Cell size scaling laws: a unified theory

Rollin, Romain; Joanny, Jean‐François; Sens, Pierre

doi:10.1101/2022.08.01.502021

Cited by 8 publications

(10 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mass density of protein and lipid in various compartments changes very little with cell size in proliferating cells ( Figures 2 , 3 ), suggesting that total metabolites are generally proportional to cell dry mass during cell growth ( Rollin, Joanny and Sens, 2022 ). However, this proportionality may not hold when protein synthesis, protein degradation, or global regulators of growth and degradation like mTOR activity are administered.…”

Section: Resultsmentioning

confidence: 99%

The uniformity and stability of cellular mass density in mammalian cell culture

Liu

Kirschner

2022

Front. Cell Dev. Biol.

View full text Add to dashboard Cite

Cell dry mass is principally determined by the sum of biosynthesis and degradation. Measurable change in dry mass occurs on a time scale of hours. By contrast, cell volume can change in minutes by altering the osmotic conditions. How changes in dry mass and volume are coupled is a fundamental question in cell size control. If cell volume were proportional to cell dry mass during growth, the cell would always maintain the same cellular mass density, defined as cell dry mass dividing by cell volume. The accuracy and stability against perturbation of this proportionality has never been stringently tested. Normalized Raman Imaging (NoRI), can measure both protein and lipid dry mass density directly. Using this new technique, we have been able to investigate the stability of mass density in response to pharmaceutical and physiological perturbations in three cultured mammalian cell lines. We find a remarkably narrow mass density distribution within cells, that is, significantly tighter than the variability of mass or volume distribution. The measured mass density is independent of the cell cycle. We find that mass density can be modulated directly by extracellular osmolytes or by disruptions of the cytoskeleton. Yet, mass density is surprisingly resistant to pharmacological perturbations of protein synthesis or protein degradation, suggesting there must be some form of feedback control to maintain the homeostasis of mass density when mass is altered. By contrast, physiological perturbations such as starvation or senescence induce significant shifts in mass density. We have begun to shed light on how and why cell mass density remains fixed against some perturbations and yet is sensitive during transitions in physiological state.

show abstract

Section: Resultsmentioning

confidence: 99%

The uniformity and stability of cellular mass density in mammalian cell culture

Liu

Kirschner

2022

Front. Cell Dev. Biol.

View full text Add to dashboard Cite

show abstract

“…Such cell treatments may also modify the activity of different ion pumps and the composition of trapped osmolytes, including the ratio V m /V d . For example, the same mass of trapped molecules (e.g., amino acids) with the same value of V d can either be bound in large macromolecules or be mobile (larger contribution to N ) [27]. This implies that the value of V m /V d may change due to cell starvation and synchronization that alter protein synthesis rates.…”

Section: Discussionmentioning

confidence: 99%

Volume regulation in adhered cells: roles of surface tension and cell swelling

Adar

Vishen

Joanny

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

The volume of adhered cells has been shown experimentally to decrease during spreading. This effect can be understood from the pump-leak model, which we have extended to include mechano-sensitive ion transporters. We identify a novel effect that has important consequences on cellular volume loss; cells that are swollen due to a modulation of ion transport rates are more susceptible to volume loss in response to a tension increase. This effect explains in a plausible manner the discrepancies between three recent, independent experiments on adhered cells, between which both the magnitude of the volume change and its dynamics varied substantially. We suggest that starved and synchronized cells in two of the experiments were in a swollen state and, consequently, exhibited a large volume loss at steady state. Non-swollen cells, for which there is a very small steady-state volume decrease, are still predicted to transiently lose volume during spreading due to a relaxing viscoelastic tension that is large compared with the steady-state tension. We elucidate the roles of cell swelling and surface tension in cellular volume regulation and discuss their possible microscopic origins.

show abstract

“…We estimate the cell volume V ( t ) as proportional to the sum of all proteins, namely - V ( t ) = α ∑ P i ( t ), having α as the mean volume a single protein occupies [1–4]. This leads to: …”

Section: Supplementary Notesmentioning

confidence: 99%

“…We can now write the rate equations for both the ribosome number and the volume: where we assumed that the degraded ribosomes do not decrease the cell volume, as their components remain part of the cell dry mass [4]. Following the same steps as done previously (Supplementary Note 1.3), one can get an expression for the ribosome concentration: where we defined , which represents the low steady-state ribosome concentration in long times (relative to r 0 ).…”

Section: Supplementary Notesmentioning

confidence: 99%

Physiological stress drives the emergence of aSalmonellasubpopulation through ribosomal RNA regulation

Mattioli

Eisner

Rosenbaum

et al. 2023

Preprint

View full text Add to dashboard Cite

Bacteria undergo cycles of growth and starvation, to which they must adapt swiftly. One important strategy for adjusting growth rates relies on ribosomal levels. While high ribosomal levels are required for fast growth, their dynamics during starvation remain unclear. Here, we analyzed ribosomal RNA (rRNA) content of individualSalmonellacells using Fluorescence In-Situ Hybridization (rRNA-FISH). During the transition from exponential to stationary phase we measured a dramatic decrease in rRNA numbers only in a subpopulation, resulting in a bimodal distribution of cells with high and low rRNA content. We showed that the two subpopulations are phenotypically distinct when subjected to nutritional upshifts. Using a transposon screen coupled with rRNA-FISH, we identified two mutants acting on rRNA transcription shutdown and degradation, that abolished the formation of the subpopulation with low rRNA content. Our work suggests thatSalmonellaemploys a bet-hedging strategy in regulating ribosomal levels that may be beneficial for survival.

show abstract

Cell size scaling laws: a unified theory

Cited by 8 publications

References 56 publications

The uniformity and stability of cellular mass density in mammalian cell culture

The uniformity and stability of cellular mass density in mammalian cell culture

Volume regulation in adhered cells: roles of surface tension and cell swelling

Physiological stress drives the emergence of aSalmonellasubpopulation through ribosomal RNA regulation

Contact Info

Product

Resources

About