Aurora A is involved in central spindle assembly through phosphorylation of Ser 19 in P150Glued

A human Aurora A kinase engineered to be specifically inhibited by the ATP analog 1-Na-PP1 allows dissection of a novel role for this protein in central spindle assembly.

Knowledge of Aurora A kinase functions is limited to premetaphase events, particularly centrosome maturation, G2/M transition, and mitotic spindle assembly. The involvement of Aurora A in events after metaphase has only been suggested because appropriate experiments are technically difficult. We report here the design of the first human Aurora A kinase (as-AurA) engineered by chemical genetics techniques. This kinase is fully functional biochemically and in cells, and is rapidly and specifically inhibited by the ATP analogue 1-Naphthyl-PP1 (1-Na-PP1). By treating cells exclusively expressing the as-AurA with 1-Na-PP1, we discovered that Aurora A is required for central spindle assembly in anaphase through phosphorylation of Ser 19 of P150Glued. This paper thus describes a new Aurora A function that takes place after the metaphase-to-anaphase transition and a new powerful tool to search for and study new Aurora A functions.

Cell context-dependent involvement of ATR in early stages of retroviral replication

Retroviral DNA integration leaves behind a single-strand DNA discontinuity at each virus:host DNA junction. It has long been proposed that cellular proteins detect and repair the integrated DNA and that failure to do so might lead to apoptotic cell death, but their identity remains unknown. PIKK family members ATM, DNA-PKcs and ATR have all been proposed to be important for HIV-1 replication, but these findings turned out to be very controversial. In order to clarify their role in retroviral replication, we analyzed the effect of pharmacological inhibitors and of a dominant-negative version of ATR on the replication of retroviruses in cell lines relevant to HIV-1 infection. Our data show that ATR and probably other PIKKs as well are involved in retroviral replication in some but not all cell lines and that ATR increases the frequency of retroviral transduction by a mechanism other than the enhancement of infected cell survival.