Robustness and Universality in Organelle Size Control

Limiting Pool and Actin Architecture Controls Myosin Cluster Sizes in Adherent Cells

“…Our understanding of myosin cluster regulation is consistent with the idea that the number and size of subcellular organelles are tightly controlled (Marshall, 2016;Chen and Levy, 2022;Amiri et al, 2023). One model of organelle size control is that a limited pool of cytoplasmic components sets the size of these structures.…”

Liquid structure of bistable responsive macromolecules using mean-field density-functional theory

“…Applying this functional differentiation to eqn (10) and using eqn (9) leads to the so-called Euler-Lagrange equation k B T ln(r(r,s)L 3 /p 0 ) + u ext (r,s) + c(s) + m ex (r,s) À m 0 = 0 (12) where the excess chemical potential m ex (r,s) is obtained from the functional differentiation of the excess free energy m ex ðr; sÞ dF ex drðr; sÞ…”

“…Solving eqn (12) for the particle density r(r,s), we find rðr; sÞ ¼ e bm 0 p 0 L 3 exp ÀbcðsÞ À bu ext ðr; sÞ À bm ex ðr;…”

“…However, due their polymeric nature the particles feature large conformational behavior and rather behave in many cases effectively as soft and responsive, and so are able to modify their effective size in response to the external stimuli. For instance, organelle sizes inside the cell fluctuate in demand, swelling or shrinking, to preserve the cell homeostasis, 12 and soft and compressible lipid vesicles undergo compaction by increasing the concentration of high molecular weight PEG-based crowders. 13 Furthermore, the conformation of biological or functional macromolecules often displays a two-state behavior, such as in folded/unfolded or globule/coil transitions of proteins and polymers.…”

Organelle Building Codes

“…iologists have identified within cells many specialized structures called organelles that carry out crucial tasks, but how cells regulate the size and the number of organelles has remained a puzzle. Now, using simulations backed by experiments, biophysicists have demonstrated that cells appear to produce organelles through a seemingly erratic, or "bursty," growth process, which enables them to control average organelle sizes and numbers while also constraining organelle size variations within any cell [1]. The work helps to build up a more fundamental understanding of the mechanisms of cellular function.…”