Título del libro: Gastrointestinal Disorders: Symptoms, Treatment And Prevention
Título del capítulo: Yeast plasma membrane and vacuolar H+- ATPases
NORMA SILVIA SANCHEZ SANCHEZ; DANIELA ELVIRA CASTRO GRANADOS; MARTHA EYDI RUSE CALAHORRA FUERTES; ANTONIO CALVIN PEÑA DIAZ;
Autores externos:
Idioma:
Inglés
Año de publicación:
2012
Resumen:
Yeast cells have been for a long time the preferred model for numerous studies on eukaryotic cells. One vital parameter analyzed in yeasts is homeostasis of the internal pH, usually considered as being controlled within very narrow limits. Two proton pumps, apparently functioning in a coordinated way, play a central role in this regulation; the plasma membrane H+-ATPase (Pma1p) and the vacuolar or intravesicular H+-ATPases (V-ATPases). Pma1p, a 100 kDa polypeptide, anchored in the external lipid bilayer by 10 transmembrane a-helices, is responsible for a massive pumping of protons out of the cell, providing the driving force for the acidification of the external medium and an increase of the internal pH, generating a large proton gradient, which drives numerous H+-dependent cotransporters. On the other hand, V-ATPases are multisubunit complexes, containing a peripheral V1 domain, responsible for ATP hydrolysis, and an integral V0 domain that carries out proton translocation into the vacuole or other internal vesicles. V-ATPases acidify intracellular compartments and, in special cases, transport protons across the plasma membrane. Intracellular V-ATPases are involved in both normal and disease processes. In spite of the major differences between localization and structure of Pma1p and V-ATPases, they share some similarities in regulation and function. For example, both are regulated by glucose and use ATP hydrolysis to pump protons out the cytosol, (to extracellular media or into organelles, respectively). Some authors proved that vma mutations result in important alterations on Pma1p activity, amount and localization in the plasma membrane. Mutations on V-ATPase provoke the delocalization of Pma1p to the vacuole, and a decrement in the amount and activity of Pma1p in the plasma membrane. This work offers a brief review about the structure and function of Pma1p and V-ATPase from yeast, with special emphasis on the role of both proton pumps in internal pH changes and/or regulation. Besides, a brief discussion will be presented on the role of the cytosolic pH and its correlation with glucose metabolism, glucose-signal dependent pathways and V-ATPase regulation. © 2012 Nova Science Publishers, Inc. All rights reserved.
Entidades citadas de la UNAM:
ISBN:
9781621009979
Editorial:
Nova Science Publishers, Inc. Nombre de la publicación:
Yeast plasma membrane and vacuolar H+- ATPases
Página inicial:
113
Página final:
146
Tipo de producto:
Capítulo de un Libro
