PIP30/FAM192A is a novel regulator of the nuclear proteasome activator PA28γ

PA28γ is a nuclear activator of the 20S proteasome involved in the regulation of several essential cellular processes, such as cell proliferation, apoptosis, nuclear dynamics, and cellular stress response. Unlike the 19S regulator of the proteasome, which specifically recognizes ubiquitylated proteins, PA28γ promotes the degradation of several substrates by the proteasome in an ATP- and ubiquitin-independent manner. However, its exact mechanisms of action are unclear and likely involve additional partners that remain to be identified. Here we report the identification of a cofactor of PA28γ, PIP30/FAM192A. PIP30 binds directly and specifically via its C-terminal end and in an interaction stabilized by casein kinase 2 phosphorylation to both free and 20S proteasome-associated PA28γ. Its recruitment to proteasome-containing complexes depends on PA28γ and its expression increases the association of PA28γ with the 20S proteasome in cells. Further dissection of its possible roles shows that PIP30 alters PA28γ-dependent activation of peptide degradation by the 20S proteasome in vitro and negatively controls in cells the presence of PA28γ in Cajal bodies by inhibition of its association with the key Cajal body component coilin. Taken together, our data show that PIP30 deeply affects PA28γ interactions with cellular proteins, including the 20S proteasome, demonstrating that it is an important regulator of PA28γ in cells and thus a new player in the control of the multiple functions of the proteasome within the nucleus

High long-term survival and asymmetric movements in a reintroduced metapopulation of Cinereous vultures

International audiencePost-release mortality and movements are top proximate factors of translocation failure. Yet, survival and movement reflect different demographic and behavioral processes and may therefore have contrasted responses to management, although they are often very difficult to disentangle in animal populations. To provide guidance in animal translocations, we discriminated the respective roles of survival and movement in the long-term dynamic of a translocated metapopulation of cinereous vultures (Aegypius monachus) in France using multi-event capture-recapture analyses of reintroduced (n=119) and wild-born individuals (n=163) observations. Annual apparent survival rates were high and structured in age (>0.8 for young and >0.9 for adults) and did not differ between individuals origin (wild-born or released), release methods (aviary or hacking) nor between regions (Alps and Causses), except for those released in the Alps experiencing a reduced survival for one year after release. In contrast, age structure movements differed between populations and origin status. Wild-born young from the Causses were more erratic than those from the Alps and older individuals, whereas vultures reintroduced in the Causses demonstrated restricted movements during their first year after release. Despite such asymmetric movements, we overall highlight a strong tropism of individuals whatever the region and their origin. Since movement and survival were respectively higher and lower in young compared to adults, we recommend to first release adults in the primary stage of metapopulation translocations for increasing the establishment success at the release site. Further releasing young and securing successful breeding into the wild would increase demographic growth and between population connections

Appendix A. Selection of the best tag loss and dispersal models in each site.

Selection of the best tag loss and dispersal models in each site