See Centrioles, Cilia and Flagella in Live Cells Without Genetic Engineering

CenSpark650: First-in-class dual-ligand fluorescent probe for selective imaging of centrioles and ciliary microtubules

Centrioles and cilia are essential organelles governing cell division, signalling, motility and immune function.
Despite their importance, studying their dynamics in live cells has remained technically restricted due to the lack of selective small-molecule probes.
Most existing approaches rely on genetic engineering or non-specific microtubule dyes, limiting their use in primary cells and non-model systems.

Key Challenges

Centrioles and cilia contain specialised microtubule architectures (triplets and doublets) that are absent from cytoplasmic microtubules.
However, no previously available small-molecule probe could selectively distinguish these structures in live cells.

As a result, researchers have been unable to:

Track centriole dynamics over time in native systems
Visualise cilia and flagella without genetic tagging
Study these organelles in genetically intractable organisms or primary human cells

Overview

Developed by Spirochrome, CenSpark650 is a cell-permeable small-molecule probe engineered to selectively recognise microtubule triplets and doublets found exclusively in centrioles and axonemes.

Its selectivity arises from a unique dual-binding mechanism targeting the spatially adjacent inner and outer microtubule binding sites of A- and B-tubules, a structural feature absent in cytoplasmic microtubules.

Key Benefits

Selective visualisation of centrioles, cilia and flagella across eukaryotes
No genetic modification required, enabling use in primary cells and non-model organisms
Live-cell compatible with low toxicity, supporting multi-day tracking of organelle dynamics
High spatial resolution imaging, including centriole positioning and cilium morphology
Validated in challenging systems, including human primary fibroblasts and immune cells
Enables dynamic studies previously inaccessible, including cilium assembly kinetics and immune synapse organisation

Key Features

Dual-ligand architecture bridging Taxol- and peloruside A-binding sites
Selective enrichment in microtubule triplets (centrioles) and doublets (cilia/flagella)
Strong signal stability and compatibility with live imaging workflows
Works across vertebrate, invertebrate and protist systems

Typical Applications

Centriole tracking during the cell cycle in live human cells
Primary cilium formation and elongation dynamics
Motile cilia and flagella imaging in algae (e.g. Chlamydomonas reinhardtii)
Ciliogenesis studies in primary human fibroblasts
Centriole repositioning during immune synapse formation in CAR-T cells
Single-cell interaction studies involving immune cell targeting dynamics

Additional Resource

Read the full peer-reviewed study in Nature Chemical Biology. Pourroy, C., Hatzopoulos, G.N., Reymond, L. et al. Development of the fluorescent probe CenSpark for labeling centrioles and cilia. Nat Chem Biol (2026). https://doi.org/10.1038/s41589-026-02186-1.

Imagen: CenSpark selectively binds microtubule doublets in vitro. a,b, Montage showing subtilisin-treated singlet microtubule (rhodamine, yellow) and doublet-like microtubule segments (HiL488, cyan), incubated with 2 nM SPY650-tubulin (a) or 2 nM CenSpark-650 (b) (both in magenta).

(Source: https://doi.org/10.1038/s41589-026-02186-1)