A proton-translocating ATPase complex, also known as the V-ATPase complex, is a protein complex found in the membrane of various cellular compartments in eukaryotic cells. It performs the critical role of ATP hydrolysis coupled with proton translocation across biological membranes, enabling the transport of ions and molecules against their concentration gradients.
The proton-translocating ATPase complex consists of two main components: a peripheral V1 domain located in the cytosol and an integral V0 domain embedded in the membrane. The V1 domain consists of several subunits, often denoted as A-H, responsible for ATP hydrolysis. In contrast, the V0 domain comprises several subunits, commonly known as a, c, c', d, and e, involved in proton translocation.
The V-ATPase complex generates a proton gradient across the membrane, typically from the cytoplasm to various cellular compartments, such as lysosomes, endosomes, and Golgi apparatus. This gradient plays crucial roles in a variety of cellular functions, including pH regulation, intraorganellar trafficking, protein degradation, neurotransmitter release, and bone resorption.
Despite its universal function, the proton-translocating ATPase complex may exhibit specific structural and functional variations depending on the cellular compartment it is found in. These variations allow for the diverse requirements of different subcellular compartments and contribute to the overall integrity and functionality of the complex.
