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SUMMARY:Simple Models for Liquid-Liquid Phase Separation in Biological Cel
 ls - Professor Halim Kusumaatmaja\, Durham University
DTSTART:20220302T143000Z
DTEND:20220302T153000Z
UID:TALK164002@talks.cam.ac.uk
CONTACT:Lisa Masters
DESCRIPTION:Recent years have seen a significant change in the way we view
  the intracellular environment. We now recognise the ubiquitous presence o
 f droplets or condensates composed of RNA and/or proteins that form throug
 h a phase separation like process. In this talk\, I will discuss several p
 roblems related to these condensates. First\, motivated by the fine compos
 itional control observed in membraneless droplet organelles in cells\, we 
 investigate how a sharp binding-unbinding transition can occur between mul
 tivalent client molecules and receptors embedded in a porous three-dimensi
 onal structure. In contrast to similar superselective binding previously o
 bserved at surfaces\, we have identified that a key effect in a three-dime
 nsional environment is that the presence of inert crowding agents can sign
 ificantly enhance or even introduce superselectivity [1]. Second\, during 
 seed development of the plant Arabidopsis thaliana\, micrometer-sized liqu
 id droplets form within the vacuolar lumen and wet the tonoplast. Distinct
  tonoplast shapes arise in response to membrane wetting by droplets and I 
 will discuss a simple theoretical model that conceptualises and rationalis
 es these geometries [2]. Conditions of low membrane spontaneous curvature 
 and moderate wettability favor droplet-induced membrane budding\, whereas 
 high membrane spontaneous curvature and strong wettability promote a membr
 ane nanotube network that forms exclusively at the droplet surface. Finall
 y\, if there is time\, I will discuss an approach based on flicker spectro
 scopy to measure the surface tension of condensates in live cells and appl
 y it to stress granules induced by different chemicals [3]. \n\nReferences
 : [1]. A. R. Christy\, H. Kusumaatmaja and M. A. Miller\, PRL 126\, 028002
  (2021)\; [2] H. Kusumaatmaja et al.\, PNAS 118\, e2024109118 (2021)\; [3]
  J. O. Law\, C. M. Jones\, H. Kusumaatmaja and S. N. Grellscheid\, in prep
 aration (2022).\n
LOCATION:Dept of Chemistry\, Wolfson Lecture Theatre and Zoom
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