
@article {115040,
	title = {Active emulsions in living cell membranes driven by contractile stresses and transbilayer coupling},
	journal = {Proc Natl Acad Sci U S A.},
	volume = {119},
	year = {2022},
	month = {07/2022},
	pages = {e2123056119},
	abstract = {<p>The spatiotemporal organization of proteins and lipids on the cell surface has direct functional consequences for signaling, sorting, and endocytosis. Earlier studies have shown that multiple types of membrane proteins, including transmembrane proteins that have cytoplasmic actin binding capacity and lipid-tethered glycosylphosphatidylinositol-anchored proteins (GPI-APs), form nanoscale clusters driven by active contractile flows generated by the actin cortex. To gain insight into the role of lipids in organizing membrane domains in living cells, we study the molecular interactions that promote the actively generated nanoclusters of GPI-APs and transmembrane proteins. This motivates a theoretical description, wherein a combination of active contractile stresses and transbilayer coupling drives the creation of active emulsions, mesoscale liquid order (lo) domains of the GPI-APs and lipids, at temperatures greater than equilibrium lipid phase segregation. To test these ideas, we use spatial imaging of molecular clustering combined with local membrane order, and we demonstrate that mesoscopic domains enriched in nanoclusters of GPI-APs are maintained by cortical actin activity and transbilayer interactions and exhibit significant lipid order, consistent with predictions of the active composite model.</p>
},
	doi = {10.1073/pnas.2123056119},
	author = {Saha, Suvrajit and Das, A and Patra, C and Anilkumar, AA and Sil, Parijat and Mayor, Satyajit and Rao, Madan}
}
@article {78170,
	title = {Stratification relieves constraints from steric hindrance in the generation of compact actomyosin asters at the membrane cortex.},
	journal = {Sci Adv},
	volume = {6},
	year = {2020},
	month = {03/2020},
	abstract = {<p>Recent in vivo studies reveal that several membrane proteins are driven to form nanoclusters by active contractile flows arising from localized dynamic patterning of F-actin and myosin at the cortex. Since myosin-II assemble as minifilaments with tens of myosin heads, one might worry that steric considerations would obstruct the emergence of nanoclustering. Using coarse-grained, agent-based simulations that account for steric constraints, we find that the patterns exhibited by actomyosin in two dimensions, do not resemble the steady-state patterns in our in vitro reconstitution of actomyosin on a supported bilayer. We perform simulations in a thin rectangular slab, separating the layer of actin filaments from myosin-II minifilaments. This recapitulates the observed features of in vitro patterning. Using super resolution microscopy, we find evidence for such stratification in our in vitro system. Our study suggests that molecular stratification may be an important organizing feature of the cortical cytoskeleton in vivo.</p>
},
	doi = {10.1126/sciadv.aay6093},
	author = {Das, A and Bhat, A and Sknepnek, R and K{\"o}ster, D and Mayor, S and Rao, M}
}
