ACS Publications最新文献

The cytoskeleton is a dynamic intracellular network that governs cell shape, migration, division, and mechanotransduction. Precise spatiotemporal control of cytoskeletal regulation is essential for understanding how these processes are coordinated in physiology and disease, yet conventional pharmacological and genetic approaches often lack sufficient resolution or reversibility. Optogenetic technologies provide a powerful alternative by enabling light-controlled, noninvasive manipulation of cytoskeletal regulators with high temporal precision and subcellular specificity. This review summarizes recent advances in genetically encoded optogenetic tools for interrogating cytoskeletal dynamics. We discuss core design strategies, including allosteric regulation, light-induced oligomerization, heterodimerization, and dissociation, and highlight representative applications targeting actin filaments, microtubules, and upstream signaling pathways such as Rho family GTPases. We conclude by outlining current limitations and emerging directions, including improved tissue penetration, reduced phototoxicity, and multiplexed optical control, which are expected to further expand the utility of optogenetics in cytoskeleton research.

Computational modeling of heterodimers of mono- and diradical molecules with C₆₀^- indicates that scanning probe microscopy could characterize multicenter covalent-like interactions, also known as pancake bonds, on surfaces. By functionalizing the SPM tip with C₆₀ and creating its monoanionic state by applying the corresponding voltage, individual pancake-bonded heterodimers with various radical molecules can be formed and characterized. All three proposed radical/diradical molecules readily form pancake-bonded dimers with C₆₀^-, and their structural and energetic minima are easily discernible from the dispersion-bonded van der Waals heterodimers with C₆₀. Two of the three newly designed heterodimers show intermolecular C···C distances that are shorter than the current shortest pancake bond. This exploratory work aims to stimulate new studies on the interactions of radical molecules by the use of SPM techniques.

The use of mRNA therapies has innovated the clinical progress of cancer immunotherapy. However, current immunotherapeutic approaches are unable to achieve site- or immune-cell-specific delivery, resulting in adverse immune responses in off-target tissues. In addition, the commercial lipid nanoparticle (LNP) formulations with a poly(ethylene glycol) coating generally undergo significant hepatic accumulation during clearance. To promote site- and immune-cell-specific delivery of therapeutic mRNA-LNPs, we investigated several bioconjugation approaches to attach targeting antibodies onto the surface of polymer-functionalized mRNA-LNPs. Building on our previous work, side-chain sulfoxide polymer-lipid conjugate PMSEA-DSPE was used to incorporate a low-fouling polymeric LNP coating. trans-Cyclooctene functionality was incorporated within PMSEA-DSPE end groups to allow conjugation to the tetrazine-functionalized nanobody 9G8 for EGFR targeting. Bioconjugation methods were compared, including direct conjugation and post-insertion. The results showed that 9G8-attached PMSEA mRNA-LNPs prepared via direct conjugation significantly enhanced cell association and in vitro transfection efficiency with an EGFR-positive cell line, demonstrating the potency of active targeting for mRNA-LNP platforms with side-chain polymer coatings.

Grease is an organogel consisting of low molecular mass gelators that exhibit self-assembly. We performed all-atom molecular dynamics simulations of two types of lithium soaps, lithium stearate (LiS) and lithium 12-hydroxystearate (Li12HS), in hexane as a solvent to investigate the aggregation process. We found that the hydroxy group, present in Li12HS but absent in LiS, significantly affects the aggregation process. LiS forms plate-like reverse micelles with a cluster of the head groups inside and the tail chains oriented outward, a structure that is qualitatively consistent with previous experimental results. At room temperature, Li12HS also forms small reverse micelles, but these micelles are interconnected by their tails, whose hydroxy side chains form bonds with the head group clusters, leading to the formation of a (meta)stable network structure. Analyzing the types of bonds involving the hydroxy groups based on their bonding partners, we found that most types hinder the transition from the network structure to an experimentally observed crystal-like structure, while bonds between hydroxy groups contribute to this crystal-like structure. At high temperatures, the number of these bonds decreases significantly, which allows the aggregates to undergo structural fluctuations and to adopt various conformations without being trapped in metastable states. This temperature effect, as demonstrated by our simulation involving initial heating followed by cooling to room temperature, promotes the transition from a network structure to a crystal-like structure. Our findings provide molecular-level insights into the initial aggregation dynamics of lithium soaps and into the mechanisms through which thermal cycling alters aggregation pathways and final structures.

Phenothiazine-based donor-acceptor (D-A) molecules represent an important class of luminogens owing to their butterfly shaped geometry and rich excited-state behavior. Sulfur oxidation of the phenothiazine core has been widely employed as an effective strategy to tune their photophysical properties; however, the generality of this approach across different donor frameworks remains unclear. Herein, we report a systematic comparative study on the interplay between donor identity and sulfur oxidation in regulating the photophysics of phenothiazine-based D-A molecules. A carbazole-based molecular series with stepwise sulfur oxidation (CZ-S, CZ-SO, and CZ-SOO) was designed as a direct analogue of a previously reported diphenylamine-based system, enabling an unambiguous evaluation of donor-dependent effects under identical structural and oxidation conditions. Comprehensive photophysical investigations reveal that replacing diphenylamine with the more rigid carbazole donor fundamentally reshapes the impact of sulfur oxidation on emission behavior. In solution, carbazole-based derivatives exhibit attenuated solvatochromism and moderated intramolecular charge transfer (ICT), as confirmed by Lippert-Mataga analysis. In the aggregated and solid states, the carbazole system displays diversified emission behaviors, including aggregation-induced emission (AIE), aggregation-induced emission enhancement (AIEE), aggregation-caused quenching (ACQ), nonmonotonic solid-state emission shifts, and distinct mechanochromic mechanisms. Single-crystal X-ray diffraction analysis demonstrates that these donor-dependent photophysical differences originate primarily from enhanced conformational rigidity and restricted packing adaptability introduced by the carbazole donor, rather than from changes in intermolecular interaction motifs. This work establishes that sulfur oxidation alone does not universally dictate photophysical outcomes in phenothiazine-based systems; instead, donor identity plays a decisive and cooperative role. These findings provide new insights into the rational design of butterfly shaped luminogens with programmable photophysical responses.

Polymerization-induced self-assembly (PISA) is a versatile synthetic method that integrates polymerization and molecular self-assembly in a single step. It essentially relies on the decreasing solubility of polymers as their chain lengths increases during polymerization, a change that drives the spontaneous formation of nanoscale assembled structures via intermolecular interactions, thereby offering distinct advantages of operational simplicity, high efficiency, and controllable nanostructure morphology. To expand the range of achievable aggregate morphologies and clarify the underlying mechanisms from a kinetic perspective, this study proposes an in silico research to investigate the regulatory mechanisms of binary mixed solvents in PISA systems. The results show that incorporating a second solvent with an affinity for solvophobic blocks induces the formation of large interconnected micelles. This phenomenon arises because the second solvent preferentially accumulates near the core of the aggregate formed by the solvophobic blocks, causing slight dissolution of the core and further promoting the extension and fusion of micelles. Additionally, as the monomer feed ratio and polymer molecular weight increase, these micelles undergo further fusion to form hollow vesicular structures, which is further confirmed by experimental observations. This study not only enriches the diversity of aggregate morphologies obtained via PISA but also provides new insights into the morphological control mechanisms of mixed solvent systems.

Gap junction channels, formed by the docking of two hemichannels from adjacent cells, are essential for intercellular communication. Connexin-43 (Cx43), the most widely expressed connexin, is critically involved in numerous physiological processes. Phosphorylation of Cx43 is a key regulatory mechanism that influences all aspects of its function, including trafficking, channel gating, and permeability. Here, we report a full-length computational model of the dodecameric Cx43 gap junction channel in double bilayers, including its intracellular loops and cytoplasmic regulatory C-terminal domains (CTDs). Furthermore, we performed all-atom molecular dynamics simulations of four systems representing different phosphorylation states. Our results demonstrate that increased phosphorylation of serine residues in the CTD induces more extended and flexible CTD conformations with greater solvent exposure, meanwhile narrowing the channel pore. Distinct gating states are closely associated with hydrophobic interactions between the N-terminal helices (NTHs) and transmembrane domain 2 (TM2). Unfolding of the NTHs disrupts the interactions, leading to pore distortion and a transition from the initial closed state to a more open conformation. These findings provide novel insights into the structural dynamics and regulatory mechanisms of the Cx43 gap junction channels.

Amaryllidaceae alkaloids (AAs) are a valuable class of plant specialized metabolites with diverse pharmacological properties. However, the discovery of enzymes involved in AA biosynthesis through traditional methods has been subjected to several drawbacks over time, demanding labor-intensive screening and optimized growth conditions. Here, we introduce a Support Vector Machine (SVM)-algorithm-based approach that overcomes these challenges by predicting enzyme-substrate interactions based solely on amino acid sequences and molecular fingerprints. We employed a training set of 90 enzyme sequences, equally balanced, where the positive enzymes were selected based on chemical similarity to the substrate of interest (4'-O-methylnorbelladine (4OMET)), and the negative enzymes corresponded to active enzymes toward 4OMET-decoy molecules. Applying this prediction model to transcriptomic data of Crinum asiaticum bulbs identified 19 putative cytochrome P450 enzymes. Functional assays in heterologous systems showed that five candidates reproducibly depleted 4OMET, including a CYP81-like candidate - a P450 class not previously linked to 4OMET turnover. Overall, this strategy bypasses the need for stringent alkaloid accumulation conditions and precise tissue sampling for enzyme discovery, offering a scalable and cost-effective candidate selection alternative for downstream biochemical characterization and pathway elucidation efforts.