.
- Mapping the faces of mitochondria and ER
APEX2 proximity biotinylation yields high-quality proteomic maps of cytosol-facing outer mitochondrial and ER membranes in living human cells.
- How do gut-bacteria vesicles enter host cells?
B. thetaiotaomicron outer-membrane vesicles are taken up within minutes via dynamin-dependent endocytosis/macropinocytosis and traffic to Golgi/ER/lysosomes.
- What proteins build the caveolar coat?
Caveolins and cavins purify as a caveolar coat complex with Cavin 1 as a core trimeric component.
- Salmon fat-cell differentiation transcriptome
Atlantic salmon adipose SVF cells progress through proliferative then adipogenic expression programs.
Compare studies
Select 2–10 studies. Design and N are labels, not a ranking.
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Questions
What is still open
Only the caveolar paper is clearly an ultrastructure-of-a-coat study. GPCR work compares 142 inactive and 27 active deposited structures; APEX2 is proteomics; salmon work is a 30-day transcriptome of fat-cell differentiation; Bt OMV uptake is live light-microscopy trafficking. Calling all five 'electron microscopy papers' overstates shared methods.
Resolution targets disagree. Caveolar EM asks about coat stoichiometry (Cavin 1 trimers; exclusion of EHD2/pacsin 2). GPCR contact maps ask about conserved switches across receptors (34 residue pairs). OMV live imaging asks about a 15-minute endocytic route. Those answers cannot substitute for one another.
Ask PaperFren about Electron Microscopy
Study this conceptflashcards and short-answer questions
Caveolar ultrastructure excludes EHD2/pacsin 2 from the caveolin–cavin coat. What biochemical measurement has to agree with the EM for that claim to stick?
Quantitative composition of the purified coat showing those proteins absent from the complex, with Cavin 1 core and trimers. EM morphology without stoichiometry could still be misread as 'all caveola-associated proteins are coat subunits'.
Why is comparing 142 inactive and 27 active GPCR structures a different 'microscopy' claim than imaging Bt OMV endocytosis?
The GPCR paper scores residue contacts on deposited high-resolution structures (p<0.001; 34-pair pathway). OMV work times uptake (~15 min) and routes (dynamin/macropinocytosis to Golgi/ER/lysosomes) in cells. One is structural comparison; the other is live trafficking.
Salmon aSVF cultures show lipid-accumulating phenotypes by day 30. What can EM of droplets add, and what can microarray still not claim?
EM can confirm lipid-droplet ultrastructure of the differentiated state. The expression trajectory is in-vitro and may not match in-vivo adipose niches.
APEX2 found 22 OMM and 72 ERM proteins. If a figure includes an electron micrograph of mitochondria, why is the paper still not primarily an EM method study?
The maps are proximity biotinylation plus mass spectrometry in living cells. An EM image may document organelle integrity; it does not functionally validate each enriched protein or replace the proteomic inventory.