Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly developed enzyme-cytochemistry (copper-ferro-cyanide) method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithe-lial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture. 243 Accepted: 2/04/02

Demonstration of glucose-6-phosphate dehydrogenase in rat Kupffer cells by a newly-developed ultrastructural enzyme-cytochemistry

“…Thus, the subcellular localization of this enzyme within Kupffer cells remained to be determined. Here, ultrastructural enzyme-cytochemistry has for the first time demonstrated the subcellular localization of Kupffer cell G6PD, consistent with findings in other cells including rat hepatocytes (Ishibashi et al 1999), human placental villous trophoblasts (Matsubara et al 2001a), human fetal membrane chorion laeve cytotrophoblasts (Matsubara et al 2001b), and rat lung alveolar type II epithelial cells (Matsubara et al 2002). Biochemical (Ozols 1993) and immunoelectron microscopic (Ninfali et al 2000) analysis also indicated that G6PD resided both in cytoplasm and in close association with the ER in rabbit hepatocytes and rat central nervous system neurons, respectively.…”

Definitive localization of intracellular proteins: Novel approach using CRISPR-Cas9 genome editing, with glucose 6-phosphate dehydrogenase as a model

“…To address the issue of native monomers dimerizing with mutant fluorescent monomers (see Figure 1), we chose to use G6PD, which forms homodimers as well as tetramers, as a model for studying subcellular localization. G6PD has long been considered almost exclusively a cytoplasmic protein [16–19]. In our previous study [4], we showed G6PD localization in the nucleus based on antibody studies and, indirectly, by enzymatic activity (i.e., NOX4 activity dependent on G6PD activity in nuclei).…”

“…The precise physiological states resulting in altered GmCh locations are currently being investigated in our laboratory. The locations observed for GmCh are highly likely to be reflective of wild-type native G6PD localization because (1) fluorescent tags only rarely change a protein’s native subcellular localization [20], and (2) the large majority of cells demonstrated at least some cytoplasmic localization of GmCh as predicted based on previous literature describing G6PD localization in the cytoplasm [16, 21]. …”

Compounds from Terminalia mantaly L. (Combretaceae) Stem Bark Exhibit Potent Inhibition against Some Pathogenic Yeasts and Enzymes of Metabolic Significance

“…Ribose-5-phosphate is used in DNA or RNA synthesis in cell reproduction, and NADPH is used as a coenzyme for the enzymes participating in the production of reduced glutathione. Given its role in cell growth, this enzyme is of high importance to mammal cells [ 19 , 20 ]. However, several studies have shown that this enzyme has an important role in the pathology of some diseases like cancer, hypertension, heart failure and type 2 diabetes.…”