DNA Nanodevices Reveal Acidic Nanolayer on Lysosome Surfaces in Live Cells

Why It Matters

Identifying the juxta‑lysosomal pH gradient reshapes our understanding of how luminal acidity controls organelle dynamics and opens new therapeutic targets for neurodegenerative diseases.

Key Takeaways

• DNA nanodevices quantify juxta‑lysosomal pH in live cells
• Acidic nanolayer up to 21 nm coats lysosome surface
• TMEM175 channel creates and sustains the acidic layer
• RILP senses pH_jx‑LY to drive retrograde transport
• Enhanced acidity links to Parkinson’s disease lysosomal dysfunction

Pulse Analysis

The inability to probe the cytosolic side of lysosomes has long limited cell‑biology research, as most pH sensors target the organelle lumen. By engineering ratiometric DNA nanodevices that tether to the outer membrane, scientists now obtain real‑time, quantitative readouts of juxta‑lysosomal acidity without disrupting native trafficking. This methodological breakthrough not only overcomes the spatial resolution barrier of conventional fluorophores but also provides a versatile platform adaptable to other membrane‑bound organelles, expanding the toolkit for intracellular microenvironment monitoring.

The study reveals that every lysosome is surrounded by a thin, acidic nanolayer—up to 21 nm thick—maintained primarily by the proton‑conducting channel TMEM175. This external pH gradient, rather than the well‑characterized intralysosomal pH, directly modulates the activity of the Rab7‑RILP dynein adaptor, steering lysosomes toward the microtubule‑minus end. Consequently, cells can fine‑tune organelle positioning in response to nutrient cues, and the acidic surface also promotes lysosome‑ER membrane contact site formation, linking pH dynamics to broader inter‑organelle communication networks.

In Parkinson’s‑disease models, neurons exhibit a markedly more acidic juxta‑lysosomal environment, correlating with aberrant lysosome distribution and impaired autophagic flux. This connection positions the acidic nanolayer as a potential biomarker and therapeutic entry point; modulating TMEM175 activity or RILP‑mediated sensing could restore normal lysosomal trafficking and mitigate neurodegeneration. Future investigations are likely to explore small‑molecule regulators of the nanolayer and extend the DNA‑nanodevice approach to study pH‑dependent processes across diverse cellular contexts, heralding a new era of precision organelle biology.