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UID:0-909@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20230929T110000
DTEND;TZID=Europe/Paris:20230929T120000
DTSTAMP:20230921T170648Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i
 nterface-seminar-elisa-floris/
SUMMARY:Physics-Biology interface seminar: Elisa Floris - Moyen Amphi\, Bui
 lding 510\, Université Paris-Saclay Orsay - 29 Sep 23 11:00
DESCRIPTION:Statistical physics of molecular sorting in living cells\nJoint
  seminar with the Soft Matter group at LPS\nElisa Floris (Politecnico de T
 orino\, Italy)\nMolecular sorting is a fundamental process responsible for
  the organization of intracellular matter: biomolecules that dwell on the 
 outer and inner membranes of the cell are partitioned into spatially local
 ized domains and engulfed into small vesicles\, that detach from the membr
 ane to be delivered to their right destinations. A recently proposed theor
 etical model of this process is based on the coupling of a) phase-separati
 on-driven formation of sorting domains and b) domain-induced membrane bend
 ing\, leading to vesicle nucleation [1]. In this minimal model\, molecules
  are randomly inserted on the lipid membrane\, can diffuse laterally and a
 ggregate into domains\, and are extracted as part of a domain once it has 
 reached a characteristic extraction size\, representing the average size o
 f mature vesicles. The predictions of the theory and numerical investigati
 ons of a latticegas realization of the model show the existence of an opti
 mal region of parameter space where sorting is most efficient. In the expe
 riments\, detected domains are commonly classified into two groups: produc
 tive domains\, if their growth eventually terminates in the nucleation of 
 a vesicle\, and unproductive domains which rapidly dissolve. To interpret 
 these data\, we use central notions of the classical theory of phase separ
 ation\, such as the boundary tension and the critical domain size. Compari
 son with experimental results shows that the statistical properties of pro
 ductive and unproductive domains inferred from experimental data are in ag
 reement with those predicted from numerical simulations of the model\, com
 patibly with the hypothesis that molecular sorting is driven by a phase se
 paration process. The model is further extended to account for the simulta
 neous sorting of a multiplicity of molecular species\, revealing that\, wh
 en keeping fixed the total incoming molecular flux\, the average molecule 
 residence time increases with the heterogeneity of the molecular pool acco
 rding to a simple scaling law. Molecular sorting is further investigated b
 y means of a simplified one-dimensional lattice-gas model\, where the memb
 rane is allowed to undergo the topological transformations corresponding t
 o fusion and detachment of molecule-loaded vesicles.\n\nReferences\n[1] Ma
 rco Zamparo\, Donatella Valdembri\, Guido Serini\, Igor V Kolokolov\, Vlad
 imir V Lebedev\, Luca Dall’Asta\, and Andrea Gamba. Optimality in self-o
 rganized molecular sorting. Physical Review Letters\, 126(8):088101\, 2021
 .
CATEGORIES:physbio,seminars
LOCATION:Moyen Amphi\, Building 510\, Université Paris-Saclay Orsay\, 15 R
 ue Georges Clemenceau\, orsay\, France
GEO:48.698187;2.181768
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