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Compressive Force Activation of the Neuronal Nitric Oxide Synthase Enzyme
Lalita Shahu1, Yadav Prasad Gyawali2, Ting Jiang2
1Center for Photochemical Sciences, Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States.
ACS Omega
|September 15, 2025
Summary
External force can activate nitric oxide (NO) production by neuronal nitric oxide synthase (nNOS) using calcium-free calmodulin (apo-CaM) as a mechanosensor. This study demonstrates force-induced NO release via apo-CaM-nNOS interaction.
Area of Science:
- Biochemistry
- Cellular Biology
- Biophysics
Background:
- Calmodulin (CaM) is a calcium-binding protein crucial for regulating nitric oxide (NO) production by nitric oxide synthase (NOS).
- While calcium-bound CaM activates NOS, the role of calcium-free CaM (apo-CaM) in NO biosynthesis, especially under mechanical stress, remains underexplored.
- NO is a vital intercellular signaling molecule involved in numerous physiological processes.
Purpose of the Study:
- To investigate the mechanism of NO production by neuronal NOS (nNOS) activated by apo-CaM under external mechanical force.
- To demonstrate that apo-CaM can function as a mechanosensor to modulate nNOS activity.
Main Methods:
- Utilized atomic force microscopy (AFM)-correlated confocal microscopy to probe NO production.
- Employed compressive force to manipulate apo-CaM.
- Used DAR-4M as a fluorescent probe for NO detection.
Main Results:
- Compressive force applied to apo-CaM induced conformational changes.
- These force-induced changes in apo-CaM facilitated binding and activation of the nNOS enzyme.
- Demonstrated NO production by nNOS activated by apo-CaM under external force.
Conclusions:
- Apo-CaM can act as a mechanosensing protein, translating mechanical force into biochemical signaling.
- External force can directly activate NO production through the apo-CaM-nNOS pathway.
- This finding offers new insights into the mechanical regulation of NO signaling.
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