Fluctuations, reactions and effective diffusion: from the description of the whole to that of the individual molecules

SILVINA PONCE DAWSON

Exposición; Seminarios del grupo de Probabilidad del DM-FCEN, UBA; 2015

The new microscopy techniques are allowing the direct observation ofthe intracellular dynamics with increasing precision. In particular,it is possible to "see" individual molecules at work and how thisbehavior gives rise to the collective output, the only one that couldbe measured in the past. These observations show a highly fluctuatingworld. In spite of this, cells act upon external stimuli producingprecise responses. In many occasions the information transmission thatyields to these responses involves the diffusion and binding ofmolecules to receptors. How does an individual molecule travelsinside the cell in such a case and how does this transport comparewith that of a bunch of them? How long does it take for an immobilereceptor that has a limited action radius to sense the bulkconcentration of its ligand? How do fluctuations in the sensingmechanisms impact on the eventual response. In this talk I will showsome of the results that we obtained when trying to answer thesequestions and comment on the difficulties that we encountered (andstill do!).