Dr. Albert Goldbeter, Université libre de Bruxelles

Abstract: Rhythmic behavior occurs at all levels of biological organization. After a brief review of biochemical and cellular rhythms, I will examine the oscillatory dynamics of the major regulatory networks that control, respectively, the circadian clock and the cell cycle. Models show how circadian rhythms occur in constant environmental conditions in the form of limit cycle oscillations, which can be entrained by the light-dark cycle. The model for the mammalian circadian clock accounts for the occurrence of different types of human sleep disorder. On the other hand, an experimentally based model for the mammalian cell cycle shows how the ordered progression through the successive cell cycle phases is driven by oscillations in the activity of a network of cyclin-dependent kinases. Experiments indicate that the circadian clock and the cell cycle are linked through bidirectional coupling. The dynamical consequences of such coupling have been studied by merging models for the mammalian circadian clock and for the network of cyclin-dependent kinases that drives the mammalian cell cycle. Compared to unidirectional coupling, which results in the entrainment of one oscillator by the other, bidirectional coupling enhances the robust synchronization of the two cellular rhythms. The model further predicts the possibility of multi-synchronization, i.e., the coexistence between multiple modes of synchronized oscillations characterized by different amplitudes and periods.

Bio: Dr. Albert Goldbeter is honorary professor in the Faculty of Sciences at Université Libre de Bruxelles (ULB), Brussels, Belgium. His research primarily pertains to modeling the mechanism of a variety of biochemical and cellular rhythms, including glycolytic oscillations, oscillations in Calcium and cyclic AMP signaling, the segmentation clock, circadian rhythms, and the cell cycle. Dr. Albert Goldbeter held visiting research professorships at the University of California at Berkeley (Miller Institute), the Universities of Paris VI and Paris-Sud Orsay, Fudan University (Shanghai), Nanjing Agricultural University, and Soochow University (Suzhou). He is author of the books Biochemical Oscillations and Cellular Rhythms. The molecular bases of periodic and chaotic behaviour (Cambridge University Press, 1996), and Oscillatory Life, Mechanisms and functions of biological rhythms (Springer, 2027, in press).