| 1. |
- Oredsson, Stina, et al.
(författare)
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Polyamine-Dependent Early Cellular Signals and Cell Proliferation
- 2006
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Ingår i: Polyamine Cell Signaling. - Totowa, NJ : Humana Press. - 9781597451451 - 9781588296252 ; , s. 41-50
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- When a resting cell is awakened to enter the cell cycle by mitogenic stimulation, a complex molecular machinery involving positive and negative regulation of cell-cycle progression is initiated. Part of the machinery is quite well-known. It involves receptors of various kinds, protein interactions, phosphorylation reactions, and molecular cascades carrying the signal to enter the cell cycle from the cell surface to the nucleus. In the nucleus, transcriptional activation results in an increased involvement of genes in the process. In the cytoplasm, translational and posttranslational mechanisms also have a part in the process. In this complex partly known molecular machinery, there are also molecules that not yet have been assigned a specific role; however, there are enough data to state that their role in normal cell-cycle progression is ubiquitous. The level of the polyamines—putrescine, spermidine, and spermine—are low in nonproliferating cells, but their levels increase early after mitogenic stimulation and these increases are necessary for normal rates of cell-cycle progression (1,2). In this chapter, the focus will be on the role of polyamines in early signaling processes that are required for normal cell-cycle progression.
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| 2. |
- Persson, Lo, et al.
(författare)
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Regulation of ornithine decarboxylase expression
- 2006
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Ingår i: Polyamine Cell signaling: Physiology, Pharmacology, and Cancer Research. - Totowa, NJ : Humana Press. - 9781588296252 ; , s. 399-414
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- It has become increasingly obvious during the last two decades that a multitude of cellular processes are highly dependent on adequate levels of polyamines (1–6). Too high concentrations of the polyamines are toxic to the cell and may induce cell death or apoptosis (7). On the other hand, too low concentrations may negatively affect anabolic events, such as the synthesis of DNA, RNA, and protein, eventually giving rise to cellgrowth arrest (6). Thus it is important for cells to maintain their polyamine concentrations within rather narrow limits. Polyamine homeostasis is achieved by a careful balance between synthesis, degradation, and uptake of the amines (3). The introduction of molecular techniques in studies concerning polyamine metabolism has revealed a complex network of regulatory mechanisms involved in the cellular control of polyamine levels.
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| 3. |
- Soulet, Denis, et al.
(författare)
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Role of polyamines in the control of the immune response in the brain
- 2006
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Ingår i: Polyamine cell signaling, Physiology, Pharmacology, and Cancer Research. - Totowa, NJ : Humana Press. - 9781588296252 ; , s. 279-292
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Polyamines are essential polycations involved in a large variety of biological functions, including modulation of the nucleic acid conformation, RNA export and their degradation, protein synthesis, eIF-5A posttranslational modification, signal transduction, cell growth and differentiation, and tumor progression ( 1 –bi3. These various aspects in the biology of polyamines are addressed in other sections of this book.
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