Dynamics of micronuclei regulated by the cytosolic DNA sensor cGAS

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19467
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 50:Oncology and related fields
• Research Institution: Japanese Foundation for Cancer Research
• Principal Investigator: KITAJIMA Shunsuke 公益財団法人がん研究会, がん研究所 細胞生物部, 研究員 (90566465)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: cGAS / 新規リン酸化

Outline of Final Research Achievements

We have previously demonstrated that micronuclei induced by inhibition of spindle assembly checkpoint (SAC) are recognized by cGAS as ectopic DNA in the cytoplasm, thereby triggering antiviral response and anti-tumor immune pathways. In this study, we found that a novel and functionally unknown phosphorylation in the cGAS protein was induced during the induction of micronuclei following SAC inhibition. By utilizing Phostag technology to analyze cGAS phosphorylation under various conditions, we optimized cell culture conditions to efficiently induce this novel cGAS phosphorylation. Additionally, we established optimal conditions for cell lysate preparation and identified suitable tags for immunoprecipitation to concentrate and identify phosphorylation sites on the cGAS protein. Next, we plan to identify these phosphorylation sites using phosphoproteomics and analyze their impact on anti-tumor immune pathways.

Free Research Field

腫瘍生物学

Academic Significance and Societal Importance of the Research Achievements

がん細胞において染色体不分離に伴い発生する微小核は核膜の修復能力が低く、内包する染色体が細胞質に露出することで、cGAS依存的に抗腫瘍免疫を誘導する。微小核の一部はその後消失することが知られているが、その制御機構はほとんど解明されていない。本研究では、研究代表者らが見出した微小核誘導時に出現する機能不明なcGASのリン酸化が、cGASによる微小核の認識および分解に寄与するという仮説のもと、新規リン酸化部位を特定し、微小核とcGASとの相互作用やその下流シグナルである抗ウイルス応答/抗腫瘍免疫経路への影響を解明することで、自己DNA依存的な免疫応答機構に関する新たな知見が得ることができる。