BMG Labtech has published an Application Note on the use of ita PHERAstar plate reader for monitoring cellular insulin granules.
Diabetes mellitus is a metabolic disease arising from resistance to insulin or limited insulin secretion. The high prevalence of diabetes means that studying modulators of insulin production and storage is highly demanded.
In the course of insulin secretion, the hormone is packed into vesicles, leading to a high insulin density. This is exploited for measuring granular insulin using the fluorescently labelled hormone. Highly concentrated fluorophores of the same type are able to undergo resonance energy transfer (homo-FRET). Polarised excitation light results in randomised emission in case energy was transferred to a neighboring fluorophore (homo-FRET-FP).
The application note shows that detecting homo-FRET-FP of mCherry labelled insulin with the PHERAstar allows for monitoring of cellular insulin-granules in 384 well plate format. Preventing vesicle formation decreases the FP value, representing lower local
mCherry-insulin concentrations and accordingly less emission light randomisation.
