title: A G-protein subunit translocation embedded network motif underlies GPCR regulation of calcium oscillations.
abstract: G-protein βγ subunits translocate reversibly from the plasma membrane to internal membranes on receptor activation. Translocation rates differ depending on the γ subunit type. There is limited understanding of the role of the differential rates of Gβγ translocation in modulating signaling dynamics in a cell. Bifurcation analysis of the calcium oscillatory network structure predicts that the translocation rate of a signaling protein can regulate the damping of system oscillation. Here, we examined whether the Gβγ translocation rate regulates calcium oscillations induced by G-protein-coupled receptor activation. Oscillations in HeLa cells expressing γ subunit types with different translocation rates were imaged and quantitated. The results show that differential Gβγ translocation rates can underlie the diversity in damping characteristics of calcium oscillations among cells. Mathematical modeling shows that a translocation embedded motif regulates damping of G-protein-mediated calcium oscillations consistent with experimental data. The current study indicates that such a motif may act as a tuning mechanism to design oscillations with varying damping patterns by using intracellular translocation of a signaling component.
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Lopamudra
authors.initials: L
authors.lastname: Giri
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India.
authors.forename: Anilkumar K
authors.initials: AK
authors.lastname: Patel
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: W K Ajith
authors.initials: WK
authors.lastname: Karunarathne
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Vani
authors.initials: V
authors.lastname: Kalyanaraman
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India. Electronic address: venks@iitb.ac.in.
authors.forename: K V
authors.initials: KV
authors.lastname: Venkatesh
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Department of Genetics, Washington University School of Medicine, St. Louis, Missouri. Electronic address: gautam@wustl.edu.
authors.forename: N
authors.initials: N
authors.lastname: Gautam
mesh_terms: D020013:Calcium Signaling; D002462:Cell Membrane / Q000378:metabolism; D025461:Feedback, Physiological; D044387:GTP-Binding Protein beta Subunits / Q000737:chemistry / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological
chemical_list: C118981:G-protein Beta gamma; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits