Table Of Contents Page, PNAS Volume 123, Number 5
This Week in PNAS
Commentaries
Brief Report
Biological polymers often face a trade-off between stiffness, strength, and extensibility:
Materials that are strong and stiff tend to be brittle, while those that are elastic
and extensible usually lack strength. Here, we show that netcasting spiders (...
Physical Sciences
Applied Physical Sciences
Granular materials densify under repeated mechanical perturbations, nonequilibrium
dynamics that underlies many natural and industrial processes. Because granular relaxation
is governed by frictional contacts and energy dissipation, this aging behavior ...
An elastic spring network is an example of evolvable matter. It can be pruned to couple
separated pairs of nodes so that when a strain is applied to one of them, the other
responds either in-phase or out-of-phase. This produces two pruned networks, with
...
Motile microorganisms, like bacteria and algae, unify abilities like self-propulsion,
autonomous navigation, and decision-making on the micron scale. While recent breakthroughs
have led to the creation of synthetic microswimmers and nanoagents that can ...
Ubiquitous noise sources in quantum systems remain a key obstacle to building quantum
computers, necessitating the use of quantum error correction codes. Recently, error-correcting
codes tailored for noise-biased systems have been shown to offer high ...
Subcellular proteomics maps protein localization within restricted domains of a cell,
complementing high-resolution imaging by expanding the number of proteins that can
be profiled at once. Achieving this at depth from subcellular inputs remains ...
Biophysics and Computational Biology
Some mammals develop amyloid plaques and type 2 diabetes, much like humans, depending
on the sequence of their islet amyloid polypeptide (IAPP). In humans, IAPP forms a
toxic oligomer with a parallel β-sheet across residues 23FGAIL28S. Using two-...
Amyloid oligomers of the human islet amyloid polypeptide (hIAPP) are a likely cytotoxic
species driving β-cell death in type 2 diabetes, but their transient nature has precluded
atomic-level structural characterization. We obtained a high-resolution ...
Ribonucleotide reductase (RNR) is an essential enzyme that converts ribonucleotides
into deoxyribonucleotides, enabling DNA synthesis and repair in all living organisms.
Central to class Ia RNR activity is a long-range radical transport pathway spanning
Homomeric and heteromeric protein complexes are ubiquitous across all domains of life.
The evolutionary transition from homo- to hetero-oligomers by gene duplication and
chain specialization is widespread, yet it entails challenging requirements for ...
For proper segregation of chromosomes and successful cytokinesis, chromosomes must
first “congress”—gather in a tight plate near the spindle equator. Molecular mechanism(s)
of congression are not fully understood. Here we combine live-cell microscopy, ...
When studying a complex system, it is often useful to think of the system as a network
of interacting units. One can then ask if some properties of the entire network are
already explained by a small part of the network, a network motif. A famous example
...
Chemistry
Cyclic Voltammetry (CV) is the most commonly used method in electrochemistry to characterize
electrochemical reactions, usually involving macroscopic electrodes. Here, we demonstrate
an optical CV technique called opto-iontronic Microscopy, which is ...
Embedding light-responsive small molecules in a porous solid is a promising strategy
to achieve dynamic control over material properties. Powering these systems with low-energy
photons is essential for their future applications, since visible light, ...
In this work, we present a type of molecular dynamics simulation that aims at finding,
in a blind way, metastable states. Using only data coming from an initial unbiased
simulation, and with the help of an appropriately defined loss function, we compute
a ...
The emergence upon cooling of an ordered solid phase from a disordered liquid is a
remarkable example of self-assembly, which has also major practical relevance. Here,
we use a recently developed committor-based enhanced sampling method to explore the
...
Earth, Atmospheric, and Planetary Sciences
Machine learning holds great promise for classifying and identifying fossils, and
has recently been marshaled to identify trackmakers of dinosaur footprints and address
long-standing debates over whether some dinosaur tracks are the oldest birds or ...
Engineering
Body-centered cubic (bcc) alloys can achieve gigapascal-level yield strengths but
typically are limited in tensile ductility (<20%), contrasting sharply with elemental
metals (the largest elongation of ~50%). Multi-principal-element alloys offer vast
...
Utilizing tantalum (Ta) in superconducting circuits has led to significant improvements,
such as high qubit lifetime (T1) and quality factors in both qubits and resonators, suggesting that material optimization
plays an important role in the development ...
Fe metal–organic framework–derived heterojunction for metabolic diagnosis of thymic epithelial tumor
Thymic epithelial tumors (TETs), rare yet clinically significant malignancies, face
diagnostic challenges due to their occult presentation and lack of noninvasive risk-stratification
tools, leading to systemic overtreatment and poor prognoses for high-...
Environmental Sciences
The global transition to sustainable energy demands efficient lithium extraction from
brines. While electrochemical lithium extraction using LiMn2O4 (LMO) holds great promise, its practical application is hindered by mechanical degradation
caused by ...
The ocean is thought to be the terminal sink for per- and polyfluoroalkyl substances
(PFAS), persistent organofluorine chemicals used widely in modern commerce for decades.
Industry and stewardship programs phased out the most abundantly produced legacy ...
The hydrological functions of forests are well recognized, but their influence on
water storage and release dynamics remains poorly quantified. The fraction of young
water (
Physics
Nonequilibrium selection pressures were proposed for forming oligonucleotides with
rich functionalities encoded in their sequences, such as catalysis. Since phase separation
was shown to direct various chemical processes, we ask whether condensed phases ...
Our adaptive immune system relies on the persistence over long times of a diverse
set of antigen-experienced B cells to encode our memories of past infections and to
protect us against future ones. While longitudinal repertoire sequencing promises
to ...
In three-dimensional chiral magnets, skyrmions are line-like objects oriented parallel
to the applied magnetic field. The efficient coupling of magnetic skyrmion lattices
to spin currents and magnetic fields permits their dynamical manipulation. Here, we
...
Magnetoelectric coupling enables the manipulation of magnetization by electric fields
and polarization by magnetic fields. While typically found in heavy element materials
with large spin–orbit coupling, recent experiments on rhombohedral-stacked ...
Statistics
In light of continued foreign interference in the US presidential elections, where
undisclosed digital voter suppression advertising has been deployed, this study addresses
the questions of who is exposed to these ads and whether and how such exposure ...
Social Sciences
Demography
Improvements in wildlife husbandry mean that many zoo animals are living longer. This
has put pressure on the finite holding capacity of zoos, which has often been addressed
through a curtailing of reproduction to reduce population growth rates. Here, we ...
Political Sciences
Based on observational studies, conventional wisdom suggests that citizenship carries
economic benefits. We leverage a randomized experiment from New York where low-income
registrants with permanent residency who wanted to become citizens entered a ...
Social Sciences
In light of continued foreign interference in the US presidential elections, where
undisclosed digital voter suppression advertising has been deployed, this study addresses
the questions of who is exposed to these ads and whether and how such exposure ...
When people collaborate in groups, they routinely face collective action problems:
for the group effort to succeed, individuals need to cooperate despite any incentives
to defect. These problems can be modeled with public goods games. To facilitate such
...
Biological Sciences
Agricultural Sciences
DELLA proteins, members of the GRAS-domain family of transcriptional regulators, play
a crucial role in plant growth and development. They modulate transcription indirectly
via interactions with hundreds of transcription factors. The phytohormone ...
Baculoviruses are large DNA viruses that mainly infect insects. During infection,
viral egress from midgut cells and subsequent behavior changes lead to terminally
infected insects migrating to higher elevations on plant branches or tree limbs. However,
...
Whiteflies pose a major threat to crops worldwide, primarily because they transmit
begomoviruses with which they have evolved intricate mutualistic relationships. The
mutualisms are known to exacerbate whitefly invasions and drive widespread plant virus
...
Applied Biological Sciences
Improvements in wildlife husbandry mean that many zoo animals are living longer. This
has put pressure on the finite holding capacity of zoos, which has often been addressed
through a curtailing of reproduction to reduce population growth rates. Here, we ...
Biochemistry
Homomeric and heteromeric protein complexes are ubiquitous across all domains of life.
The evolutionary transition from homo- to hetero-oligomers by gene duplication and
chain specialization is widespread, yet it entails challenging requirements for ...
Memory requires experience-dependent alterations in the synaptic proteome. Chaperones
interface between the environment and the proteome. Manipulating J-domain protein
(JDP) chaperones, the most diverse family of chaperones, in a Drosophila neuronal ...
The general control nonderepressible 2 (GCN2) is a conserved stress-responsive protein
that plays a critical role in restoring cellular homeostasis in the integrated stress
response (ISR). In response to amino acid starvation or ribosome stalling and ...
The host cell cytoskeleton plays a critical role in the SARS-CoV-2 life cycle, though
the underlying mechanisms remain poorly understood. This study investigates the interaction
between the SARS-CoV-2 spike (S) protein and the cytoskeleton-associated ...
Biophysics and Computational Biology
Nonequilibrium selection pressures were proposed for forming oligonucleotides with
rich functionalities encoded in their sequences, such as catalysis. Since phase separation
was shown to direct various chemical processes, we ask whether condensed phases ...
The human cell surfaceome, integral to cell communication and disease mechanisms,
presents a prime target for therapeutic intervention. De novo protein binder design
against these cell surface proteins offers a promising yet underexplored strategy
for ...
Alpha-synuclein (αS) plays a central role in several neurodegenerative diseases. Although
predominantly neuronal, αS is also present in peripheral fluids such as serum and
cerebrospinal fluid (CSF), where it may contribute to disease propagation. However,
...
BK channels play essential roles in a wealth of physiological functions, including
regulating smooth muscle tone and neurotransmitter release. Its dysfunction, often
caused by loss-of-function mutations, can lead to severe phenotypes, including ataxia
and ...
Cell Biology
For proper segregation of chromosomes and successful cytokinesis, chromosomes must
first “congress”—gather in a tight plate near the spindle equator. Molecular mechanism(s)
of congression are not fully understood. Here we combine live-cell microscopy, ...
The myosin superfamily encompasses over 70 classes, each with multiple subclasses,
and exhibits substantial diversity in properties such as velocity, ATPase activity,
duty ratio, and directionality. This functional diversity enables the specialized
roles ...
RNAs transcribed from protein-coding gene loci are widely assumed to be translated
into proteins. However, intronic polyadenylation (IPA) occurring near the transcription
start site or within early introns can generate noncoding RNAs derived from protein-...
The spatial coordination between cellular organelles and metabolic enzyme assemblies
represents a fundamental mechanism for maintaining metabolic efficiency under stress.
While previous work has shown that membrane-bound organelles regulate metabolic ...
Developmental Biology
Subcellular proteomics maps protein localization within restricted domains of a cell,
complementing high-resolution imaging by expanding the number of proteins that can
be profiled at once. Achieving this at depth from subcellular inputs remains ...
Reelin is a secreted glycoprotein with roles in the development of the mammalian neocortex,
hippocampus, and cerebellum. This vertebrate signaling molecule also contributes to
adult brain function. Mammalian Reelin increases the complexity of Drosophila ...
ARGONAUTE (AGO) proteins are a highly conserved family of RNA-binding proteins that
play central roles in gene regulation and developmental processes across eukaryotes.
Although AGO family members have been extensively studied in animals and plants, where
...
Ecology
When studying a complex system, it is often useful to think of the system as a network
of interacting units. One can then ask if some properties of the entire network are
already explained by a small part of the network, a network motif. A famous example
...
Anthropogenic nitrogen (N) deposition comprising reduced (NHx) and oxidized (NOy) forms, differentially influences ecosystem processes. However, their long-term fates
and collective impacts on ecosystem nitrogen use efficiency (NUE) and carbon (C) ...
Evolution
Machine learning holds great promise for classifying and identifying fossils, and
has recently been marshaled to identify trackmakers of dinosaur footprints and address
long-standing debates over whether some dinosaur tracks are the oldest birds or ...
When people collaborate in groups, they routinely face collective action problems:
for the group effort to succeed, individuals need to cooperate despite any incentives
to defect. These problems can be modeled with public goods games. To facilitate such
...
Lineages undergoing rapid evolutionary diversification may evolve a set of mixed traits
as a result of hybrid speciation, gene flow, or incomplete lineage sorting (ILS).
However, how best to quantify these alternative processes impacting phenotypic ...
Repeated games and stochastic games are important frameworks to study direct reciprocity.
Individuals react strategically to their coplayers’ previous behavior. While strategies
in such games can be arbitrarily complex, explorations of evolutionary ...
Immunology and Inflammation
CD4+ helper T cells are essential for controlling viral infections. During chronic LCMV
infection, CD4+ T cells differentiate into heterogeneous populations, including a TCF-1hi progenitor subset that serves as a reservoir to continuously replenish type 1 ...
The spatial organization of adaptive immune cells within lymph nodes is critical for
understanding immune responses during infection and disease. Here, we introduce AIR-SPACE,
an integrative approach that combines high-resolution spatial transcriptomics ...
In mammals, passive acquisition of maternal immunoglobulins is essential for neonatal
immune development and defense against infections. IgG, a central mediator of humoral
immunity, is maternally transferred via distinct mechanisms depending on placental
...
Natural killer (NK) cells may be engineered with chimeric antigen receptors (CARs)
to recognize tumor-associated antigens which bolsters their antitumor activity. More
so than CAR-T cells, CAR-NK cell responses result from an integration of signals from
a ...
Medical Sciences
Fe metal–organic framework–derived heterojunction for metabolic diagnosis of thymic epithelial tumor
Thymic epithelial tumors (TETs), rare yet clinically significant malignancies, face
diagnostic challenges due to their occult presentation and lack of noninvasive risk-stratification
tools, leading to systemic overtreatment and poor prognoses for high-...
Recent clinical trials have explored the combination of androgen receptor (AR) pathway
inhibitors and poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors as
a potential treatment for castration-resistant prostate cancer. This combination ...
Elexacaftor-tezacaftor-ivacaftor has transformed the treatment of people with cystic
fibrosis (CF) and the predominant cystic fibrosis transmembrane conductance regulator
(CFTR) variant F508del by delivering the faulty channel to the plasma membrane and ...
Diffuse large B cell lymphoma (DLBCL) is characterized by a variety of specific genetic
alterations that impact signaling pathway dependencies and therapeutic outcomes. Among
the recurrently mutated genes, we identified RHOA, a member of the small GTPase ...
Endometrial stromal sarcoma (ESS) is a rare uterine malignancy with limited treatment
options. We performed integrated whole-genome, whole-exome, and transcriptome sequencing
on 80 ESS tumors, comprising 32 low-grade (LG) and 48 high-grade (HG) tumors, to ...
Microbiology
Calcium oxalate stones comprise greater than 70% of all kidney stones. In the current
conceptual framework, the initial stone nidus is thought to include the aggregation
of inorganic crystallites, the formation of which is favored by elevated ...
The phage Mu C protein (MuC), along with core RNA polymerase (RNAP) and σ70, is required for transcription of phage late genes. We found that overexpression
of MuC was lethal in Escherichia coli and observed that host replication was overinitiating under ...
Type III secretion systems (T3SS) are critical virulence machines in many Gram-negative
bacteria, enabling hierarchical secretion of translocases followed by effectors. In
the Salmonella enterica serovar Typhimurium SPI-1 T3SS, the regulatory protein InvE ...
Emerging and reemerging viruses pose a significant threat to global health. Although
direct-acting antivirals have shown success, their efficacy is limited by the rapid
emergence of drug-resistant viral variants. Hence, there is an urgent need for ...
Neuroscience
Recent evidence indicates that even under stable environmental and behavioral conditions,
responses to sensory stimuli undergo continuous reformatting over the course of days,
a condition described as representational drift. However, the processes ...
Classic models associate goal-directed upper limb movements with cortical motor areas
and balance control with the brainstem. However, recent rodent studies suggest that
medullary regions and local spinal circuits also contribute to forelimb execution,
...
Understanding how animal behavior evolves remains a major challenge, with few studies
linking genetic changes to differences in neural function and behavior across species.
Here, we identify specific sensory adaptations associated with the emergence of ...
The molecular circadian clock is a ubiquitous transcriptional–translational feedback
loop that regulates CNS function, glial responses, and neurodegenerative pathology.
The nuclear receptors REV-ERB-α (Nr1d1) and REV-ERB-β (Nr1d2) are components of the ...
In the mammalian brainstem and spinal cord, glycine is the primary inhibitory neurotransmitter.
However, during development, many glycinergic neurons also corelease the inhibitory
neurotransmitter gamma-aminobutyric acid (GABA). Although the acute effects ...
The sense of smell has potent effects on appetite, but the underlying neural pathways
remain undefined. Here, we investigated how olfactory signals reach two subsets of
appetite-linked (“appetite”) neurons in the hypothalamic arcuate nucleus: Agouti-...
Physiology
In mammalian sperm, high HCO3− concentrations in semen and the oviduct activate soluble adenylyl cyclase (sAC),
which synthesizes cyclic AMP to regulate sperm motility. Here, we demonstrate that
sAC orthologs in echinoderms and fish, species whose sperm ...
Plant Biology
Canopy shade environments can negatively impact plant growth and survival. Phytochrome
A (phyA) is essential for seedling adaptation to deep shade, yet its role under moderate
natural canopy conditions remains unclear. By expressing a phyA-nanoLUC ...
Shaker potassium channels play essential roles in K+ uptake and distribution in plants. Studies on Shaker channels in Arabidopsis have provided a paradigmatic framework, but the rice genome encodes an additional
member, OsKAT1, whose function remians ...
Corrections
Cover image: Pictured is a golden snub-nosed monkey (Rhinopithecus roxellana), the northernmost Asian colobine primate. Yan-Qing Guo, Yiming Wang et al. analyzed trait evolution in two closely related colobine genera, Trachypithecus and Semnopithecus. The authors found that distinctive morphological similarities between the species Trachypithecus pileatus and Semnopithecus are the result of incomplete lineage sorting, which involves the independent retention of the same ancestral genotypes by different descendant species, rather than gene flow or hybrid speciation. The analysis suggests that incomplete lineage sorting may be more common in mammalian diversification than previously thought. See the article by Guo, Wang et al. e2524833123. Image credit: Yong Wang (photographer).
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