Cell proliferation

Cell proliferation , often just called proliferation ( Latin proles , “offspring”, “scion” and ferre “carry”), is the term for the rapid growth or reproduction of tissue. Cell proliferation manifests itself in cell division and cell growth .

description

Cells in a living organism are constantly dying . In the human body , for example, these are several hundred million cells per day. This loss has to be compensated for by the formation of new cells - cell proliferation.

The formation of new cells occurs through cell division. Complicated signal cascades (signal transduction) are necessary for the division to be controlled . Play messengers as mitogens and growth factors and hormones such as insulin or somatotropin , as a trigger the signaling cascade a decisive role. Among other things, ion channels for potassium and calcium , as well as the sodium proton exchanger (NHE) and other transport proteins are activated. The formation of inositol trisphosphate (a second messenger ) is stimulated, tyrosine kinases are activated and a series of kinase cascades is set in motion through the mediation of G proteins on the G protein-coupled receptor of the cell .

If individual elements of the signal cascade are inhibited, cell proliferation can be interrupted. Conversely, mutations in the genes of signaling proteins can cause cell proliferation to proceed in an uncontrolled manner. Proto-oncogenes mutate into oncogenes . These cause proliferation to start even without messenger substances, which means that the cell divides independently and in an uncontrolled manner. The fatal mutation is transferred to the daughter cells, which can then also continue to divide in an uncontrolled manner, which can ultimately lead to the development of degenerate tissue ( cancer ).

Example of proliferation

In the event of a vascular injury, the thrombocytes (blood platelets) release a mitogen, the Platelet Derived Growth Factor (PDGF). This growth factor triggers cell proliferation and thus enables the wound to heal. If the wound is closed, other messenger substances stop the proliferation again.

literature

• F. Lang, P. Lang: Basic knowledge of physiology. Verlag Springer, 2007, ISBN 978-3-540-71401-9 , p. 15.
• L. Stallion: regulation of cell proliferation. ( Memento of January 7, 2011 in the Internet Archive ) (PDF, 461 kB) Max Planck Institute for Biochemistry, Activity Report 2003.

Individual evidence

1. ^ L Claesson-Welsh: Mechanism of action of platelet-derived growth factor]. In: International Journal of Biochemistry and Cell Biology , 28 (4), 1996, pp. 373-385, PMID 9026349 .
2. ^ LT Williams: Signal transduction by the platelet-derived growth factor receptor. In: Science , 243 (4898), 1989, pp. 1564-1570, PMID 2538922 .