Intracellular redox compartments: mechanisms and significances.

With the appearance of oxygen and the development of aerobic life on earth, reactive oxygen species (ROS) became important factors influencing a number of processes within a cell. Although initially considered unwanted and harmful by-products of a number of cellular reactions, the last decade has shown that ROS can also act as signalling molecules mediating changes in O(2) tension, as well as the response to hormones, growth factors, and mechanical or chemical stress. Different ROS-generating and ROS-degrading systems in different intracellular compartments seem to play an important role. In line with this, it appears that proteins already well known for an ROS-unrelated specific function in one compartment participate in the ROS response within another compartment. Thus, it is easy to envision that redox changes in different compartments and resulting changes in ROS levels may represent an important mechanism of intracellular communication between different cellular compartments.