Nucleotide imbalance decouples cell growth from cell proliferation

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Nucleotide metabolism is crucial for DNA replication and cell division.
• Cells must maintain precise nucleotide levels for proper growth and proliferation.
• The mechanisms by which cells sense and respond to nucleotide imbalances are not fully understood.

Purpose of the Study:

• To investigate how cells sense and respond to imbalanced nucleotide levels.
• To determine the role of nucleotide balance in cell cycle progression and proliferation.
• To identify the signaling pathways involved in managing nucleotide homeostasis.

Main Methods:

• Cell culture and proliferation assays.
• Analysis of nucleotide pools and DNA replication.
• Investigation of signaling pathways including mTORC1, Akt, AMPK, and ATR.

Main Results:

• Excess individual nucleotides inhibit proliferation by disrupting DNA replication precursors.
• Canonical growth pathways (mTORC1, Akt, AMPK) do not sense these imbalances.
• ATR-dependent replication stress signaling is activated during S phase to manage nucleotide imbalance and promote DNA replication.

Conclusions:

• Cells primarily sense nucleotide imbalances during S phase via replication stress pathways.
• ATR signaling is essential for survival and recovery from nucleotide imbalance.
• Imbalanced nucleotides disrupt the coordination between cell growth and cell division.