scholarly journals The Ceramide Synthase Subunit Lac1 Regulates Cell Growth and Size in Fission Yeast

2021 ◽  
Vol 23 (1) ◽  
pp. 303
Author(s):  
Ignacio Flor-Parra ◽  
Susana Sabido-Bozo ◽  
Atsuko Ikeda ◽  
Kazuki Hanaoka ◽  
Auxiliadora Aguilera-Romero ◽  
...  
Keyword(s):  
Growth Rate ◽  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Cell Growth ◽  
Fission Yeast ◽  
Lipid Analysis ◽  
Growth Control ◽  
Ceramide Synthase ◽  
Viable Cells ◽  
Complex Sphingolipids

Cell division produces two viable cells of a defined size. Thus, all cells require mechanisms to measure growth and trigger cell division when sufficient growth has occurred. Previous data suggest a model in which growth rate and cell size are mechanistically linked by ceramide-dependent signals in budding yeast. However, the conservation of mechanisms that govern growth control is poorly understood. In fission yeast, ceramide synthase is encoded by two genes, Lac1 and Lag1. Here, we characterize them by using a combination of genetics, microscopy, and lipid analysis. We showed that Lac1 and Lag1 co-immunoprecipitate and co-localize at the endoplasmic reticulum. However, each protein generates different species of ceramides and complex sphingolipids. We further discovered that Lac1, but not Lag1, is specifically required for proper control of cell growth and size in Schizosaccharomyces pombe. We propose that specific ceramide and sphingolipid species produced by Lac1 are required for normal control of cell growth and size in fission yeast.

scholarly journals A conserved cell growth cycle can account for the environmental stress responses of divergent eukaryotes

2012 ◽  
Vol 23 (10) ◽  
pp. 1986-1997 ◽  
Author(s):  
Nikolai Slavov ◽  
Edoardo M. Airoldi ◽  
Alexander van Oudenaarden ◽  
David Botstein
Keyword(s):  
Gene Expression ◽  
Growth Rate ◽  
Oxygen Consumption ◽  
Heat Stress ◽  
Cell Division ◽  
Environmental Stress ◽  
Fission Yeast ◽  
Budding Yeast ◽  
Cell Division Cycle ◽  
Metabolic Cycle

The respiratory metabolic cycle in budding yeast (Saccharomyces cerevisiae) consists of two phases that are most simply defined phenomenologically: low oxygen consumption (LOC) and high oxygen consumption (HOC). Each phase is associated with the periodic expression of thousands of genes, producing oscillating patterns of gene expression found in synchronized cultures and in single cells of slowly growing unsynchronized cultures. Systematic variation in the durations of the HOC and LOC phases can account quantitatively for well-studied transcriptional responses to growth rate differences. Here we show that a similar mechanism—transitions from the HOC phase to the LOC phase—can account for much of the common environmental stress response (ESR) and for the cross-protection by a preliminary heat stress (or slow growth rate) to subsequent lethal heat stress. Similar to the budding yeast metabolic cycle, we suggest that a metabolic cycle, coupled in a similar way to the ESR, in the distantly related fission yeast, Schizosaccharomyces pombe, and in humans can explain gene expression and respiratory patterns observed in these eukaryotes. Although metabolic cycling is associated with the G0/G1 phase of the cell division cycle of slowly growing budding yeast, transcriptional cycling was detected in the G2 phase of the division cycle in fission yeast, consistent with the idea that respiratory metabolic cycling occurs during the phases of the cell division cycle associated with mass accumulation in these divergent eukaryotes.

Surface T-antigen expression in simian virus 40-transformed mouse cells: correlation with cell growth rate

1985 ◽  
Vol 5 (5) ◽  
pp. 1051-1057
Author(s):  
M Santos ◽  
J S Butel
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Growth Control ◽  
Simian Virus 40 ◽  
Antigen Expression ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Seeding Density ◽  
Cell Growth Rate

Cell growth control appears to be drastically altered as a consequence of transformation. Because the cell surface appears to have a role in modulating cell growth and simian virus 40 (SV40)-transformed cells express large T antigen (T-Ag) in the plasma membrane, we investigated whether surface T-Ag expression varies according to cell growth rate. Different growth states were obtained by various combinations of seeding density, serum concentration, and temperature, and cell cycle distributions were determined by flow microcytofluorometry. Actively dividing SV40-transformed mouse cell cultures were consistently found to express higher levels of surface T-Ag and T-Ag/p53 complex than cultures in which cells were mostly resting. In addition, the T-Ag/p53 complex disappeared from the surface of tsA7-transformed cells cultured under restrictive conditions known to induce complete growth arrest (39.5 degrees C), although the surface complex did not disappear from other tsA transformants able to keep cycling at 39.5 degrees C. These results suggest that surface SV40 T-Ag or surface T-Ag/p53 complex, or both, are involved in determining the growth characteristics of SV40-transformed cells.

scholarly journals Ca2+Pools and Cell Growth

2001 ◽  
Vol 276 (50) ◽  
pp. 47608-47614 ◽  
Author(s):  
Guillaume Legrand ◽  
Sandrine Humez ◽  
Christian Slomianny ◽  
Etienne Dewailly ◽  
Fabien Vanden Abeele ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Growth Rate ◽  
Endoplasmic Reticulum ◽  
Growth Factor ◽  
Cell Growth ◽  
Intracellular Calcium ◽  
Lncap Cell ◽  
Fura 2 ◽  
Endoplasmic Reticulum Calcium ◽  
Calcium Pool

The present study demonstrates for the first time that intracellular calcium-ATPases and calcium pool content are closely associated with prostate cancer LNCaP cell growth. Cell growth was modulated by changing the amount of epidermal growth factor, serum, and androgene in culture media. Using the microspectrofluorimetric method with Fura-2 and Mag Fura-2 as probes, we show that in these cells, the growth rate is correlated with intracellular calcium pool content. Indeed, an increased growth rate is correlated with an increase in the calcium pool filling state, whereas growth-inhibited cells show a reduced calcium pool load. Using Western blotting and immunocytochemistry, we show that endoplasmic reticulum calcium pump expression is closely linked to LNCaP cell growth, and are a common target of physiological stimuli that control cell growth. Moreover, we clearly demonstrate that inhibition of these pumps, using thapsigargin, inhibits LNCaP cell growth and prevents growth factor from stimulating cell proliferation. Our results thus provide evidence for the essential role of functional endoplasmic reticulum calcium pumps and calcium pool in control of prostate cancer LNCaP cell growth, raising the prospect of new targets for the treatment of prostate cancer.

scholarly journals Size control in mammalian cells involves modulation of both growth rate and cell cycle duration

2017 ◽  
Author(s):  
Clotilde Cadart ◽  
Sylvain Monnier ◽  
Jacopo Grilli ◽  
Rafaele Attia ◽  
Emmanuel Terriac ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Cell Division ◽  
Cell Growth ◽  
Single Cell ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Size Control ◽  
Cycle Duration ◽  
Mathematical Framework

SummaryDespite decades of research, it remains unclear how mammalian cell growth varies with cell size and across the cell division cycle to maintain size control. Answers have been limited by the difficulty of directly measuring growth at the single cell level. Here we report direct measurement of single cell volumes over complete cell division cycles. The volume added across the cell cycle was independent of cell birth size, a size homeostasis behavior called “adder”. Single-cell growth curves revealed that the homeostatic behavior relied on adaptation of G1 duration as well as growth rate modulations. We developed a general mathematical framework that characterizes size homeostasis behaviors. Applying it on datasets ranging from bacteria to mammalian cells revealed that a near-adder is the most common type of size control, but only mammalian cells achieve it using modulation of both cell growth rate and cell-cycle progression.

scholarly journals Cell growth–dependent coordination of lipid signaling and glycosylation is mediated by interactions between Sac1p and Dpm1p

2005 ◽  
Vol 168 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Frank Faulhammer ◽  
Gerlinde Konrad ◽  
Ben Brankatschk ◽  
Sabina Tahirovic ◽  
Andreas Knödler ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Cell Growth ◽  
Growth Conditions ◽  
Membrane Lipid ◽  
Lipid Phosphatase ◽  
Golgi Membranes ◽  
Er Targeting ◽  
Phosphatidylinositol 4 ◽  
Secretory Capacity

The integral membrane lipid phosphatase Sac1p regulates local pools of phosphatidylinositol-4-phosphate (PtdIns(4)P) at endoplasmic reticulum (ER) and Golgi membranes. PtdIns(4)P is important for Golgi trafficking, yet the significance of PtdIns(4)P for ER function is unknown. It also remains unknown how localization of Sac1p to distinct organellar membranes is mediated. Here, we show that a COOH-terminal region in yeast Sac1p is crucial for ER targeting by directly interacting with dolicholphosphate mannose synthase Dpm1p. The interaction with Dpm1p persists during exponential cell division but is rapidly abolished when cell growth slows because of nutrient limitation, causing translocation of Sac1p to Golgi membranes. Cell growth–dependent shuttling of Sac1p between the ER and the Golgi is important for reciprocal control of PtdIns(4)P levels at these organelles. The fraction of Sac1p resident at the ER is also required for efficient dolichol oligosaccharide biosynthesis. Thus, the lipid phosphatase Sac1p may be a key regulator, coordinating the secretory capacity of ER and Golgi membranes in response to growth conditions.

5-Carboxyfluorescein Diacetate as a Probe for Measuring the Growth of Keratinocytes

1994 ◽  
Vol 13 (6) ◽  
pp. 423-427 ◽  
Author(s):  
M. Hanthamrongwit ◽  
W.H. Reid ◽  
J.M. Courtney ◽  
M.H. Grant
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Convenient Method ◽  
Mouse Fibroblast ◽  
Cell Counting ◽  
Cell Protein ◽  
Seeding Density ◽  
Collagen Gels ◽  
Viable Cells

There is a requirement for a convenient and reliable method for evaluating the growth rate of human keratinocytes cultured on collagen-based substrates. Therefore, three methods of determining cell growth were first used to quantify the growth rate of the well-characterised L929 mouse fibroblast cell line on tissue culture plastic and the results compared. The methods used were the measurement of total cell protein, cell counting using an electronic Coulter counter and a fluorimetric assay employing 5-carboxyfluorescein diacetate (CFDA). The CFDA assay showed the highest correlation with seeding density of the L929 cells, and the lowest standard deviations. It was the most rapid and convenient method for processing large numbers of samples. Only viable cells can deacetylate the non-fluorescent CFDA to carboxyfluorescein, which is fluorescent and accumulates inside the cells. Therefore, the assay specifically quantifies only viable cells. Subsequently, this assay has been successfully applied to the measurement of human keratinocyte growth rate on collagen gels and sponges. We have demonstrated that keratinocytes grow equally well on gels and sponges, and that media containing low calcium concentrations (0.09 mM) favour rapid proliferation of keratinocytes. Our results show that the CFDA assay is an accurate, reliable and convenient method for quantifying cell growth in vitro. It is particularly valuable when growing cells on optically opaque substrata, such as collagen sponges, where growth cannot be monitored daily by microscopy.

scholarly journals Surface T-antigen expression in simian virus 40-transformed mouse cells: correlation with cell growth rate.

1985 ◽  
Vol 5 (5) ◽  
pp. 1051-1057 ◽  
Author(s):  
M Santos ◽  
J S Butel
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Growth Control ◽  
Simian Virus 40 ◽  
Antigen Expression ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Seeding Density ◽  
Cell Growth Rate

Cell growth control appears to be drastically altered as a consequence of transformation. Because the cell surface appears to have a role in modulating cell growth and simian virus 40 (SV40)-transformed cells express large T antigen (T-Ag) in the plasma membrane, we investigated whether surface T-Ag expression varies according to cell growth rate. Different growth states were obtained by various combinations of seeding density, serum concentration, and temperature, and cell cycle distributions were determined by flow microcytofluorometry. Actively dividing SV40-transformed mouse cell cultures were consistently found to express higher levels of surface T-Ag and T-Ag/p53 complex than cultures in which cells were mostly resting. In addition, the T-Ag/p53 complex disappeared from the surface of tsA7-transformed cells cultured under restrictive conditions known to induce complete growth arrest (39.5 degrees C), although the surface complex did not disappear from other tsA transformants able to keep cycling at 39.5 degrees C. These results suggest that surface SV40 T-Ag or surface T-Ag/p53 complex, or both, are involved in determining the growth characteristics of SV40-transformed cells.

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