Synthesis of adenosine triphosphate in isolated nuclei and intact cells

Abstract

1. It has previously been demonstrated that nuclei isolated from normal and neoplastic lymphoid cells are capable of oxygen-dependent ATP synthesis. In this paper it is shown that also the corresponding intact cells can synthesize ATP under those conditions in which nuclei can synthesize ATP. 2. In nuclei isolated from liver, kidney, rhabdomyosarcoma and osteosarcoma, oxygen-dependent ATP synthesis could not be demonstrated. The cells isolated from these tissues or tumours could not synthesize ATP either. The alternatives that such nuclei lost their ability for oxidative phosphorylation during the isolation procedure or that the process does not occur in these nuclei were explored. 3. Janus Green B, a vital stain for mitochondria, was used as a differential inhibitor of mitochondrial and nuclear ATP synthesis in intact cells. 4. Oxidative phosphorylation in mitochondria isolated from cells that had been incubated with various concentrations of Janus Green B (1-10mum) was seriously uncoupled, whereas at these concentrations oxygen-dependent ATP synthesis in isolated nuclei and in isolated cells were only inhibited to a small extent. 5. The results suggest that oxygen-dependent ATP synthesis in isolated cells measured under ;nuclear' conditions and in the presence of Janus Green B and Ca(2+) is mainly due to nuclear oxygen-dependent ATP synthesis. The stimulation of cellular ATP synthesis by glucose was completely inhibited by Janus Green B. 6. It is tentatively concluded that the stimulation of ATP synthesis in isolated cells by glucose, which is not found in isolated nuclei, represents mitochondrial ATP synthesis, and nuclear and mitochondrial ATP synthesis can then be studied differentially in the intact cell. The possibility is considered that oxygen-dependent nuclear ATP synthesis is not a general property of cell nuclei.

RNAi Factors Are Present and Active in Human Cell Nuclei

“…We also confirmed that similar amounts of Ago2 were immunoprecipitated from both extracts in our experiments ( Figure S5D ). Nuclear extracts are unlikely to support efficient ATP regeneration for some RNAi processes ( Klouwen and Appelman, 1967 ; Zamore et al, 2000 ). Since RISC loading has been reported to require ATP ( Iwasaki et al, 2010 ), we used phosphocreatine and creatine kinase ( Calhoun and Swartz, 2007 ) to regenerate ATP.…”

ADP-ribose derived Nuclear ATP is Required for Chromatin Remodeling and Hormonal Gene Regulation (97 charact)

“…Although this may be the case in steady state situations, the question remains about the source of energy for extensive or sudden changes in chromatin. Nearly 60 years ago Allfrey and Mirsky proposed that ATP could be generated in isolated nuclei 2, 3 . It was suggested that the substrate for nuclear oxidative phosphorylation was in part generated by the ribose pathway 4 .…”

Efficient extra‐mitochondrial aerobic ATP synthesis in neuronal membrane systems

“…An ATP synthesis outside the mitochondrion has long been known to occur in the cell nuclei, devoid of mitochondria (Klouwen & Appelman, 1967). In recent years, several biochemical, proteomics, and immunofluorescence studies demonstrated that ATP synthase, and sometimes the ETC, are also expressed in extra‐mitochondrial membranes (Bartoli et al., 1975; Panfoli, Ravera, et al., 2011), such as the plasma membrane of several cancer cell types (Chang et al., 2012; Jung et al., 2007; Ravera, Aluigi, et al., 2011; Stockwin et al., 2006; Yamamoto et al., 2007; Young, 2010) and lipid rafts (Panfoli, Ravera, et al., 2011).…”