Compartmentalized ATP pools produced from adenosine are nuclear pools.

Area of Science:

• Cellular and Molecular Biology
• Biochemistry
• Cancer Research

Background:

• Cellular energy metabolism involves adenine nucleotides, including adenosine triphosphate (ATP).
• Nuclear ATP levels and their ratios with adenosine diphosphate (ADP) may play roles in cellular processes.
• Cell transformation can alter nucleotide metabolism and compartmentalization.

Purpose of the Study:

• To investigate the effect of adenosine on nuclear adenine nucleotide pools.
• To compare the effects of adenosine with other adenine precursors.
• To examine the influence of cell transformation on adenosine-induced nuclear ATP changes.

Main Methods:

• Incubation of African green monkey kidney (BS-C-1) cells and mouse fibroblasts (3T6) with adenosine.
• Measurement of nuclear adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels.
• Comparison of adenosine effects with adenine and inosine treatments.
• Analysis of nucleotide pools in transformed versus untransformed cells.

Main Results:

• Adenosine significantly increased nuclear ATP levels and ATP/ADP ratios in BS-C-1 and 3T6 cells.
• Adenine and inosine increased total cellular ATP but did not affect nuclear ATP levels similarly.
• Adenosine-induced nuclear ATP increases were higher in untransformed BS-C-1 cells compared to transformed 3T6 cells.
• Transformation of chick embryo fibroblasts with Rous sarcoma virus reduced adenosine-promoted nuclear ATP compartmentalization.

Conclusions:

• Adenosine specifically elevates nuclear ATP pools and ATP/ADP ratios, suggesting compartmentalized metabolic regulation.
• The observed differences between cell types and transformation status indicate a role for nuclear adenine nucleotides in growth control.
• Increased nuclear ATPase and adenosine 5'-monophosphate (AMP) deaminase activities during S-phase suggest a mechanism for regulating nuclear ATP levels to favor DNA replication.