What question did this study set out to answer?

The aim is to visualize the distribution and 3D orientation of cardiac ryanodine receptors (RyR2) at sub-molecular resolution.

January 10, 2026Nature Communications0 citationsOpen Access

MINFLUX microscopy resolves subunits of the cardiac ryanodine receptor and its 3D orientation in cells

Q: What does this research mean for the field?

3D MINFLUX microscopy reveals that RyR2 subunits in cardiomyocytes form large clusters, resolving discrepancies with previous imaging techniques. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

ACAlexander H. ClowsleyUniversity of Bern AMAnna MeletiouUniversity of Bern RJRadoslav JaníčekElectrophysiology

Key Result

3D MINFLUX microscopy revealed that RyR2 subunits in cardiomyocytes form large clusters, resolving discrepancies with previous imaging techniques.

Key Points

The aim is to visualize the distribution and 3D orientation of cardiac ryanodine receptors (RyR2) at sub-molecular resolution.
Applied 3D MINFLUX microscopy for high-precision imaging.
Used single-domain antibodies and DNA-PAINT for localization of RyR2 subunits.
Investigated RyR2 expression in HEK293 cells and mouse ventricular myocytes.
Detected individual RyR2 subunits with ~3 nm resolution.
Achieved ~50% labeling efficiency, with a ~95% detection probability for RyR2 tetramers.
Resolved discrepancies with previous imaging techniques by demonstrating large clusters of RyR2 in cardiac cells.

Structured PICO

Population

HEK293 cells expressing RyR2 and ventricular myocytes from mice

Intervention

3D MINFLUX microscopy using single-domain antibodies and DNA-PAINT

Outcome

Location of individual RyR2 subunits and their 3D orientations in-situ

3D MINFLUX microscopy enables sub-molecular resolution imaging of cardiac ryanodine receptors, revealing their complex 3D morphology and clustering in cells.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Abstract The cardiac ryanodine receptor (RyR2) constitutes the molecular basis of the process of calcium-induced calcium release where activation of RyR2s can be locally regenerative. Here, we present purely optical data of RyR2 distribution with sub-molecular resolution by applying 3D MINFLUX microscopy. Using single-domain antibodies and DNA-PAINT we determine the location of individual RyR2 subunits with high precision (~3 nm) and resolve the 3D orientations of RyR2s in-situ. We measured labeling efficiencies of ~50%, implying RyR2 tetramer detection probability approaching 95%. In HEK293 cells, RyR2 expression was dense, with some clusters containing several hundred RyR2s. Ventricular myocytes from mice contained large clusters containing many tens of close-packed RyR2s, resolving apparent discrepancies between electron microscopy and previous super-resolution microscopy data. The methodology developed here reveals the full 3D morphological complexity of RyR2 channels and is applicable to other multi-subunit complexes in a variety of cell types.

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