Band-pass processing in a GPCR signaling pathway selects for NFAT transcription factor activation

Area of Science:

• Cellular signaling and systems biology
• Biophysics of cellular responses
• Molecular mechanisms of gene regulation

Background:

• Biological processes often exhibit rhythmic patterns crucial for development and physiological function.
• Understanding how signal timing impacts cellular responses is vital for deciphering complex biological systems.

Purpose of the Study:

• To investigate the influence of temporal stimulation patterns on downstream cellular responses.
• To characterize the filtering properties of signaling pathways involving G-protein coupled receptors and transcription factor activation.

Main Methods:

• Utilized microfluidic pulsatile stimulation of the muscarinic M3 receptor in single cells.
• Performed simultaneous real-time imaging of intracellular calcium dynamics and NFAT (nuclear factor of activated T-cells) nuclear localization.
• Employed computational analyses to model signaling pathway dynamics.

Main Results:

• Discovered that optimally timed, reduced stimulation pulses can lead to more efficient transcription factor activation.
• Demonstrated that M3 receptor-mediated calcium signaling acts as a low-pass filter, while calcium-induced NFAT translocation functions as a high-pass filter.
• Showed that the combined signaling pathway operates as a band-pass filter, favoring intermediate stimulation frequencies.

Conclusions:

• Receptor desensitization and NFAT translocation kinetics dictate the characteristics of the observed band-pass filter.
• The band-pass filtering properties can be modulated by different receptors or NFAT isoforms, as exemplified by NFAT4 and NFAT1.
• Band-pass processing is likely a general signaling principle applicable to various cellular pathways beyond the studied M3 receptor-NFAT system.