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UID:0-922@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20231110T110000
DTEND;TZID=Europe/Paris:20231110T120000
DTSTAMP:20231020T171141Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/physics-biology-i
 nterface-seminar-emmanuel-derivery/
SUMMARY:Physics-Biology interface seminar: Emmanuel Derivery - Salle des s
 éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 10 Nov 23 11:00
DESCRIPTION:Macromolecular condensation buffers intracellular water potenti
 al\nEmmanuel Derivery (Cambridge U.)\n\nOptimum protein function and bioch
 emical activity critically depends on water availability inside cells. Mac
 romolecules restrict the movement of “structured” water molecules in t
 heir hydration layers\, reducing the available “free” bulk solvent and
  therefore the total thermodynamic potential energy of water\, or water po
 tential. Within concentrated macromolecular solutions like the cytosol\, w
 e found that modest changes in temperature greatly impact the water potent
 ial. We predicted that lower temperatures would reduce the available “fr
 ee” intracellular water in a similar manner to external hyperosmotic con
 ditions\, and vice versa for higher temperatures and hypoosmotic condition
 s. We validated this duality of temperature and osmotic strength on cellul
 ar physiology: hypoosmotic conditions mimicked high temperature in thermos
 ensitive yeast mutants\, whereas cold temperatures induced chondrocyte Ca2
 + signalling similar to hyperosmotic conditions. Most remarkably\, simple 
 manipulations of solvent thermodynamics were sufficient to prevent cell de
 ath upon extreme cold or heat shock. Physiologically\, cells must sustain 
 their activity in the face of fluctuating temperature\, pressure and osmot
 ic strength that impact water potential within seconds\, but established m
 echanisms of water homeostasis act over much slower timescales\, so we pos
 tulated the existence of a rapid compensatory response. We find this funct
 ion is performed by water potential-driven changes in macromolecular assem
 bly\, particularly biomolecular condensation of intrinsically-disordered p
 roteins\, which is determined by the water potential rather than the conce
 ntration of any specific macromolecule. In cells\, formation or dissolutio
 n of biomolecular condensates counteracted thermal or osmotic perturbation
 s of water potential\, which was robustly buffered in isolated cytoplasm. 
 Our results indicate that biomolecular condensation constitutes an intrins
 ic biophysical feedback response that rapidly compensates for intracellula
 r osmotic and thermal fluctuations. We suggest preserving water availabili
 ty within the concentrated cytosol is an overlooked evolutionary driver of
  protein (dis)order and function.\n\n
CATEGORIES:physbio,seminars
LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53
 0\, rue André Riviere\, Orsay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\
 , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST 
 et du LPTMS\, bâtiment Pascal n°530:geo:0,0
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TZID:Europe/Paris
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DTSTART:20231029T020000
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