ARF triggers senescence in Brca2-deficient cells by altering the spectrum of p53 transcriptional targets.

ARF is a tumour suppressor activated by oncogenic stress, which stabilizes p53. Although p53 is a key component of the response to DNA damage, a similar function for ARF has not been ascribed. Here we show that primary mouse and human cells lacking the tumour suppressor BRCA2 accumulate DNA damage, which triggers checkpoint signalling and ARF activation.

ATM/ATR checkpoint activation downregulates CDC25C to prevent mitotic entry with uncapped telomeres.

Shelterin component TRF2 prevents ATM activation, while POT1 represses ATR signalling at telomeres. Here, we investigate the mechanism of G2/M arrest triggered by telomeres uncapped through TRF2 or POT1 inhibition in human cells. We find that telomere damage-activated ATR and ATM phosphorylate p53, as well as CHK1 and CHK2, thus activating two independent pathways to prevent progression into mitosis with uncapped telomeres.

RAD51 paralogs: roles in DNA damage signalling, recombinational repair and tumorigenesis.

Chromosomal double-strand breaks (DSBs) have the potential to permanently arrest cell cycle progression and endanger cell survival. They must therefore be efficiently repaired to preserve genome integrity and functionality. Homologous recombination (HR) provides an important error-free mechanism for DSB repair in mammalian cells.

A HIF-regulated VHL-PTP1B-Src signaling axis identifies a therapeutic target in renal cell carcinoma.

Metastatic renal cell carcinoma (RCC) is a molecularly heterogeneous disease that is intrinsically resistant to chemotherapy and radiotherapy. Although therapies targeted to the molecules vascular endothelial growth factor and mammalian target of rapamycin have shown clinical effectiveness, their effects are variable and short-lived, underscoring the need for improved treatment strategies for RCC. Here, we used quantitative phosphoproteomics and immunohistochemical profiling of 346 RCC specimens and determined that Src kinase signaling is elevated in RCC cells that retain wild-type von Hippel-Lindau (VHL) protein expression.

The chemoselective one-step alkylation and isolation of thiophosphorylated cdk2 substrates in the presence of native cysteine.

The elucidation of signalling pathways relies heavily upon the identification of protein kinase substrates. Recent investigations have demonstrated the efficacy of chemical genetics using ATP analogues and modified protein kinases for specific substrate labelling. Here we combine N(6) -(cyclohexyl)ATPγS with an analogue-sensitive cdk2 variant to thiophosphorylate its substrates and demonstrate a pH-dependent, chemoselective, one-step alkylation to facilitate the detection or isolation of thiophosphorylated peptides.