Molecular mechanism of dynein-dynactin complex assembly by LIS1

Science, Journal Year: 2024, Volume and Issue: 383(6690)

Published: March 28, 2024

Cytoplasmic dynein is a microtubule motor vital for cellular organization and division. It functions as ~4-megadalton complex containing its cofactor dynactin cargo-specific coiled-coil adaptor. However, how recognize diverse adaptors, they interact with each other during formation, the role of critical regulators such lissencephaly-1 (LIS1) protein remain unclear. In this study, we determined cryo–electron microscopy structure dynein-dynactin on microtubules LIS1 lysosomal adaptor JIP3. This reveals molecular basis interactions occurring activation. We show JIP3 activates despite atypical architecture. Unexpectedly, binds dynactin’s p150 subunit, tethering it along length dynein. Our data suggest that constrain to ensure efficient formation.

Language: Английский

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Axonal transport of autophagosomes is regulated by dynein activators JIP3/JIP4 and ARF/RAB GTPases

The Journal of Cell Biology, Journal Year: 2023, Volume and Issue: 222(12)

Published: Nov. 1, 2023

Neuronal autophagosomes form and engulf cargos at presynaptic sites in the axon are then transported to soma recycle their cargo. Autophagic vacuoles (AVs) mature en route via fusion with lysosomes become degradatively competent organelles; transport is driven by microtubule motor protein cytoplasmic dynein, activity regulated a sequential series of adaptors. Using lysate-based single-molecule motility assays live-cell imaging primary neurons, we show that JNK-interacting proteins 3 (JIP3) 4 (JIP4) activating adaptors for dynein on small GTPases ARF6 RAB10. GTP-bound promotes formation JIP3/4–dynein–dynactin complex. Either knockdown or overexpression RAB10 stalls transport, suggesting this GTPase also required coordinate opposing activities bound kinesin motors. These findings highlight complex coordination regulation during organelle neurons.

Language: Английский

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Regulatory imbalance between LRRK2 kinase, PPM1H phosphatase, and ARF6 GTPase disrupts the axonal transport of autophagosomes

Cell Reports, Journal Year: 2023, Volume and Issue: 42(5), P. 112448 - 112448

Published: May 1, 2023

Gain-of-function mutations in the LRRK2 gene cause Parkinson's disease (PD), increasing phosphorylation of RAB GTPases through hyperactive kinase activity. We find that LRRK2-hyperphosphorylated RABs disrupt axonal transport autophagosomes by perturbing coordinated regulation cytoplasmic dynein and kinesin. In iPSC-derived human neurons, knockin strongly LRRK2-p.R1441H mutation causes striking impairments autophagosome transport, inducing frequent directional reversals pauses. Knockout opposing protein phosphatase 1H (PPM1H) phenocopies effect LRRK2. Overexpression ADP-ribosylation factor 6 (ARF6), a GTPase acts as switch for selective activation or kinesin, attenuates defects both p.R1441H PPM1H knockout neurons. Together, these findings support model where regulatory imbalance between ARF6 induces an unproductive "tug-of-war" disrupting processive transport. This disruption may contribute to PD pathogenesis impairing essential homeostatic functions autophagy.

Language: Английский

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DENND6A links Arl8b to a Rab34/RILP/dynein complex, regulating lysosomal positioning and autophagy

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Jan. 31, 2024

Lysosomes help maintain cellular proteostasis, and defects in lysosomal positioning function can cause disease, including neurodegenerative disorders. The spatiotemporal distribution of lysosomes is regulated by small GTPases Rabs, which are activated guanine nucleotide exchange factors (GEFs). DENN domain proteins the largest family Rab GEFs. Using a cell-based assay, we screened DENND6A, member protein against all known Rabs identified it as potential GEF for 20 Rab34. Here, demonstrate that DENND6A activates Rab34, recruits RILP/dynein complex to lysosomes, promoting lysosome retrograde transport. Further, identify an effector Arl8b, major regulatory GTPase on lysosomes. We Arl8b peripheral activate Rab34 initiate transport, regulating nutrient-dependent juxtanuclear repositioning. Loss impairs autophagic flux. Our findings support model whereby Arl8b/DENND6A/Rab34-dependent trafficking controls autophagy.

Language: Английский

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Disruptions in axonal lysosome transport and its contribution to neurological disease

Current Opinion in Cell Biology, Journal Year: 2024, Volume and Issue: 89, P. 102382 - 102382

Published: June 20, 2024

Lysosomes are central to the maintenance of protein and organelle homeostasis in cells. Optimal lysosome function is particularly critical for neurons which long-lived, non-dividing highly polarized with specialized compartments such as axons dendrites distinct architecture, cargo, turnover requirements. In recent years, there has been a growing appreciation role played by axonal transport regulating neuronal development, its functioning. Perturbations optimal abundance leading either strong accumulations or dearth lysosomes both linked altered health this review we highlight how two regulators abundance, small GTPase Arl8 adaptor JIP3, aid maintaining alterations their levels activity could contribute neurodevelopmental neurodegenerative diseases.

Language: Английский

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Proteome of axon transport

Elsevier eBooks, Journal Year: 2025, Volume and Issue: unknown, P. 181 - 199

Published: Jan. 1, 2025

Language: Английский

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The Huntingtin Transport Complex

Biochemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

A dynamic network of scaffolding molecules, adaptor proteins, and motor proteins work together to orchestrate the movement mRNA, vesicular cargoes. Defects in intracellular transport can often lead neurodegeneration. Huntingtin (HTT) is a ubiquitously expressed protein with multitude cellular roles, including regulating various organelles. HTT remarkable its ability regulate wide range cargoes, BDNF vesicles, APP early endosomes, autophagosomes, lysosomes, mitochondria. This interaction allows huntingtin control microtubule-based by kinesin dynein, as well actin-based myosin VI. By forming complexes multiple adaptors, regulates variety cargoes guides through different stages biosynthesis, signaling, degradation. Accordingly, pathogenic polyglutamine expansions seen Huntington's Disease (HD) dysregulate complexes, resulting defects

Language: Английский

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Anti-Parkinsonian Drugs Rescue Locomotor Deficits in JIP3 Knockout Zebrafish: Implications for Treating Patients with MAPK8IP3-related Neurodevelopmental Disorders

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 6, 2025

ABSTRACT MAPK8IP3- related neurodevelopmental disorders are a spectrum of rare conditions caused by de novo mutations in the MAPK8IP3 gene that encodes JIP3 protein. These associated with symptoms manifest children and cause brain abnormalities, profound intellectual disabilities, movement disorders, developmental delays. is required for axonal transport proteins organelles between soma synaptic terminal neurons, process critical normal development function. Homozygous loss-of-function lead to impaired aggregation cargo, which result swelling stunted elongation. Despite these severe outcomes, disease mechanisms poorly understood, no current treatments available. Here we conduct thorough morphological, behavioral, motility phenotyping knockout zebrafish identify locomotor deficits morphological abnormalities. To treatment options, used insights from expert clinicians artificial intelligence tool, mediKanren, drug candidates hypothesized improve patient or compensate loss at molecular level. We then prioritized drugs FDA-approved, safe children, readily collective efforts identified amantadine levodopa as candidate therapies rescued motor phenotypes zebrafish.

Language: Английский

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

Life Science Alliance, Journal Year: 2025, Volume and Issue: 8(5), P. e202402934 - e202402934

Published: Feb. 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 .

Language: Английский

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TBCK-deficiency leads to compartment-specific mRNA and lysosomal trafficking defects in patient-derived neurons

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: March 7, 2025

ABSTRACT Monogenic pediatric neurodegenerative disorders can reveal fundamental cellular mechanisms that underlie selective neuronal vulnerability. TBCK-Encephaloneuronopathy (TBCKE) is a rare autosomal recessive disorder caused by stop-gain variants in the TBCK gene. Clinically, patients show evidence of profound neurodevelopmental delays, but also symptoms progressive encephalopathy and motor neuron disease. Yet, physiological role protein remains unclear. We report human TBCKE model, derived from iPSCs homozygous for Boricua variant (p.R126X). Using unbiased proteomic analyses neurons, we find interacts with PPP1R21, C12orf4, Cryzl1, consistent being part FERRY mRNA transport complex. Loss leads to depletion C12ORF4 levels across multiple cell types, suggesting may play regulating at least some members preferentially, not exclusively, localizes surface endolysosomal vesicles colocalize lysosomes. Furthermore, TBCK-deficient neurons have reduced content axonal compartment relative soma. lysosomal dynein/dynactin adapter JIP4, which functionally exhibiting striking retrograde trafficking defects. Hence, our work reveals mediate mRNA, particularly along lysosomes compartments. TBCK-deficiency compartment-specific defects likely contribute preferential susceptibility neurodegeneration.

Language: Английский

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