PICH regulates the abundance and localization of SUMOylated proteins on mitotic chromosomes

Proper chromosome segregation is essential for faithful cell division and if not maintained results in defective cell function caused by the abnormal distribution of genetic information. Polo-like kinase 1–interacting checkpoint helicase (PICH) is a DNA translocase essential for chromosome bridge resolution during mitosis. Its function in resolving chromosome bridges requires both DNA translocase activity and ability to bind chromosomal proteins modified by the small ubiquitin-like modifier (SUMO). However, it is unclear how these activities cooperate to resolve chromosome bridges. Here, we show that PICH specifically disperses SUMO2/3 foci on mitotic chromosomes. This PICH function is apparent toward SUMOylated topoisomerase IIα (TopoIIα) after inhibition of TopoIIα by ICRF-193. Conditional depletion of PICH using the auxin-inducible degron (AID) system resulted in the retention of SUMO2/3-modified chromosomal proteins, including TopoIIα, indicating that PICH functions to reduce the association of these proteins with chromosomes. Replacement of PICH with its translocase-deficient mutants led to increased SUMO2/3 foci on chromosomes, suggesting that the reduction of SUMO2/3 foci requires the remodeling activity of PICH. In vitro assays showed that PICH specifically attenuates SUMOylated TopoIIα activity using its SUMO-binding ability. Taking the results together, we propose a novel function of PICH in remodeling SUMOylated proteins to ensure faithful chromosome segregation

Annual Dynamics of a Layered Phytoplankton Structure in a Meromictic Lagoon Partially Isolated from the White Sea

In a saline semi-isolated lagoon on Cape Zeleny (White Sea), the annual dynamics of the vertical hydrological structure and the seasonal dynamics of phytoplankton were traced. Species composition, vertical distribution, abundance, nutrition type, and biomass were analyzed. In total, 293 species and supraspecific taxa of algae and cyanobacteria were found. Most of the identified species are marine, and 38 species are freshwater. Taxonomic composition changed in the lagoon throughout the year. Dinoflagellates dominated in winter and early June; unidentified cocci and flagellates in July; diatoms, dinoflagellates, and unidentified cells in August; dinoflagellates in September; and unidentified cocci and flagellates in October–November. The abundance of algae also changed in the lagoon throughout the year. The integrated biomass in the water column varied from 0.01 g C/m2 in January to 0.78 g C/m2 in early September. According to the environmental parameters, the water column of the lagoon was subdivided into several zones with different environmental conditions and corresponding phytoplankton communities. The similarity between the communities of different horizons was 32–46% in summer and 7% in winter. The chemocline layer was the most populous. It contained a maximum of phytoplankton biomass, 1–2 orders of magnitude higher than that in the overlying horizons. Despite the connection to the sea, the phytoplankton structure in the surface water layer in the lagoon and in the sea differed significantly in composition, quantitative parameters, and seasonal dynamics. The similarity between the communities never exceeded 50%. In terms of biomass dynamics, the lagoon lagged behind the sea until mid-summer, but, starting from August, it outnumbered it, and the phytoplankton development in the lagoon lasted longer, until late autumn. According to sequential tests DistLM, the phytoplankton structure and dynamics in the lagoon and in the sea were related to the daylength, water salinity, oxygen content, and pH by 24.5%. At the same time, the PhP structure did not depend on water temperature, underwater illuminance, or depth. Oxygen content and pH were defined by PhP activity. Salinity serves as a vector of the vertical sequence of ecological niches. The day length seems to be the crucial factor of the seasonal PhP dynamics in the semi-isolated coastal stratified lakes and lagoons

Actin-binding protein alpha-actinin 4 (ACTN4) is a transcriptional co-activator of RelA/p65 sub-unit of NF-kB

ACTN4 is an actin-binding protein that participates in cytoskeleton organisation. It resides both in the cytoplasm and nucleus and physically associates with various transcription factors. Here, we describe an effect of ACTN4 expression on transcriptional activity of the RelA/p65 subunit of NF-kB. We demonstrate that ACTN4 enhances RelA/p65-dependant expression of c-fos, MMP-3 and MMP-1 genes, but it does not affect TNC, ICAM1 and FN1 expression. Importantly, actin-binding domains of ACTN4 are not critical for the nuclear translocation and co-activation of RelA/p65-dependent transcription. Collectively, our data suggest that in the nucleus, ACTN4 functions as a selective transcriptional co-activator of RelA/p65.Funding Agencies|FEBS Collaborative Experimental Scholarship for Central and Eastern Europe||RFBR|12-04-32194 mol_a10-04-0017412-04-32252 mol_a|Russian Government Programme for the Recruitment of the leading scientists into the Russian Institutions of Higher Education|11.G34.31.0069|Federal Target Program - Scientific and Pedagogical staff of innovative Russia|Pi174|Federal Programme for Scientific training in Innovative Russia|8280|</p

Correction: Actin-binding protein alpha-actinin 4 (ACTN4) is a transcriptional co-activator of RelA/p65 sub-unit of NF-kB (vol 4, pg 362, 2013)

[This corrects the article DOI: 10.18632/oncotarget.901.]

Self-regulated learning activity skills formation in the Montessori primary school

ACTN4 is an actin-binding protein that participates in cytoskeleton organisation. It resides both in the cytoplasm and nucleus and physically associates with various transcription factors. Here, we describe an effect of ACTN4 expression on transcriptional activity of the RelA/p65 subunit of NF-kB. We demonstrate that ACTN4 enhances RelA/p65-dependant expression of c-fos, MMP-3 and MMP-1 genes, but it does not affect TNC, ICAM1 and FN1 expression. Importantly, actin-binding domains of ACTN4 are not critical for the nuclear translocation and co-activation of RelA/p65-dependent transcription. Collectively, our data suggest that in the nucleus, ACTN4 functions as a selective transcriptional co-activator of RelA/p65.Funding Agencies|FEBS Collaborative Experimental Scholarship for Central and Eastern Europe||RFBR|12-04-32194 mol_a10-04-0017412-04-32252 mol_a|Russian Government Programme for the Recruitment of the leading scientists into the Russian Institutions of Higher Education|11.G34.31.0069|Federal Target Program - Scientific and Pedagogical staff of innovative Russia|Pi174|Federal Programme for Scientific training in Innovative Russia|8280|</p

Actin-binding protein alpha-actinin 4 (ACTN4) is a transcriptional

Actin-binding protein alpha-actinin 4 (ACTN4) is a transcriptional co-activator of RelA/p65 sub-unit of NF-k