Lighting Up Ageing Cells: NTU Researchers Develop a Novel Biosensor to Study Actin Dynamics
How do our cells adapt to stress and age over time? A research team from the School of Biological Sciences (SBS) has developed a new biosensor that makes it possible to observe the “age” of certain cell structures for the first time.
Published in the Proceedings of the National Academy of Sciences (PNAS) in July 2025, the study introduces ADPact, a novel 20-amino-acid peptide that selectively binds to ADP-bound F-actin – a form of the actin cytoskeleton that accumulates during cellular stress and ageing. This breakthrough research was led by Professor Miao Yansong, with Dr Qianqian Ma as first author, and supported by SBS researchers Xiao Han, Kexin Zhu, Cai Xin Ng, and Danxia He.
What is Actin and Why Does It Matter?
Actin filaments (F-actin) are dynamic protein structures that maintain the cell’s shape, drive movement, and support many essential intracellular processes. As cells experience stress or undergo ageing, actin filaments shift from a fresh, ATP-bound state to an aged, ADP-bound state, reflecting changes in their energy and functional status.
Until now, researchers lacked a tool to distinguish these nucleotide states in living cells. Conventional probes such as Phalloidin and Lifeact label F-actin in general but cannot differentiate between the ADP- and ATP-bound forms, limiting insights into cytoskeletal remodelling during stress or ageing.
The Discovery: ADPact
ADPact fills this gap. This new biosensor acts like a precision spotlight, specifically recognising aged, ADP-bound F-actin. It enables scientists to visualise the spatial and temporal distribution of these filaments in live cells – and monitor how they reorganise in response to metabolic changes, energy depletion, or oxidative stress.
The team confirmed that ADPact binds specifically and selectively to ADP-F-actin both in vitro and in live-cell imaging, making it a unique and powerful research tool.
The Future of Ageing Research: Implications for Biomedical Science
By enabling selective visualisation of aged actin filaments, ADPact opens up new possibilities in the study of cytoskeletal dynamics, cellular ageing, and disease mechanisms. A better understanding of how the actin cytoskeleton adapts to energy and environmental stresses could inform new strategies for tackling age-related diseases and degenerative conditions.
Patent applications have been filed in both the US and Europe for ADPact, reflecting its scientific novelty and translational potential.
This milestone underscores the strength of SBS in advancing foundational biomedical research. Congratulations to our researchers for this pioneering contribution to cell biology and ageing science!
Read the full paper here.