Transcription by RNA polymerases I and III: a potential link between cell growth, protein synthesis and the retinoblastoma protein

1998 ◽  
Vol 76 (2) ◽  
pp. 94-103 ◽  
Author(s):  
Christopher G. C. Larminie ◽  
Hadi M. Alzuherri ◽  
Carol A. Cairns ◽  
Angela McLees ◽  
R. J. White
Keyword(s):  
Protein Synthesis ◽  
Cell Growth ◽  
Retinoblastoma Protein ◽  
Rna Polymerases ◽  
Potential Link

mTORC1 regulates the efficiency and cellular capacity for protein synthesis

2013 ◽  
Vol 41 (4) ◽  
pp. 923-926 ◽  
Author(s):  
Christopher G. Proud
Keyword(s):  
Protein Synthesis ◽  
Growth Factors ◽  
Cell Growth ◽  
Translation Initiation ◽  
Ribosomal Proteins ◽  
Mammalian Target Of Rapamycin ◽  
Rna Polymerases ◽  
Short Term ◽  
Cellular Capacity ◽  
Cell Growth And Proliferation

mTORC1 (mammalian target of rapamycin complex 1) is activated by nutrients, growth factors and certain hormones. Signalling downstream of mTORC1 promotes protein synthesis by both activating the processes of translation initiation and elongation, in the short term, and the production of new ribosomes, in the longer term. mTORC1 signalling stimulates the translation of the mRNAs encoding the ribosomal proteins, activates RNA polymerases I and III, which make the rRNAs, and promotes the processing of the precursor for the main rRNAs. Taken together, these effects allow mTORC1 signalling to drive cell growth and proliferation.

Ca2+ dynamics of thrombin-stimulated rat heart-derived embryonic myocytes: relationship to protein synthesis and cell growth

2003 ◽  
Vol 35 (11) ◽  
pp. 1573-1587 ◽  
Author(s):  
Margaret A. Brostrom ◽  
Zui Pan ◽  
Sally Meiners ◽  
Christopher Drumm ◽  
Ijaz Ahmed ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Cell Growth ◽  
Rat Heart

CELLULAR GROWTH HORMONES, NUTRITION, AND TIME

PEDIATRICS ◽  
1968 ◽  
Vol 41 (1) ◽  
pp. 30-46
Author(s):  
Donald B. Cheek
Keyword(s):  
Growth Hormone ◽  
Body Composition ◽  
Body Weight ◽  
Protein Synthesis ◽  
Steady State ◽  
Cell Growth ◽  
Cell Mass ◽  
Cell Number ◽  
Fat Cells ◽  
Number Of Cells

For many years the study of growth has rested mainly on the application of anthropometric techniques and the measurement of height and weight. A few years ago Tanner9 correctly pointed out that studies on body composition were mainly related to body weight and, therefore, added little to the thinking. A more penetrating approach to the study of growth was recommended.2 The present approach,11 documented in part here, has been to apply biochemical and physiological techniques for the measurement of body cell mass, cell size, cell number and, to some extent, cell function. Body function and heat production as well as maturational age have been of concern. These studies have been made in the same children at tile same time. It is anticipated that inspection of these three dimensions of growth, size, function, and maturational age should help to elucidate problems related to growth retardation. In the clinic it is possible to predict cell-extracellular mass of children by applying equations based on relationships between body composition and height and weight. We began by presenting information on growth of muscle and the differences between the sexes with the progress of time and with respect to size and number of cells. Increments in growth rate of the male at adolescence were found. Such differences in cell growth must be related to some extent to the restrictive action of estrogens on cell multiplication in the female and to the stimulating action of androgens in the male. Growth hormone is an important hormone for the multiplication of cells, while insulin is of importance to protein synthesis. Both hormones are needed for growth. Thyroid hormone appears to play a secondary role but is important to protein synthesis especially in early postnatal life. The energy requirement for normal growth is only slightly above the basal state and the visceral cell mass is the most direct standard of reference for heat production. Restriction of nutrition can either retard growth in the size of cells, in the number of cells, or both. Current studies58 show that ingestion of protein and calories incite the secretion of growth hormone and insulin in specific patterns and at appropriate times. Growth hormone has been labelled the "feasting" hormone and insulin tile "feasting" hormone.59 Thus, the subtle relationship between nutrition and cell growth becomes apparent. Of concern is the possibility that overnutrition early in life may program excess secretion of hormones such as insulin or growth hormone. Overnutrition is a major problem in the affluent society, while conservative nutrition is compatible with longevity.6 Hirsch, et al.60 informs us that growth of adipose tissue is mainly by cell number increase–as we have seen for muscle. Again, a steady state of cell number is reached for fat cells. But, obese subjects have an excess of fat cells which do not disappear with time and diet. Such cells become increasingly insensitive to insulin as they enlarge.61 One might view the passing parade of life and growth and observe the relation of the intracellular phase to body weight from infancy to senility (Fig. 12). Here we see the upward increase of cell mass with respect to time and body weight increase. The adult data are taken from F. D. Moore.62 Clearly, with senility we can suspect that more and more of the body weight is extracellular or connective tissue and less and less of the weight is soft tissue or oxidizing protoplasm. Data on body potassium are even more remarkable in this demonstration.11 It is difficult to say with Browning: Grow old along with me! The best is yet to be.... Nevertheless, it is possible that with increased information and research the understanding of these stages of cell growth will be achieved and, no doubt, the departure from the steady state of cell population which occurs at the autumn of our existence– when cancer, and cardiovascular disease supervene–will be understood.63 However, the problems of aging can only be exposed after the physiology of growth is understood.

Wachstumsparameter in normalen und durch Actinomycin verlängerten Zellzyklen von Tetrahymena / Growth Parameters in Normal and Actinomycin-induced prolonged Cell Cycles of Tetrahymena

1969 ◽  
Vol 24 (12) ◽  
pp. 1624-1629 ◽  
Author(s):  
Günter Cleffmann
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Growth ◽  
Rna Synthesis ◽  
Growth Parameters ◽  
Average Duration ◽  
Cell Cycles ◽  
Growing Cell

Actinomycin in low concentration (0,2 μg/ml — 0,5 μg/ml) prolongs the average duration of the cell cycle of Tetrahymena considerably, but does not inhibit cell division completely. Some parameters of the growing cell have been tested in cell cycles extended in this way and compared to those of normally growing cells. The RNA synthesis of treated cells is reduced to such an extent that the RNA content per cell decreases during the prolonged cell cycle. Nevertheless cell growth, protein synthesis and DNA replication proceed at almost the same rate as in untreated cells. These findings indicate that the presence of actinomycin does not interfere with RNA fractions necessary for growth but reduce the synthesis of RNA fractions which are essential for cell division. Therefore a longer period is needed for their accumulation.

scholarly journals Interleukin-6 promotes multiple myeloma cell growth via phosphorylation of retinoblastoma protein

Blood ◽  
1996 ◽  
Vol 88 (6) ◽  
pp. 2219-2227 ◽  
Author(s):  
M Urashima ◽  
A Ogata ◽  
D Chauhan ◽  
MB Vidriales ◽  
G Teoh ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
B Cells ◽  
Cell Growth ◽  
Tumor Cell ◽  
Cell Lines ◽  
Interleukin 6 ◽  
Growth Arrest ◽  
Retinoblastoma Protein ◽  
Myeloma Cell ◽  
Phosphorylated Form

Interleukin-6 (IL-6) mediates autocrine and paracrine growth of multiple myeloma (MM) cells and inhibits tumor cell apoptosis. Abnormalities of retinoblastoma protein (pRB) and mutations of RB gene have been reported in up to 70% of MM patients and 80% of MM-derived cell lines. Because dephosphorylated (activated) pRB blocks transition from G1 to S phase of the cell cycle whereas phosphorylated (inactivated) pRB releases this growth arrest, we characterized the role of pRB in IL-6-mediated MM cell growth. Both phosphorylated and dephosphorylated pRB were expressed in all serum-starved MM patient cells and MM-derived cell lines, but pRB was predominantly in its phosphorylated form. In MM cells that proliferated in response to IL-6, exogenous IL-6 downregulated dephosphorylated pRB and decreased dephosphorylated pRB-E2F complexes. Importantly, culture of MM cells with RB antisense, but not RB sense, oligonucleotide (ODN) triggered IL- 6 secretion and proliferation in MM cells; however, proliferation was only partially inhibited by neutralizing anti-IL-6 monoclonal antibody (MoAb). In contrast to MM cells, normal splenic B cells express dephosphorylated pRB. Although CD40 ligand (CD40L) triggers a shift from dephosphorylated to phosphorylated pRB and proliferation of B cells, the addition of exogenous IL-6 to CD40L-treated B cells does not alter either pRB or proliferation, as observed in MM cells. These results suggest that phosphorylated pRB is constitutively expressed in MM cells and that IL-6 further shifts pRB from its dephosphorylated to its phosphorylated form, thereby promoting MM cell growth via two mechanisms; by decreasing the amount of E2F bound by dephosphorylated pRB due to reduced dephosphorylated pRB, thereby releasing growth arrest; and by upregulating IL-6 secretion by MM cells and related IL-6- mediated autocrine tumor cell growth.

scholarly journals ANTAGONISM BY DIBUTYRYL ADENOSINE CYCLIC 3',5'-MONOPHOSPHATE AND TESTOSTERONE OF CELL ROUNDING REACTIONS

1973 ◽  
Vol 59 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Brian Storrie
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Cell Growth ◽  
Concanavalin A ◽  
Divalent Cations ◽  
Cell Growth Rate ◽  
Dibutyryl Camp ◽  
Cell Rounding ◽  
Drug Removal ◽  
Kinetics Of

In an attempt to understand further the mechanism of the morphological and functional "reverse transformation" of CHO-K1 cells induced by dibutyryl adenosine cyclic 3',5'-monophosphate (cAMP) and testosterone, the kinetics of variation in the susceptibility of cells to rounding after the addition or deletion of dibutyryl cAMP and testosterone have been investigated. Changes in susceptibility to cell rounding upon removal of divalent cations or pulse exposure to concanavalin A were complete within 0.5–1 h after addition or deletion of drug. In comparison, the gross conversion of CHO-K1 cells from epithelial- to fibroblast-like morphology after drug treatment or the converse change after drug removal required 8 or 4 h, respectively. The effects on cell rounding are not caused by an effect of dibutyryl cAMP upon cell growth rate. Inhibitor experiments indicate that the changes investigated do not require continued RNA or protein synthesis and are not prevented by agents which depolymerize microtubules.

scholarly journals Keratins and protein synthesis: the plot thickens

2009 ◽  
Vol 187 (2) ◽  
pp. 157-159 ◽  
Author(s):  
Juliane C. Kellner ◽  
Pierre A. Coulombe
Keyword(s):  
Protein Synthesis ◽  
Cell Growth ◽  
Epithelial Cells ◽  
Mechanical Stress ◽  
Gene Cluster ◽  
Organelle Transport ◽  
Type Ii ◽  
Keratin Gene ◽  
Cell Biol ◽  
Keratin Proteins

In addition to protecting epithelial cells from mechanical stress, keratins regulate cytoarchitecture, cell growth, proliferation, apoptosis, and organelle transport. In this issue, Vijayaraj et al. (2009. J. Cell Biol. doi:10.1083/jcb.200906094) expand our understanding of how keratin proteins participate in the regulation of protein synthesis through their analysis of mice lacking the entire type II keratin gene cluster.

scholarly journals Growth Suppression by an E2F-Binding-Defective Retinoblastoma Protein (RB): Contribution from the RB C Pocket

1998 ◽  
Vol 18 (7) ◽  
pp. 4032-4042 ◽  
Author(s):  
Laura L. Whitaker ◽  
Heyun Su ◽  
Rajasekaran Baskaran ◽  
Erik S. Knudsen ◽  
Jean Y. J. Wang
Keyword(s):  
Cell Growth ◽  
Tyrosine Kinase ◽  
Protein Binding ◽  
Growth Arrest ◽  
Retinoblastoma Protein ◽  
Growth Suppression ◽  
Peptide Motif ◽  
Abl Tyrosine Kinase ◽  
Transcription Regulators

ABSTRACT Growth suppression by the retinoblastoma protein (RB) is dependent on its ability to form complexes with transcription regulators. At least three distinct protein-binding activities have been identified in RB: the large A/B pocket binds E2F, the A/B pocket binds the LXCXE peptide motif, and the C pocket binds the nuclear c-Abl tyrosine kinase. Substitution of Trp for Arg 661 in the B region of RB (mutant 661) inactivates both E2F and LXCXE binding. The tumor suppression function of mutant 661 is not abolished, because this allele predisposes its carriers to retinoblastoma development with a low penetrance. In cell-based assays, 661 is shown to inhibit G1/S progression. This low-penetrance mutant also induces terminal growth arrest with reduced but detectable activity. We have constructed mutations that disrupt C pocket activity. When overproduced, the RB C-terminal fragment did not induce terminal growth arrest but could inhibit G1/S progression, and this activity was abolished by the C-pocket mutations. In full-length RB, the C-pocket mutations reduced but did not abolish RB function. Interestingly, combination of the C-pocket and 661 mutations completely abolished RB’s ability to cause an increase in the percentage of cells in G1 and to induce terminal growth arrest. These results suggest that the A/B or C region can induce a prolongation of G1 through mechanisms that are independent of each other. In contrast, long-term growth arrest requires combined activities from both regions of RB. In addition, E2F and LXCXE binding are not the only mechanisms through which RB inhibits cell growth. The C pocket also contributes to RB-mediated growth suppression.

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