MRI biosensor for protein kinase A encoded by a single synthetic gene
Article first published online: 28 SEP 2012
Copyright © 2012 Wiley Periodicals, Inc.
Magnetic Resonance in Medicine
Volume 68, Issue 6, pages 1919–1923, December 2012
How to Cite
Airan, R. D., Bar-Shir, A., Liu, G., Pelled, G., McMahon, M. T., van Zijl, P. C. M., Bulte, J. W. M. and Gilad, A. A. (2012), MRI biosensor for protein kinase A encoded by a single synthetic gene. Magn Reson Med, 68: 1919–1923. doi: 10.1002/mrm.24483
- Issue published online: 21 NOV 2012
- Article first published online: 28 SEP 2012
- Manuscript Accepted: 13 AUG 2012
- Manuscript Revised: 10 AUG 2012
- Manuscript Received: 6 JUL 2012
- NIH. Grant Numbers: EB008769, NS065284, EB005252, EB012590, EB006394, NS072171, EB015032
- chemical exchange saturation transfer;
- reporter gene;
- protein kinase A
Protein kinases including protein kinase A (PKA) underlie myriad important signaling pathways. The ability to monitor kinase activity in vivo and in real-time with high spatial resolution in genetically specified cellular populations is a yet unmet need, crucial for understanding complex biological systems as well as for preclinical development and screening of novel therapeutics.
Using the hypothesis that the natural recognition sequences of protein kinases may be detected using chemical exchange saturation transfer magnetic resonance imaging, we designed a genetically encoded biosensor composed of eight tandem repeats of the peptide LRRASLG, a natural target of PKA.
This sensor displays a measurable change in chemical exchange saturation transfer signal following phosphorylation by PKA. The natural PKA substrate LRRASLG exhibits a chemical exchange saturation transfer-magnetic resonance imaging contrast at +1.8 and +3.6 ppm, with a >50% change after phosphorylation with minutes-scale temporal resolution. Expression of a synthetic gene encoding eight monomers of LRRASLG yielded two peaks at these chemical exchange saturation transfer frequencies.
Taken together, these results suggest that this gene may be used to assay PKA levels in a biologically relevant system. Importantly, the design strategy used for this specific sensor may be adapted for a host of clinically interesting protein kinases. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.