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Cytoplasmic dynein-1, a microtubule (MT)-based motor protein, requires dynactin and a coiled-coil adaptor to form the processive dynein-dynactin-adaptor (DDA) complex^1,2. The roles of MTs and dynein regulator lissencephaly-1 (LIS1) in DDA assembly have remained elusive. Here we use cryo-electron microscopy to determine the structural basis of MT- and LIS1-mediated DDA assembly. We show that an adaptor-independent dynein-dynactin complex spontaneously forms on MTs with an intrinsic 2:1 stoichiometry in a highly efficient manner, driven by parallel alignment of dynein tails upon MT binding. Adaptors can wedge into and exchange within the assembled MT-bound dynein-dynactin complex; these processes are enabled by relative rotations between dynein and dynactin and facilitated by the dynein light-intermediate chains that assist the adaptor 'search' mechanism. Although LIS1 is dispensable for efficient DD(A)-MT assembly, its presence expands the conformational landscape of DD(A) assemblies on MTs. Cryo-electron microscopy reveals that LIS1 bridges dynactin p150^glued and dynein in both the closed Phi-like and open prepowerstroke states, stabilizing low-MT-affinity intermediates that tether dynein molecules in proximity to MTs and prime them for subsequent DD(A) assembly through alternative pathways. These findings demonstrate the dynamic adaptability of the dynein transport machinery and the coordinated roles of MTs and LIS1 in DDA assembly.

Centromeres ensure accurate chromosome segregation, yet their DNA evolves rapidly across eukaryotes leaving the origins of new centromere architectures unclear^1-4. The brewer's yeast Saccharomyces cerevisiae exemplifies this long-standing puzzle. Its centromeres shifted ancestrally from large, repeat-rich, epigenetically specified forms to the compact, genetically defined 'point' centromeres^1,5. How this transition occurred has remained unresolved⁶. Here we identify evolutionarily related 'proto-point' centromeres that provide a resolution to the evolutionary origins of point centromeres. Proto-point centromeres contain a single centromeric nucleosome positioned over an AT-rich core, accompanied by relaxed organization and sequence variability of flanking cis-elements. In two species, these proto-point centromeres lie within retrotransposon-derived repeat clusters, linking ancestral repeat-rich centromeres to genetically encoded ones. Comparative and phylogenetic analyses indicate that proto-point and point centromeres evolved in an ancestor with retrotransposon-rich centromeres. These results identify long-terminal-repeat retrotransposons, specifically Ty5 sequences, as the genetic substrate for point-centromere evolution and provide a mechanistic route by which an epigenetic centromere can become genetically specified. More broadly, they show how selfish elements can be co-opted to perform essential chromosomal functions.

Feed algorithms are widely suspected to influence political attitudes. However, previous evidence from switching off the algorithm on Meta platforms found no political effects¹. Here we present results from a 2023 field experiment on Elon Musk's platform X shedding light on this puzzle. We assigned active US-based users randomly to either an algorithmic or a chronological feed for 7 weeks, measuring political attitudes and online behaviour. Switching from a chronological to an algorithmic feed increased engagement and shifted political opinion towards more conservative positions, particularly regarding policy priorities, perceptions of criminal investigations into Donald Trump and views on the war in Ukraine. In contrast, switching from the algorithmic to the chronological feed had no comparable effects. Neither switching the algorithm on nor switching it off significantly affected affective polarization or self-reported partisanship. To investigate the mechanism, we analysed users' feed content and behaviour. We found that the algorithm promotes conservative content and demotes posts by traditional media. Exposure to algorithmic content leads users to follow conservative political activist accounts, which they continue to follow even after switching off the algorithm, helping explain the asymmetry in effects. These results suggest that initial exposure to X's algorithm has persistent effects on users' current political attitudes and account-following behaviour, even in the absence of a detectable effect on partisanship.

Dielectric polymers used in electrical energy storage require a combination of key metrics, including a high dielectric constant (K), low loss and high breakdown strength (E_b), all while being capable of operating at high temperatures^1-6. Decades of research into polymer-inorganic composites have achieved only limited success in reaching these goals^5,7,8. Here we introduce high-temperature immiscible blends of two dipolar polymers that, through nanophase separation, self-assemble into three-dimensional all-polymer nanocomposites. The resulting nanostructures induce coiled-chain morphology and large conformation changes, which, combined with relatively low rotational barrier and high dipole moments of both polymers, yield ultrahigh dielectric responses (K > 13) while maintaining a low loss (tanδ approximately 0.002) across a wide temperature range. Simultaneously, the nanostructured interfaces act as barriers for mobile charges, markedly reducing conduction losses at high fields and temperatures. The all-polymer three-dimensional nanocomposites with concurrently high K, high E_b and low loss deliver unprecedented discharged energy densities at elevated temperatures (18.7 J cm^-3, 15.1 J cm^-3 and 8.6 J cm^-3 at 150 °C, 200 °C and 250 °C, respectively). The approach is applicable to other immiscible dipolar blends, demonstrating its universality and tunability. This work addresses the urgent needs in electrical energy storage and provides a new paradigm towards high-energy-density polymer dielectrics over a broad temperature range.

Organic batteries using abundant and recyclable organic electrode materials provide a sustainable and environmentally friendly alternative to commercial lithium-ion batteries^1-5, which rely on resource-limited mineral-derived inorganic electrode materials^6-8. However, the practical use of organic batteries has been severely hindered by the intrinsic insulation and dissolution of organic electrode materials^9,10. Here we report practical organic batteries using an n-type conducting polymer cathode, poly(benzodifurandione) (PBFDO), which exhibits excellent mixed ionic and electronic transport and low solubility. The PBFDO cathode maintains its n-doped state throughout the electrochemical processes and exhibits stable and reversible redox characteristics, high electrical conductivities and significant lithium-ion diffusion coefficients, without the need for additional conductive additives. Consequently, ultrahigh-mass-loading polymer cathodes, with mass loadings up to 206 mg cm^-2, are realized, delivering a high areal capacity of 42 mAh cm^-2 and demonstrating robust cycling stability. Furthermore, practical 2.5 Ah lithium-organic pouch cells were fabricated, achieving an impressive energy density of 255 Wh kg^-1. Notably, the conducting polymer cathode operates efficiently over a wide temperature range from -70 °C to 80 °C and demonstrates excellent flexibility and safety, marking considerable potential for applications in extreme conditions and wearable electronics.

Asgard archaea were pivotal in the origin of complex cellular life¹. Heimdallarchaeia (a class within the phylum Asgardarchaeota) are inferred to be the closest relatives of eukaryotes. Limited sampling of these archaea constrains our understanding of their ecology and evolution^2,3, including their role in eukaryogenesis. Here we use massive DNA sequencing of marine sediments to obtain 404 Asgardarchaeota metagenome-assembled genomes, including 136 new Heimdallarchaeia and several novel lineages. Analyses of their global distribution revealed they are widespread in marine environments, and many are enriched in variably oxygenated coastal sediments. Detailed metabolic reconstructions and structural predictions suggest that Heimdallarchaeia form metabolic guilds that are distinct from other Asgardarchaeota. These archaea encode hallmark proteins of an aerobic lifestyle, including electron transport chain complex (IV), haem biosynthesis and reactive oxygen species detoxification. Heimdallarchaeia also encode novel clades of respiratory membrane-bound hydrogenases with additional Complex I-like subunits, which potentially increase proton-motive force generation and ATP synthesis. Thus, we propose an updated Heimdallarchaeia-centric model of eukaryogenesis in which hydrogen production and aerobic respiration may have been present in the Asgard-eukaryotic ancestor. This expanded catalogue of Asgard archaeal genomic diversity suggests that bioenergetic factors influenced eukaryogenesis and constitutes a valuable resource for investigations into the origins and evolution of cellular complexity.