Electron transport chain components (ETC)

The electron transport chain (ETC) is a series of multi-subunit protein complexes (Complex I through IV) and mobile electron carriers (ubiquinone and cytochrome c) located within the inner mitochondrial membrane (StatPearls: Mitochondrial Electron Transport Chain). Its primary biological function is to facilitate the transfer of electrons from NADH and FADH2 to molecular oxygen, a process coupled with the pumping of protons into the intermembrane space to create an electrochemical gradient (UniProt: OXPHOS). This gradient drives the synthesis of ATP by Complex V (ATP synthase), providing the majority of energy for aerobic cells. Dysfunction of the ETC is a hallmark of mitochondrial myopathies and is heavily implicated in the progression of neurodegenerative diseases like Parkinson's and Alzheimer's, as well as metabolic disorders such as type 2 diabetes (PubMed: PMC4561404). In oncology, certain cancer cells rely on specific ETC components for survival, making them targets for novel inhibitors like IACS-010759. Clinically, drugs like metformin exert their primary glucose-lowering effects through the mild inhibition of Complex I, while the antiprotozoal atovaquone targets the fungal/parasitic ETC (PubChem: Metformin, Atovaquone). However, because the ETC is essential for systemic energy production, therapeutic targeting is often limited by the risk of severe side effects, most notably lactic acidosis and oxidative stress.

Other names

Respiratory chainOxidative phosphorylation systemOXPHOSMitochondrial electron transport chain

Inhibition of specific mitochondrial respiratory complexes (I, II, III, or IV) or ATP synthase (Complex V) to disrupt the proton gradient and ATP production.