Protein Nanoparticles Engineered To Sense Kinase Activity In Mri

摘要

Magnetic resonance imaging (MRI) is a unique tool for analyzing biological specimens because it can be applied noninvasively, in living organisms, at high spatial and temporal resolution. The range of phenomena accessible to evaluation by MRI is limited, however, by a lack of molecular imaging agents capable of dynamically sensing specific physiological events. Most MRI sensors have incorporated synthetic contrast-generating moieties in complex structures or supramolecular assemblies that are often difficult to design, produce, and deliver in vivo. Here we introduce a family of completely protein-based nanoparticle MRI sensors that addresses these limitations. The new sensors are derived from the iron storage protein ferritin (Ft); they are designed and optimized using facile protein engineering methods, and self-assembled in cells harboring specific combinations of DNA coding sequences. As illustration, we show that suitably constructed Ft-based nanoparticle sensors can report the activity of the important neural signaling enzyme protein kinase A (PKA).