title: Band-pass processing in a GPCR signaling pathway selects for NFAT transcription factor activation.
abstract: Many biological processes are rhythmic and proper timing is increasingly appreciated as being critical for development and maintenance of physiological functions. To understand how temporal modulation of an input signal influences downstream responses, we employ microfluidic pulsatile stimulation of a G-protein coupled receptor, the muscarinic M3 receptor, in single cells with simultaneous real-time imaging of both intracellular calcium and NFAT nuclear localization. Interestingly, we find that reduced stimulation with pulses of ligand can give more efficient transcription factor activation, if stimuli are timed appropriately. Our experiments and computational analyses show that M3 receptor-induced calcium oscillations form a low pass filter while calcium-induced NFAT translocation forms a high pass filter. The combination acts as a band-pass filter optimized for intermediate frequencies of stimulation. We demonstrate that receptor desensitization and NFAT translocation rates determine critical features of the band-pass filter and that the band-pass may be shifted for different receptors or NFAT dynamics. As an example, we show that the two NFAT isoforms (NFAT4 and NFAT1) have shifted band-pass windows for the same receptor. While we focus specifically on the M3 muscarinic receptor and NFAT translocation, band-pass processing is expected to be a general theme that applies to multiple signaling pathways.
authors.affiliation: Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. takayama@umich.edu and Biophysics Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sumit
authors.affiliation: Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Neubig
authors.affiliation: Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. takayama@umich.edu and Michigan Centre for Integrative Research in Critical Care, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA.
authors.forename: S
authors.initials: S
authors.lastname: Takayama
authors.affiliation: Department of Biomedical Engineering, University of Michigan, 1107 Carl A. Gerstacker Building, 2200, Bonisteel Blvd, Ann Arbor, MI 48109, USA. linderma@umich.edu and Department of Chemical Engineering, University of Michigan, Building 26, 2800 Plymouth Road, Ann Arbor, MI 48109, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Linderman
mesh_terms: D021581:Active Transport, Cell Nucleus; D019540:Area Under Curve; D002118:Calcium / Q000378:metabolism; D003198:Computer Simulation; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D044085:Microfluidics; D008962:Models, Theoretical; D050778:NFATC Transcription Factors / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D008024:Ligands; D050778:NFATC Transcription Factors; C494006:NFATC2 protein, human; C494008:NFATC3 protein, human; D043562:Receptors, G-Protein-Coupled; D002118:Calcium