scholarly journals Heterogeneity of clonal lymphocytes with regard to bcl-2 protein concentration and cell size.

1997 ◽  
Vol 50 (6) ◽  
pp. 326-328
Author(s):  
T J Bromidge ◽  
D J Howe ◽  
S A Johnson ◽  
S A Rule
Keyword(s):  
Cell Size ◽  
Protein Concentration

scholarly journals Increasing cell size remodels the proteome and promotes senescence

2021 ◽  
Author(s):  
Michael C Lanz ◽  
Evgeny Zatulovskiy ◽  
Matthew P Swaffer ◽  
Lichao Zhang ◽  
Shuyuan Zhang ◽  
...  
Keyword(s):  
Cell Size ◽  
Protein Concentration ◽  
Cell Function ◽  
Size Control ◽  
Cell Physiology ◽  
Proliferating Cells ◽  
Size Dependent ◽  
Large Size ◽  
Concentration Changes ◽  
Proteome Changes

Cell size is tightly controlled in healthy tissues, but it is poorly understood how cell size affects cell physiology. To address this, we measured how the proteome changes with cell size. Protein concentration changes are widespread, depend on the DNA-to-cell size ratio, and are predicted by subcellular localization, size-dependent mRNA concentrations, and protein turnover. As proliferating cells grow larger, concentration changes associated with cellular senescence are increasingly pronounced, suggesting that large size may be a cause rather than just a consequence of cell senescence. Consistent with this hypothesis, larger cells are prone to replicative-, DNA damage-, and CDK4/6i-induced senescence. More broadly, our findings show how cell size could impact many aspects of cell physiology through remodeling the proteome, thereby providing a rationale for cell size control to optimize cell function.

scholarly journals Multi-phosphorylation reaction and clustering tune Pom1 gradient mid-cell levels according to cell size

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Veneta Gerganova ◽  
Charlotte Floderer ◽  
Anna Archetti ◽  
Laetitia Michon ◽  
Lina Carlini ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cell Size ◽  
Protein Concentration ◽  
Single Cells ◽  
Lateral Diffusion ◽  
Membrane Association ◽  
Allelic Series ◽  
Concentration Gradients ◽  
Mitotic Entry ◽  
Phosphorylation Reaction

Protein concentration gradients pattern developing organisms and single cells. In Schizosaccharomyces pombe rod-shaped cells, Pom1 kinase forms gradients with maxima at cell poles. Pom1 controls the timing of mitotic entry by inhibiting Cdr2, which forms stable membrane-associated nodes at mid-cell. Pom1 gradients rely on membrane association regulated by a phosphorylation-dephosphorylation cycle and lateral diffusion modulated by clustering. Using quantitative PALM imaging, we find individual Pom1 molecules bind the membrane too transiently to diffuse from pole to mid-cell. Instead, we propose they exchange within longer lived clusters forming the functional gradient unit. An allelic series blocking auto-phosphorylation shows that multi-phosphorylation shapes and buffers the gradient to control mid-cell levels, which represent the critical Cdr2-regulating pool. TIRF imaging of this cortical pool demonstrates more Pom1 overlaps with Cdr2 in short than long cells, consistent with Pom1 inhibition of Cdr2 decreasing with cell growth. Thus, the gradients modulate Pom1 mid-cell levels according to cell size.

Correlation between protein concentration and bacterial cell size can reveal mechanisms of gene expression

2020 ◽  
Vol 17 (4) ◽  
pp. 045002 ◽  
Author(s):  
César Nieto-Acuña ◽  
Juan Carlos Arias-Castro ◽  
César Vargas-García ◽  
Carlos Sánchez ◽  
Juan Manuel Pedraza
Keyword(s):  
Gene Expression ◽  
Cell Size ◽  
Bacterial Cell ◽  
Protein Concentration

scholarly journals Multi-phosphorylation reaction and clustering tune Pom1 gradient mid-cell levels according to cell size

2019 ◽  
Author(s):  
Veneta Gerganova ◽  
Charlotte Floderer ◽  
Anna Archetti ◽  
Laetitia Michon ◽  
Lina Carlini ◽  
...  
Keyword(s):  
Cell Size ◽  
Protein Concentration ◽  
Single Cells ◽  
Quantitative Imaging ◽  
Lateral Diffusion ◽  
Single Particle Tracking ◽  
Allelic Series ◽  
Concentration Gradients ◽  
Tirf Microscopy ◽  
Phosphorylation Reaction

AbstractProtein concentration gradients convey information at a distance from the source to both pattern developing organisms and organize single cells. In the rod-shaped cells of Schizosaccharomyces pombe, the DYRK-family kinase Pom1 forms concentration gradients with maxima at the cell poles. Pom1 controls the timing of mitotic entry by inhibiting the SAD-family kinase Cdr2, which forms stable membrane-associated nodes at mid-cell. Pom1 gradients rely on membrane association regulated by a phosphorylation-dephosphorylation cycle and lateral diffusion modulated by clustering. Whether the graded pattern directly alters Pom1 medial levels has been controversial. Here, using a combination of quantitative imaging approaches, including single particle tracking PALM and TIRF microscopy, we find that individual Pom1 molecules do not bind the membrane long enough to diffuse from cell pole to cell middle. Instead we propose they exchange within longer-lived clusters that form the functional gradient units. By creating an allelic series progressively blocking auto-phosphorylation, we show that multi-phosphorylation shapes and buffers the gradient to control the cortical mid-cell Pom1 levels, which represent the critical pool regulating Cdr2. Specific imaging of this cortical pool by TIRF microscopy demonstrates that more Pom1 overlaps with Cdr2 nodes in short than long cells, consistent with Pom1 inhibition of Cdr2 decreasing with cell growth. We conclude that Pom1 gradients modulate Pom1 mid-cell levels according to cell size.

scholarly journals Stochasticity in bacterial division control: Preliminary consequences for protein concentration

2019 ◽  
Author(s):  
Cesar Augusto Nieto Acuna ◽  
Cesar Augusto Vargas Garcia ◽  
Juan Manuel Pedraza
Keyword(s):  
Chromosome Number ◽  
Cell Size ◽  
Protein Concentration ◽  
Occurrence Rate ◽  
Mrna Synthesis ◽  
Bacterial Division ◽  
Cellular Volume ◽  
Constant Rate ◽  
Classical Models ◽  
Protein Number

ABSTRACTThe stochastic nature of protein concentration inside cells can have important consequences in their physiology and population fitness. Classical models of gene expression consider these processes as first-order reactions with little dependence with the cell size. However, the concentrations of the relevant molecules depend directly on the cellular volume. Here we model the cell size dynamics as exponential growth followed by division with occurrence rate proportional to the size. This framework, together with known models of chromosome replication and both protein and mRNA synthesis, lets us predict relationships between cell size and both protein number and concentration. As a main result, we find that protein production strategies (constant rate or rate proportional to either chromosome number, cell size or chromosome number times cell size) can be experimentally distinguished from the correlation between protein concentration and cell size.

Albumin-Induced Endocytic Vacuoles in Tetrahymena Pyrijormis

1975 ◽  
Vol 33 ◽  
pp. 694-695
Author(s):  
L. J. Brenner ◽  
D. G. Osborne ◽  
B. L. Schumaker
Keyword(s):  
Electron Microscopy ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Protein Concentration ◽  
Tetrahymena Pyriformis ◽  
Sequence Of Events ◽  
Cytoplasmic Bodies ◽  
Food Vacuoles ◽  
Mouse Ascites ◽  
Normal Human

Exposure of the ciliate, Tetrahymena pyriformis, strain WH6, to normal human or rabbit sera or mouse ascites fluids induces the formation of large cytoplasmic bodies. By electron microscopy these (LB) are observed to be membrane-bounded structures, generally spherical and varying in size (Fig. 1), which do not resemble the food vacuoles of cells grown in proteinaceous broth. The possibility exists that the large bodies represent endocytic vacuoles containing material concentrated from the highly nutritive proteins and lipoproteins of the sera or ascites fluids. Tetrahymena mixed with bovine serum albumin or ovalbumin solutions having about the same protein concentration (7g/100 ml) as serum form endocytic vacuoles which bear little resemblance to the serum-induced LB. The albumin-induced structures (Fig. 2) are irregular in shape, rarely spherical, and have contents which vary in density and consistency. In this paper an attempt is made to formulate the sequence of events which might occur in the formation of the albumin-induced vacuoles.

Spindle scaling mechanisms

2020 ◽  
Vol 64 (2) ◽  
pp. 383-396
Author(s):  
Lara K. Krüger ◽  
Phong T. Tran
Keyword(s):  
Cell Size ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Size Dependent ◽  
A Cell ◽  
Chromosome Separation ◽  
Spindle Elongation ◽  
Protein Gradients ◽  
Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

Monoamine Oxidase and Other Mitochondrial Enzymes in Density Subpopulations of Human Platelets

1988 ◽  
Vol 59 (01) ◽  
pp. 029-033 ◽  
Author(s):  
K G Chamberlain ◽  
D G Penington
Keyword(s):  
Monoamine Oxidase ◽  
Protein Concentration ◽  
Close Correlation ◽  
Human Platelets ◽  
Mitochondrial Enzymes ◽  
Density Fractions ◽  
Percoll Gradients ◽  
Normal Human ◽  
The Mean ◽  
Very High

SummaryNormal human platelets have been separated according to density on continuous Percoll gradients and the platelet distribution divided into five fractions containing approximately equal numbers of platelets. The mean volumes and protein contents of the platelets in each fraction were found to correlate positively with density while the protein concentration did not differ significantly between the fractions. Four mitochondrial enzymes (monoamine oxidase, glutamate dehydrogenase, cytochrome oxidase and NADP-dependent isocitrate dehydrogenase) were assayed and their activities per unit volume were found to increase in a very similar monotonie fashion with platelet density. When MAO and GDH were assayed on the same set of density fractions the correlation between the two activities was very high (r = 0.94–1.00, p <0.001) and a similar close correlation was found between MAO and ICDH. The results support the hypothesis that high density platelets either have a higher concentration of mitochondria or have larger mitochondria than low density platelets.

Does Low Protein Concentration of Tissue-type Plasminogen Activator Predict a Low Risk of Spontaneous Deep Vein Thrombosis?

1995 ◽  
Vol 74 (02) ◽  
pp. 718-721 ◽  
Author(s):  
Jørgen Gram ◽  
Johannes Sidelmann ◽  
Jørgen Jespersen
Keyword(s):  
Deep Vein Thrombosis ◽  
Confidence Interval ◽  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Protein Concentration ◽  
Tissue Type ◽  
Vein Thrombosis ◽  
Low Protein ◽  
Deep Vein ◽  
Pai 1

SummaryMany reports have demonstrated an abnormal fibrinolysis in a subset of patients with deep vein thrombosis. We have studied systemic global fibrinolytic activity and protein concentrations of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) in plasma of 25 young patients with a previous instance of spontaneous deep vein thrombosis documented by phlebography and in 50 healthy controls. The two populations were comparable with respect to a number of base-line variables (age, height, weight, etc.), while the patients had significantly lower fibrinolytic activity (p <0.02), and significantly higher protein concentrations of t-PA (p <0.0001) and PAI-1 (p <0.0006).We used probit scale plots to identify the consequence of different cut-off points to separate patients from controls. Reasonable separation could be obtained for t-PA with a cut-off point of 5.2 ng/ml and for PAI-1 18 ng/ml. The sensitivity and specificity for these cut-off points were for t-PA 73% (95% confidence interval 63%-84%) and for PAI-1 67% (confidence interval 55%-77%). The negative predictive value with a cut-off point t-PA concentration of 5.2 ng/ml was 85% (95% confidence interval 70%-94%). We observed a significantly negative association between concentration of t-PA and fibrinolytic activity (rs = -0.47; p <0.005) and also between PAI-1 and fibrinolytic activity (rs = -0.78; p <0.005).We conclude that a young healthy population is characterized by low protein concentration of t-PA (and PAI-1) compared with young patients with a previous instance of spontaneous vein thrombosis, and we tentatively state that a low protein concentration of t-PA predicts a low risk of spontaneous deep vein thrombosis.

Shifts in cell size and community composition of bacterioplankton due to grazing by heterotrophic flagellates: evidence from a marine system

2019 ◽  
Vol 83 (3) ◽  
pp. 295-308
Author(s):  
MG Weinbauer ◽  
S Suominen ◽  
J Jezbera ◽  
ME Kerros ◽  
S Marro ◽  
...  
Keyword(s):  
Cell Size ◽  
Community Composition ◽  
Heterotrophic Flagellates ◽  
Marine System
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