Protistan Diversity in the Arctic: A Case of Paleoclimate Shaping Modern Biodiversity?

The impact of climate on biodiversity is indisputable. Climate changes over geological time must have significantly influenced the evolution of biodiversity, ultimately leading to its present pattern. Here we consider the paleoclimate data record, inferring that present-day hot and cold environments should contain, respectively, the largest and the smallest diversity of ancestral lineages of microbial eukaryotes.We investigate this hypothesis by analyzing an original dataset of 18S rRNA gene sequences from Western Greenland in the Arctic, and data from the existing literature on 18S rRNA gene diversity in hydrothermal vent, temperate sediments, and anoxic water column communities. Unexpectedly, the community from the cold environment emerged as one of the richest observed to date in protistan species, and most diverse in ancestral lineages.This pattern is consistent with natural selection sweeps on aerobic non-psychrophilic microbial eukaryotes repeatedly caused by low temperatures and global anoxia of snowball Earth conditions. It implies that cold refuges persisted through the periods of greenhouse conditions, which agrees with some, although not all, current views on the extent of the past global cooling and warming events. We therefore identify cold environments as promising targets for microbial discovery

Kif18B interacts with EB1 and controls astral microtubule length during mitosis

Kif18B is a newly discovered plus-tip-tracking protein that is enriched on astral microtubule (MT) ends during early mitosis. Kif18B binds directly to EB1, and this interaction is required for proper localization of Kif18B and to control astral MT length

Dishevelled, a Wnt signalling component, is involved in mitotic progression in cooperation with Plk1

This study establishes multiple mitotic functions of Dishevelled that are mediated by interactions with Plk1 and Mps1. The work thus extends the number of Wnt-components regulating mitotis

Microtubule targeting agents: from biophysics to proteomics

This review explores various aspects of the interaction between microtubule targeting agents and tubulin, including binding site, affinity, and drug resistance. Starting with the basics of tubulin polymerization and microtubule targeting agent binding, we then highlight how the three-dimensional structures of drug-tubulin complexes obtained on stabilized tubulin are seeded by precise biological and biophysical data. New avenues opened by thermodynamics analysis, high throughput screening, and proteomics for the molecular pharmacology of these drugs are presented. The amount of data generated by biophysical, proteomic and cellular techniques shed more light onto the microtubule-tubulin equilibrium and tubulin-drug interaction. Combining these approaches provides new insight into the mechanism of action of known microtubule interacting agents and rapid in-depth characterization of next generation molecules targeting the interaction between microtubules and associated modulators of their dynamics. This will facilitate the design of improved and/or alternative chemotherapies targeting the microtubule cytoskeleton