What proteins in the cells are able to control the expression of certain neurological disease, thus preventing the deterioration of the cells?
Answers
The human brain is a highly complex organ with remarkable energy demands. Although it represents only 2% of the total body weight, it accounts for 20% of all oxygen consumption, reflecting its high rate of metabolic activity. Mitochondria have a crucial role in the supply of energy to the brain. Consequently, their deterioration can have important detrimental consequences on the function and plasticity of neurons, and is thought to have a pivotal role in ageing and in the pathogenesis of several neurological disorders. Owing to their inherent physiological functions, mitochondria are subjected to particularly high levels of stress and have evolved specific molecular quality-control mechanisms to maintain the mitochondrial components. Here, we review some of the most recent advances in the understanding of mitochondrial stress-control pathways, with a particular focus on how defects in such pathways might contribute to neurodegenerative disease.
Mitochondria are energy-converting organelles that are present in the cells of virtually all eukaryotic organisms. These cellular powerhouses use oxygen to harness energy through the oxidative phosphorylation (OXPHOS) process. To achieve this, high-energy electrons derived from the oxidation of food molecules are transferred along the respiratory chain (RC) to four multisubunit protein complexes embedded in the inner mitochondrial membrane, releasing energy that is used to pump protons across this membrane. The established proton gradient and resulting mitochondrial membrane potential (Δψm) are then used by adenosine triphosphate (ATP) synthetase to generate ATP, which provides the cell with the majority of its energy requirements. This process of energy production was developed by bacteria approximately two billion years ago, before the appearance of eukaryotic cells. According to the endosymbiotic theory, mitochondria were once aerobic bacteria that united with the ancestor of the eukaryotic cell in a mutually advantageous relationship, and this led to an evolutionary explosion from which multicellular organisms evolved (Ref. 1).