Mitochondria and Parkinson's disease: a complex (III) liaison

Neurodegenerative disorders are progressive diseases that cause irreversible damage and loss to neurons in specific brain areas. Examples of these disorders include Parkinson's disease, Alzheimer's disease, Multiple Sclerosis (MS), and Amyotrophic Lateral Sclerosis (ALS). These disorders share characteristics such as proteinopathies, selective neuronal vulnerability, and a complex interplay between genetic and environmental factors. The primary therapeutic goal for these conditions is...

Neurodegenerative disorders, such as Parkinson's Disease (PD), involve the gradual and irreversible destruction of neurons in particular brain areas. These disorders exhibit standard features like proteinopathies, selective vulnerability of some neurons, and an interaction of intrinsic properties, genetics, and environmental influences in neural injury.
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of...

Mitochondria are eukaryotic cellular organelles that are known to produce energy through a process called oxidative phosphorylation. Besides their primary function, mitochondria are involved in various cellular processes, including cell growth, differentiation, signaling, metabolism, and senescence. Age-related changes cause a decline in mitochondrial quality and integrity due to increased mitochondrial mutations and oxidative damage. Thus, aging can severely impact mitochondrial functions,...

A single mitochondrion is a bean-shaped organelle enclosed by a double-membrane system. The outer membrane of mitochondria is smooth and contains many porins - the integral membrane transporters. Porins enable free diffusion of ions and small uncharged molecules through the outer mitochondrial membrane but limit the transport of molecules larger than 5000 Daltons. Further, the outer mitochondrial membrane forms a unique structure called membrane contact sites with other subcellular organelles,...

Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...

The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...