JAK2-CHK2 signaling safeguards the integrity of the mitotic spindle assembly checkpoint and genome stability

• Published in: Cell death & disease Vol. 13; no. 7; p. 619
• Main Authors: Chowdhury, Md Al Nayem, Wang, Shih-Wei, Suen, Ching-Shu, Hwang, Ming-Jing, Hsueh, Yi-An, Shieh, Sheau-Yann
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.07.2022; Springer Nature B.V; Nature Publishing Group
• Subjects: 101/58; 14; 14/19; 631/67/69; 631/80/86/2371; 96; 96/95; Antibodies; Biochemistry; Biomedical and Life Sciences; Cell Biology; Cell Culture; Cell Cycle Proteins - metabolism; Checkpoint Kinase 2 - genetics; Checkpoint Kinase 2 - metabolism; CHK2 protein; Deficient mutant; Genomes; Genomic Instability; Humans; Immunology; Janus kinase 2; Janus Kinase 2 - genetics; Janus Kinase 2 - metabolism; Kinetochores - metabolism; Life Sciences; Localization; M Phase Cell Cycle Checkpoints - genetics; Mitosis - genetics; Phosphorylation; Phosphorylation - physiology; Protein Serine-Threonine Kinases; Spindle Apparatus - genetics; Spindle Apparatus - metabolism
• DOI: 10.1038/s41419-022-05077-0
• ISSN: 2041-4889

Checkpoint kinase 2 (CHK2) plays an important role in safeguarding the mitotic progression, specifically the spindle assembly, though the mechanism of regulation remains poorly understood. Here, we identified a novel mitotic phosphorylation site on CHK2 Tyr156, and its responsible kinase JAK2. Expression of a phospho-deficient mutant CHK2 Y156F or treatment with JAK2 inhibitor IV compromised mitotic spindle assembly, leading to genome instability. In contrast, a phospho-mimicking mutant CHK2 Y156E restored mitotic normalcy in JAK2-inhibited cells. Mechanistically, we show that this phosphorylation is required for CHK2 interaction with and phosphorylation of the spindle assembly checkpoint (SAC) kinase Mps1, and failure of which results in impaired Mps1 kinetochore localization and defective SAC. Concordantly, analysis of clinical cancer datasets revealed that deletion of JAK2 is associated with increased genome alteration; and alteration in CHEK2 and JAK2 is linked to preferential deletion or amplification of cancer-related genes. Thus, our findings not only reveal a novel JAK2-CHK2 signaling axis that maintains genome integrity through SAC but also highlight the potential impact on genomic stability with clinical JAK2 inhibition.