Fluorescent Sensors of Protein Kinases: From Basics to Biomedical Applications - Progress in Molecular Biology and Translational Science - page 258

4. APPLICATIONS
Protein kinases are central to most biological signaling pathways and
constitute disease biomarkers in many pathological conditions. As such, they
have been the focus of intensive studies using different technologies, mostly
based on antigenic and radioactive assays. The more recent development of
fluorescent reporters and biosensors has provided the means of imaging the
activity and dynamic behavior of protein kinases in real time in their natural
environment, with high spatial and temporal resolution, without perturbing
their native structure or function. Fluorescent biosensors provide a wealth of
opportunities over other approaches used for fundamental studies of protein
kinases and allow for countless practical applications in analytical chemistry
and biotechnology, as well as in biomedical and drug discovery programs
( Fig. 6.15 ).
4.1. Fundamental studies of protein kinase localization,
function, and regulation
From a fundamental perspective, fluorescent biosensors have proved useful
for studying the dynamics of subcellular localization, function, and regula-
tion of individual kinases in real time. While these tools may be employed to
study the kinetics of protein kinase activation in vitro , they may equally well
be used to probe associated activities in cell extracts and further be applied to
characterize the spatiotemporal dynamics and activities of these enzymes in
living cells with high spatial and temporal resolution. Biosensor technology
allows addressing those aspects of protein kinase biology that had not been
characterized previously because of the lack of appropriate technologies.
Indeed, fluorescent biosensors allow imaging the behavior of protein kinases
within distinct subcellular compartments and, in response to stimuli,
involving different cofactors, agonists, or coregulators, thereby contributing
to unravel complex signaling cascades that lead to kinase activation in a
physiological context and providing a comprehensive understanding of their
overall function in a cellular context. Moreover, fluorescent biosensors
are very useful for comparative studies of protein kinases in healthy and
pathological conditions, highlighting molecular and cellular alterations
associated with disease in a qualitative and quantitative fashion (for review,
see Refs. 150-152 ).