Fat traffic control: S-acylation in axonal transport

Molecular Pharmacology, Год журнала: 2025, Номер 107(6), С. 100039 - 100039

Опубликована: Апрель 17, 2025

Neuronal axons serve as a conduit for the coordinated transport of essential molecular cargo between structurally and functionally distinct subcellular compartments via axonal machinery. Long-distance, efficient membrane-bound organelles enables signal transduction neuronal homeostasis. Efficient is conducted by dynein kinesin ATPase motors that use local ATP supply from metabolic enzymes tethered to vesicles. Molecular motor adaptor proteins promote processive motility selectivity fast transport. Axonal impairments are directly causative or associated with many neurodegenerative diseases neuropathologies. Cargo specificity, cargo-adaptor proteins, posttranslational modifications cargo, microtubules, protein subunits all contribute precise regulation vesicular transit. One lipid modification particularly important in neurons regulating trafficking, protein-protein interactions, association membranes S-acylation. Interestingly, cargos, cytoskeletal-associated subunits, adaptors S-acylated modulate Here, we review established regulatory role S-acylation provide evidence broader motor-cargo complex machinery, low-throughput studies S-acyl-proteomic data sets. We propose regulates through localization required motile cargo-complex machinery relate how perturbed contributes neurological disorders. SIGNIFICANCE STATEMENT: This investigates its connection diseases, focus on emerging connections motors, make up trafficking

Язык: Английский

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Single-molecule imaging of stochastic interactions that drive dynein activation and cargo movement in cells

The Journal of Cell Biology, Год журнала: 2024, Номер 223(3)

Опубликована: Янв. 19, 2024

Cytoplasmic dynein 1 (dynein) is the primary minus end–directed motor protein in most eukaryotic cells. Dynein remains an inactive conformation until formation of a tripartite complex comprising dynein, its regulator dynactin, and cargo adaptor. How this process activation occurs unclear since it entails three-protein inside crowded environs cell. Here, we employed live-cell, single-molecule imaging to visualize track fluorescently tagged dynein. First, observed that only ∼30% molecules bound microtubule (MT) engaged movement, too for short duration ∼0.6 s. Next, using high-resolution live fixed cells correlative light electron microscopy, discovered dynactin endosomal remained proximity each other MTs. We then two-color movement effected by single binding. Finally, performed long-term show movements are sufficient drive perinuclear region Taken together, search mechanism facilitated dynein’s frequent MT binding–unbinding kinetics: (i) futile event when does not encounter anchored MT, dissociates diffuses into cytoplasm, (ii) encounters upon binding, moves run. Several these runs undertaken succession long-range directed movement. In conclusion, demonstrate capture coupled step relies on reduction dimensionality enable transport cellulo behavior emerges from stochastic motor–cargo interactions.

Язык: Английский

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Vimentin undergoes liquid–liquid phase separation to form droplets which wet and stabilize actin fibers

Proceedings of the National Academy of Sciences, Год журнала: 2025, Номер 122(10)

Опубликована: Март 3, 2025

The cytoskeleton is composed of F-actin, microtubules, and intermediate filaments (IFs). Vimentin one the most ubiquitous well-studied IFs. It involved in many activities including wound healing, tissue fibrosis, cancer metastasis, all which require rapid vimentin IF assembly. In this paper, we report that forms liquid condensates appear to enable filament growth. Given transient nature these droplets, focus on properties vimentin-Y117L, has a point mutation leads formation but not IFs, enabling us study droplets detail. dissolve under 1,6-Hexanediol treatment decreasing concentration, confirming they are liquid, phase separated. These extensively wet actin stress fibers, rendering them resistant actin-binding drugs protecting from depolymerization. We show similar behavior occurs wild-type during its assembly into filaments.

Язык: Английский

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MINFLUX reveals dynein stepping in live neurons

Proceedings of the National Academy of Sciences, Год журнала: 2024, Номер 121(38)

Опубликована: Сен. 10, 2024

Dynein is the primary molecular motor responsible for retrograde intracellular transport of a variety cargoes, performing successive nanometer-sized steps within milliseconds. Due to limited spatiotemporal precision established methods tracking, current knowledge dynein stepping essentially slowed-down measurements in vitro. Here, we use MINFLUX fluorophore localization directly track CRISPR/Cas9-tagged endogenous with nanometer/millisecond living neurons. We show that primarily takes 8 nm steps, including frequent sideways but few backward steps. Strikingly, majority direction reversals between and anterograde movement occurred on time scale single (16 ms), suggesting rapid regulatory reversal mechanism. Tug-of-war-like behavior during pauses or was unexpectedly rare. By analyzing dwell concluded rate-limiting process underlies mechanism, likely arising from just one adenosine 5′-triphosphate hydrolysis event being required each step. Our study underscores power elucidate changes underlying protein function cells.

Язык: Английский

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Axonal transport of CHMP2b is regulated by kinesin-binding protein and disrupted by CHMP2b^intron5

Life Science Alliance, Год журнала: 2025, Номер 8(5), С. e202402934 - e202402934

Опубликована: Фев. 28, 2025

CHMP2b is a core component of the ESCRT pathway that catalyzes formation multivesicular bodies for endolysosomal protein degradation. Although mutation/loss-of-function promotes presynaptic dysfunction and degeneration, indicating its critical role in homeostasis, mechanisms responsible localization recruitment to synapses remain unclear. Here, we characterize axonal trafficking show transport boutons, as well cotransport with other proteins, are regulated by neuronal activity. In contrast, frontotemporal dementia–causative intron5 mutation exhibits little processive movement or presence absence Instead, vesicles exhibit oscillatory behavior reminiscent tug-of-war between kinesin dynein motor proteins. We this phenotype caused deficient binding kinesin-binding protein, which identify key regulator transport. These findings shed light on synaptic localization, their disruption .

Язык: Английский

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Engineered Chitosan‐Derived Nanocarrier for Efficient siRNA Delivery to Peripheral and Central Neurons

Advanced Healthcare Materials, Год журнала: 2025, Номер unknown

Опубликована: Май 13, 2025

Abstract Gene therapy using small interfering RNA (siRNA) holds promise for treating neurological disorders by silencing specific genes, like the phosphatase and tensin homolog ( PTEN ) gene, which restricts axonal growth. Effective siRNA delivery to neurons, however, poses challenges due premature nucleic acid degradation unspecific delivery. Chitosan‐based systems, noted their biocompatibility, face limitations such as low transfection efficiency lack of neurotropism. Building on previous successes with neuron‐targeted DNA chitosan, a novel approach aimed at downregulation is proposed. This involves thiolated trimethyl chitosan (TMCSH)–based nanoparticles functionalized neurotropic C‐terminal fragment tetanus neurotoxin heavy chain (HC) efficient peripheral central neurons. These polyplexes demonstrate suitable physicochemical properties, no adverse effects neuronal electrophysiology. Diverse models, including 3D ex vivo cultures microfluidics, confirm polyplexes’ neurospecificity. HC‐functionalization significantly enhances binding, live cell imaging reveals fivefold faster retrograde transport along axons. Furthermore, targeting promoted outgrowth in embryonic cortical In conclusion, proposed represent promising platform delivery, offering potential clinical translation therapeutic applications.

Язык: Английский

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Multiple steps of dynein activation by Lis1 visualized by cryo-EM

Nature Structural & Molecular Biology, Год журнала: 2025, Номер unknown

Опубликована: Май 23, 2025

Abstract Cytoplasmic dynein-1 (dynein) is an essential molecular motor controlled in part by autoinhibition. Lis1, a key dynein regulator mutated the neurodevelopmental disease lissencephaly, plays role activation. We recently identified structure of partially autoinhibited bound to which suggests intermediate state dynein’s activation pathway. However, other structural information needed fully understand how Lis1 activates dynein. Here, we used cryo-EM and yeast incubated with ATP at different time points reveal conformations that propose represent additional states solved 16 high-resolution structures, including 7 distinct dynein–Lis1 structures from same sample. Our data support model relieves autoinhibition increasing its basal hydrolysis rate promoting compatible complex assembly motility. Together, this analysis advances our understanding contribution process.

Язык: Английский

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Cargo specificity, regulation, and therapeutic potential of cytoplasmic dynein

Experimental & Molecular Medicine, Год журнала: 2024, Номер 56(4), С. 827 - 835

Опубликована: Апрель 1, 2024

Intracellular retrograde transport in eukaryotic cells relies exclusively on the molecular motor cytoplasmic dynein 1. Unlike its counterpart, kinesin, has a single isoform, which raises questions about cargo specificity and regulatory mechanisms. The precision of dynein-mediated is governed by multitude factors, including temperature, phosphorylation, microtubule track, interactions with family activating adaptor proteins. Activating adaptors are particular importance because they not only activate unidirectional motility but also connect diverse array cargoes motor. Therefore, it unsurprising that dysregulation dynein-activating machinery can lead to diseases such as spinal muscular atrophy, lower extremity, dominant. Here, we discuss within vitro, present several methodologies employed track motion We highlight newly identified their roles regulating dynein. Finally, explore potential therapeutic applications manipulating address linked malfunction.

Язык: Английский

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MINFLUX Reveals Dynein Stepping in Live Neurons

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Май 23, 2024

Dynein is the primary molecular motor responsible for retrograde intracellular transport of a variety cargoes, performing successive nanometer-sized steps within milliseconds. Due to limited spatiotemporal precision established methods tracking, current knowledge dynein stepping essentially slowed-down measurements in vitro. Here, we use MINFLUX fluorophore localization directly track CRISPR/Cas9-tagged endogenous with nanometer/millisecond living neurons. We show that primarily takes 8 nm steps, including frequent sideways but few backward steps. Strikingly, majority direction reversals between and anterograde movement occurred on time scale single (16 ms), suggesting rapid regulatory reversal mechanism. Tug-of-war-like behavior during pauses or was unexpectedly rare. By analyzing dwell concluded rate-limiting process underlies mechanism whereby consumes one adenosine 5’-triphosphate (ATP) per step. Our study underscores power elucidate changes underlying protein function cells.

Язык: Английский

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Episodic Transport of Protein Aggregates Achieves a Positive Size Selectivity in Aggresome Formation

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Авг. 7, 2024

Eukaryotic cells direct toxic misfolded proteins to various protein quality control pathways based on their chemical features and aggregation status. Aggregated are targeted selective autophagy or specifically sequestered into the "aggresome," a perinuclear inclusion at microtubule-organizing center (MTOC). However, mechanism for selectively sequestering aggregates aggresome remains unclear. To investigate formation, we reconstituted MTOC-directed aggregate transport in

Язык: Английский

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