The ATM Ser49Cys Variant Effects ATM Function as a Regulator of Oncogene-Induced Senescence

Area of Science:

• Cellular Biology
• Cancer Genetics
• DNA Damage Response

Background:

• The ataxia-telangiectasia mutated (ATM) protein kinase is crucial for cell cycle checkpoints and DNA repair.
• A specific ATM variant, Ser49Cys (rs1800054), is linked to increased melanoma risk, but its functional impact remains unclear.

Purpose of the Study:

• To investigate the functional consequences of the ATM Ser49Cys variant on DNA damage signaling and cellular responses.
• To determine if this variant influences melanoma development or related genetic traits.

Main Methods:

• Assessed ATM-dependent signaling in response to DNA damage using patient-derived lymphoblastoid lines and primary melanocytic cells heterozygous for the variant.
• Evaluated the impact of the variant on oncogene-induced senescence.
• Performed genomic and Genome-Wide Association Studies (GWAS) analyses on melanoma, naevus, and skin color data.

Main Results:

• The ATM Ser49Cys variant maintained functional acute p53-dependent signaling following DNA damage.
• Expression of the variant allele reduced the efficacy of oncogene-induced senescence, indicating a defect in chronic stress response.
• No association was found between the variant and melanoma, naevus, or skin color through genomic and GWAS analyses.

Conclusions:

• The ATM Ser49Cys variant has minimal impact on acute DNA damage response but exhibits reduced function in chronic responses to oncogene overexpression.
• This modest loss of function suggests the variant may act as a modifier, influencing the effects of other genetic variants in ATM/p53 signaling pathways.