Polo-like kinase 1 (PLK1) protects against genome instability by ensuring timely and accurate mitotic cell division, and its activity is tightly regulated throughout the cell cycle. Although the pathways that initially activate PLK1 in G2 are well-characterized, the factors that directly regulate mitotic PLK1 remain poorly understood. Here, we identify that human PLK1 activity is sustained by the DNA damage response kinase Checkpoint kinase 2 (Chk2) in mitosis.
View Article and Find Full Text PDFPolo-like kinase 1 (PLK1) protects against genome instability by ensuring timely and accurate mitotic cell division. PLK1 activity is tightly regulated throughout the cell cycle. Although the pathways that initially activate PLK1 in G2 are well-characterized, the factors that directly regulate PLK1 in mitosis remain poorly understood.
View Article and Find Full Text PDFThe human ataxia telangiectasia mutated and Rad3-related (ATR) kinase functions in the nucleus to protect genomic integrity. Micronuclei (MN) arise from genomic and chromosomal instability and cause aneuploidy and chromothripsis, but how MN are removed is poorly understood. Here, we show that ATR is active in MN and promotes their rupture in S phase by phosphorylating Lamin A/C at Ser395, which primes Ser392 for CDK1 phosphorylation and destabilizes the MN envelope.
View Article and Find Full Text PDFA drastic TRPA1 mutant (R919*) identified in CRAMPT syndrome patients has not been mechanistically characterized. Here, we show that the R919* mutant confers hyperactivity when co-expressed with wild type (WT) TRPA1. Using functional and biochemical assays, we reveal that the R919* mutant co-assembles with WT TRPA1 subunits into heteromeric channels in heterologous cells that are functional at the plasma membrane.
View Article and Find Full Text PDFCentromere protein A (CENP-A) defines centromere identity and nucleates kinetochore formation for mitotic chromosome segregation. Here, we show that ataxia telangiectasia and Rad3-related (ATR) kinase, a master regulator of the DNA damage response, protects CENP-A occupancy at interphase centromeres in a DNA damage-independent manner. In unperturbed cells, ATR localizes to promyelocytic leukemia nuclear bodies (PML NBs), which house the histone H3.
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