| Abstract: | In view of modern knowledge and concepts about components, function and mechanisms of response of cell molecular structures to damaging effects, response which is generating specialized modules of reactions, it is shown that main components of the mechanism of maintenance of genome constancy at ionizing radiation exposure are checkpoints of cell cycle, DNA repair and apoptosis. They operate under the control of a genetic system at participation of Tp53 gene, corresponding protein and of regulatory networks formed by cascades of mitogen-activated protein kinases (MAPK). At ionizing radiation exposure the MAPK special modules participate in formation of radiation effect: ERK 1/2 (extracellular signal-regulated kinase 1 and 2), JNK/SAPK (c-Jun N-terminal kinase/stress activated protein kinase) and p38 MAPK. Executing physiological functions of maintenance of normal life activity of cells, they do not lose this capacity after exposure to ionizing radiation, participating in formation of radiation effect in a wide range of doses, and are inactivated only by exposure to very high doses. It is concluded that in light of the modern data the main problem is not a problem of mechanisms of biological effect of ionizing radiation but a problem of biological mechanisms of radiation exposure. |
