ATPases are a class of enzymes that catalyze ATP hydrolysis to dephosphorylate adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and release energy through active transport. There are different types of ATPases: (1) Vacuolar-type H+-ATPases (V-ATPases), which are found within the membranes of many organelles, such as endosomes, lysosomes, and secretory vesicles in eukaryotic cells, and which catalyze ATP hydrolysis to proton transport across intracellular and plasma membranes. In nervous system, V-ATPase acidifies synaptic vesicles to release chemicals (neurotransmitters) for neuronal signal communication between the nervous cells. They are also found in the plasma membranes of a wide variety of cells such as intercalated cells of the kidney, osteoclasts (bone-resorbing cells), macrophages, neutrophils, sperms, and certain tumor cells. (2) Plasma membrane H+-ATPases, P-ATPases (E1E2-ATPases), which are found in bacteria, fungi, eukaryotic plasma membranes, and organelles, function to transport a variety of different ions across membranes. An important example of food digestion is the hydrogen–potassium transporter (H+/K+ATPase or gastric proton pump) that acidifies the contents of the stomach by pumping hydrogen ion into the stomach.
This handbook presents the scope of vacuolar H+-ATPases and plasma membrane H+-ATPases through contributions by leading experts in the area of basic science and clinical medicine. Their expertise in biochemistry, cell biology, and pathophysiology has greatly added to bring forth the most recent results to our readers. This book is the first of its kind to summarize an essential link between vacuolar H+-ATPase and the glycolysis metabolic pathway that helps to understand the mechanism of diabetes and the metabolism of cancer cells. This book presents recent findings on the structure and function of vacuolar H+-ATPase in glucose-promoting assembly and in glucose signaling, in addition to describing the regulatory mechanisms of vacuolar H+-ATPase in yeast cells, neural stem cells, kidney cells, cancer cells, as well as under diabetic conditions. This book also provides information pertaining to the role of V-ATPase on insulin secretion and cancer chemotherapy. It also illustrates the activation of plasma membrane H+-ATPase through glucose-induced calcium signaling in Saccharomyces cerevisiae yeast cells.
"The book presents the most up-to-date comprehensive review on the significance of V-ATPase function and its recently recognized involvement in signal transduction provided by leading experts in the field. It will be a very useful resource to established investigators working in the field of V-ATPase as well as to those new to the field."
~Dr. Souad R. Sennoune, Texas Tech University Health Sciences Center, USA
“Dr. Nakamura has recruited top researchers in the field to provide a current view of the structure and function of vacuolar H+-ATPases (V-ATPases). V-ATPases are vital in the physiology of eukaryotic cells in general and specialized versions of V-ATPase are critical for disease processes ranging from cancer to bone disease. This book is particularly valuable for its chapters on emerging evidence linking V-ATPase to glucose metabolism and diabetes. I recommend Handbook of H+-ATPases as a valuable current survey of the field for the uninitiated and to provide a fresh perspective for the more seasoned investigator.”
~Dr. L. Shannon Holliday, University of Florida, USA
"This handbook focuses on our current knowledge of the structure, function, and regulation of the enzymes called H+-ATPases. It is particularly dedicated to vacuolar-type ATPase (V-ATPase), which is the key enzyme involved in acidification of intracellular compartments and extracellular milieu in both health and disease. Evolutionarily, eukaryotic V-ATPases are related to F-ATPsynthases, found in the inner mitochondrial membranes of eukaryotes and the plasma membranes of eubacteria, as well as to A-ATPsynthases, found in the plasma membranes of archaea and some eubacteria. Importantly, all these ATPases/ATPsynthases are structurally related and function as a marvelous rotary proton-pumping nanomotor, invented by Nature billions of years ago. However, during the evolution, from yeast to human, the eukaryotic V-ATPases have acquired some unique features including (i) self-regulation by assembly/disassembly, (ii) modulation of signaling and trafficking of crucial cellular receptors, and (iii) functioning as pH-sensing and signaling receptor. In this timely and comprehensive handbook all these features and other functions of V-ATPase are analyzed from cell biological and pathophysiological perspectives. Finally, the emerging role of V-ATPase as a drug target, to treat the variety of human diseases, such as cancer and diabetes as well as neurological and kidney disorders and their complications, is also thoroughly discussed in the book."
~Dr. Vladimir Marshansky, Massachusetts General Hospital and Harvard Medical School, USA