UNVEILING CANCER-RELATED METAPLASTIC CELLS IN BOTH HELICOBACTER PYLORI INFECTION AND AUTOIMMUNE GASTRITIS.

BACKGROUND AND AIMS: Gastric metaplasia may arise as a consequence of chronic inflammation and is associated with an increased risk of gastric cancer development. While Helicobacter pylori (Hp) infection and autoimmune gastritis (AIG) both induce gastric metaplasia, possible distinctions in resulting metaplastic cells and their respective cancer risks requires further investigation. METHODS: Employing both mouse models and human subjects, we scrutinized the metaplasia originating from Hp infection and AIG. Gastric pathology and metaplasia were examined through histopathologic assessment. Molecular features of metaplastic cells were defined using single-cell transcriptomics in murine models of Hp infection and AIG, as well as in human biopsies from patients with Hp infection and AIG. Expression of a newly defined cancer-related metaplastic biomarker was confirmed through immunofluorescence. RESULTS: Metaplasia in Hp infection and AIG displayed comparable histopathological and transcriptional features. Diverse metaplastic subtypes were identified across both disease settings, with subtle differences in the prevalence of certain subtypes between inflammatory contexts. Notably, Hp infection did not drive a unique metaplastic cell phenotype. One metaplastic subtype, which resembled incomplete intestinal metaplasia and shared transcriptional features with gastric cancer was identified in both diseases. This cancer-like metaplastic subtype was characterized by expression of the cancer-associated biomarker ANPEP/CD13. CONCLUSION: Both Hp infection and AIG trigger a diverse array of metaplastic cell types. Identification of a cancer-related metaplastic cell uniquely expressing ANPEP/CD13, present in both Hp- and AIG-induced gastritis, indicates the carcinogenic capacity of both diseases. This discovery can guide early detection and risk stratification for patients with chronic gastritis.

Antifreeze protein type I in the vitrification solution improves the cryopreservation of immature cat oocytes.

Oocyte cryopreservation is not yet considered a reliable technique since it can reduce the quality and survival of oocytes in several species. This study determined the effect of different concentrations of antifreeze protein I (AFP I) on the vitrification solution of immature cat oocytes. For this, oocytes were randomly distributed in three groups and vitrified with 0 µg/mL (G0, 0 µM); 0.5 µg/mL (G0.5, 0.15 µM), or 1 µg/mL (G1, 0.3 µM) of AFP I. After thawing, oocytes were evaluated for morphological quality, and compared to a fresh group (FG) regarding actin integrity, mitochondrial activity and mass, reactive oxygen species (ROS) and glutathione (GSH) levels, nuclear maturation, expression of GDF9, BMP15, ZAR-1, PRDX1, SIRT1, and SIRT3 genes (normalized by ACTB and YWHAZ genes), and ultrastructure. G0.5 and G1 presented a higher proportion of COCs graded as I and while G0 had a significantly lower quality. G1 had a higher percentage of intact actin in COCs than G0 and G0.5 (P < 0.05). There was no difference (P > 0.05) in the mitochondrial activity between FG and G1 and they were both higher (P < 0.05) than G0 and G0.5. G1 had a significantly lower (P < 0.05) mitochondrial mass than FG and G0, and there was no difference among FG, G0, and G0.5. G1 had higher ROS than all groups (P < 0.05), and there was no difference in GSH levels among the vitrified groups (P > 0.05). For nuclear maturation, there was no difference between G1 and G0.5 (P > 0.05), but these were both higher (P < 0.05) than G0 and lower (P < 0.05) compared to FG. Regarding gene expression, in G0 and G0.5, most genes were downregulated compared to FG, except for SIRT1 and SIRT3 in G0 and SIRT3 in G0.5. In addition, G1 kept the expression more similar to FG. Regardless of concentration, AFP I supplementation in vitrification solution of immature cat oocytes improved maturation rates, morphological quality, and actin integrity and did not impact GSH levels. In the highest concentration tested (1 µg/mL), AFP maintained the mitochondrial activity, reduced mitochondrial mass, increased ROS levels, and had the gene expression more similar to FG. Altogether these data show that AFP supplementation during vitrification seems to mitigate some of the negative impact of cryopreservation improving the integrity and cryosurvival of cat oocytes.

KAT2A and KAT2B prevent double-stranded RNA accumulation and interferon signaling to maintain intestinal stem cell renewal.

Histone acetyltransferases KAT2A and KAT2B are paralogs highly expressed in the intestinal epithelium, but their functions are not well understood. In this study, double knockout of murine Kat2 genes in the intestinal epithelium was lethal, resulting in robust activation of interferon signaling and interferon-associated phenotypes including the loss of intestinal stem cells. Use of pharmacological agents and sterile organoid cultures indicated a cell-intrinsic double-stranded RNA trigger for interferon signaling. Acetyl-proteomics and sequencing of immunoprecipitated double-stranded RNA were used to interrogate the mechanism behind this response, which identified mitochondria-encoded double-stranded RNA as the source of intrinsic interferon signaling. Kat2a and Kat2b therefore play an essential role in regulating mitochondrial functions and maintaining intestinal health.

Thiazine-derived compounds in inhibiting efflux pump in Staphylococcus aureus K2068, mepA gene expression, and membrane permeability alteration.

Staphylococcus aureus is a bacterium responsible for resistance to multiple drugs and the efflux system is widely studied among the resistance mechanisms developed by this species. The present study evaluates the inhibition of the MepA efflux pump by thiadiazine-derived compounds. For this purpose, thiadiazine-derived compounds (IJ-14 to IJ-20) were tested against S. aureus K2068 strains. Microdilution tests were initially conducted to assess the Minimum Inhibitory Concentration (MIC) of the compounds and their efflux pump inhibition activity. In addition, fluorimetry tests were performed using BrEt emission and tests were conducted to inhibit the expression of the mepA gene. This involved comparing the bacterial gene expression with the antibiotic alone to the gene expression after combining compounds (IJ-17 and IJ-20) with the antibiotic. Furthermore, membrane permeability assessment tests and in silico molecular docking tests were performed. It was observed that the IJ17 and IJ20 compounds exhibited direct activity against the tested strain. The IJ17 compound produced significant results in the gene inhibition tests, which was also evidenced through the membrane permeability alteration test. These findings suggest that thiadiazine-derived compounds have promising effects against one of the main resistance mechanisms, with the IJ17 compound presenting observable mechanisms of action.

Neonicotinoid Residues on Filter Paper Lack Insecticidal Activity.

Neonicotinoid insecticides are used against agricultural, forest, and urban insect pests. Evaluation of dry neonicotinoid residues on treated filter paper is a commonly used method to determine the toxicity of active ingredients towards target and non-target organisms. Dry residues of four neonicotinoids, acetamiprid, dinotefuran, imidacloprid, and thiamethoxam, on filter paper did not cause significant levels of mortality in Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae) and Nezara viridula (L.) (Hemiptera: Pentatomidae) when compared to paired untreated groups. Conversely, nearly 100% mortality was observed when test insects were exposed to dry neonicotinoid residues on leaf discs and glass plate surfaces. On the other hand, dry residues of the pyrethroid bifenthrin on filter paper, leaf disks, and glass plates killed significantly more test insects when compared to untreated groups. Additional bioassays tested the toxicity of acetamiprid and thiamethoxam by evaluating the toxicity of dry residues on (1) the upper and (2) lower surfaces of treated filter paper, (3) on a glass plate underneath treated filter paper, (4) on the upper surface of treated filter paper treated with insecticide and adjuvant, and (5) dried residues on a glass plate after dipping treated filter paper in water and letting the solvent dry on the inert test surface. The results indicated that neonicotinoid insecticides applied to filter paper were adsorbed. Toxic compounds possibly move in between and binding to paper fibers so that no toxic residues were left on treated surfaces. However, adsorbed insecticides were still biologically active when washed out of filter paper and dried on an inert glass surface. The results reported here clearly demonstrate that the toxicity of neonicotinoid insecticides should not be evaluated using filter paper as a test surface.

Optimising Bioprinting Nozzles through Computational Modelling and Design of Experiments.

3D bioprinting is a promising technique for creating artificial tissues and organs. One of the main challenges of bioprinting is cell damage, due to high pressures and tensions. During the biofabrication process, extrusion bioprinting usually results in low cell viability, typically ranging from 40% to 80%, although better printing performance with higher cell viability can be achieved by optimising the experimental design and operating conditions, with nozzle geometry being a key factor. This article presents a review of studies that have used computational fluid dynamics (CFD) to optimise nozzle geometry. They show that the optimal ranges for diameter and length are 0.2 mm to 1 mm and 8 mm to 10 mm, respectively. In addition, it is recommended that the nozzle should have an internal angle of 20 to 30 degrees, an internal coating of ethylenediaminetetraacetic acid (EDTA), and a shear stress of less than 10 kPa. In addition, a design of experiments technique to obtain an optimal 3D bioprinting configuration for a bioink is also presented. This experimental design would identify bioprinting conditions that minimise cell damage and improve the viability of the printed cells.

Performance, nutrient utilization and meat quality traits in Bos indicus cattle: a meta-analysis examining the effect of residual feed intake.

This meta-analysis aims to investigate the effects of residual feed intake (RFI) phenotype on performance, nutrient utilization and meat quality traits in Zebu (Bos indicus) cattle. Twenty-three peer-reviewed publications with 37 treatment means were included in the dataset. Weighted mean difference analysis compared animals categorized into low RFI (more efficient) versus medium or high RFI (less efficient) groups. Data heterogeneity via meta-regression and subgroup analysis, considering variables such as animal age, sex class, experimental duration, RFI group, dietary concentrate, and estimated metabolizable energy intake were also explored. The predominant genetic group of cattle in the dataset was Nellore (89.18%), followed by Brahman (10.81%). More efficient animals (low RFI phenotype) exhibited less dry matter intake (DMI; P < 0.010) than medium or high RFI animals (-0.95 kg vs. -0.42 kg/d). Cattle dietary crude protein and fiber digestibility were consistent across RFI groups (P > 0.05), while dietary ether extract digestibility tended to decrease (P = 0.050) in low RFI animals (-13.20 g/kg DM). Low RFI animals tended to increased (P = 0.065) ribeye area (REA) compared to the high/medium RFI groups, while carcass backfat thickness (BFT) decreased (P = 0.042) compared to high/medium RFI groups. Moreover, there was an increase (P < 0.001) of 0.22 kg in Warner-Bratzler shear force (WBSF) and a reduction (P < 0.001) in the myofibrillar fragmentation index (MFI) in low RFI animals. Meat color parameters (lightness [L*] and yellowness [b*]) and visual marbling scores were consistent (P > 0.05) across RFI groups. In conclusion, Zebu cattle classified as efficient (low RFI) exhibited reduced DMI, which improves their feed efficiency. However, BFT and meat quality parameters such as tenderness (WBSF and MFI) and redness [a*] were compromised by low RFI phenotype, highlighting the challenge of enhancing feed efficiency and meat quality traits in Zebu cattle.

Sources of PM10 ionic species in the South-West Mediterranean (Algeria).

The contents of water-soluble major's ions (MSA, Cl-, NO3-, SO42-, Na+, NH4+, K+, Mg2+, and Ca2+) in the PM10 particle fraction were investigated thanks to detailed measurements of the main chemical constituents of PM10 in remote coastal areas in Bou-Ismail; in the South-West of the Mediterranean Sea (Algeria), during a 2-year period; from July 2011 to August 2013, under the framework of the ChArMEx project (Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr ). The total water-soluble ion concentrations in PM10 at the Bou-Ismail measurement station varied from 3.3 µg/m3 (July 2011) to 49.6 µg/m3 (March 2012). The annual mean mass concentrations of ions in the PM10 particulate fraction were Cl- > Na+ > SO42- > Mg2+ > NO3- > Ca2+ > K+ > NH4+ > Oxalate. The change in potassium nss-K + concentrations in PM10 over the course of a year reveals that biomass burning (BB) has an effect on three separate seasons: the beginning of winter (February and March), the end of summer (August), and the autumn (September and October). The origin periods of biomass burning BB identified employing the mapping of hotspots and fires during periods of August and September 2011, 2012, and 2013 underlined the important fires in the surrounding areas of the Mediterranean Sea (Sardinia Islands from Italy, Corsica from France).

BACE1 Inhibitors for Alzheimer's Disease: Current Challenges and Future Perspectives.

Disease-modifying therapies (DMT) for Alzheimer's disease (AD) are highly longed-for. In this quest, anti-amyloid therapies take center stage supported by genetic facts that highlight an imbalance between production and clearance of amyloid-ß peptide (Aß) in AD patients. Indeed, evidence from basic research, human genetic and biomarker studies, suggests the accumulation of Aß as a driver of AD pathogenesis and progression. The aspartic protease ß-site AßPP cleaving enzyme (BACE1) is the initiator for Aß production. Underpinning a critical role for BACE1 in AD pathophysiology are the elevated BACE1 concentration and activity observed in the brain and body fluids of AD patients. Therefore, BACE1 is a prime drug target for reducing Aß levels in early AD. Small-molecule BACE1 inhibitors have been extensively developed for the last 20 years. However, clinical trials with these molecules have been discontinued for futility or safety reasons. Most of the observed adverse side effects were due to other aspartic proteases cross-inhibition, including the homologue BACE2, and to mechanism-based toxicity since BACE1 has substrates with important roles for synaptic plasticity and synaptic homeostasis besides amyloid-ß protein precursor (AßPP). Despite these setbacks, BACE1 persists as a well-validated therapeutic target for which a specific inhibitor with high substrate selectivity may yet to be found. In this review we provide an overview of the evolution in BACE1 inhibitors design pinpointing the molecules that reached advanced phases of clinical trials and the liabilities that precluded adequate trial effects. Finally, we ponder on the challenges that anti-amyloid therapies must overcome to achieve clinical success.

Effect of different levels of whole corn germ on energy values and ileal digestibility in broilers.

This study evaluated the effects of broiler age (A) and levels of replacement (L) of control diet (CD) on the utilization of energy and nutrients of whole corn germ. 720 one-day-old broilers (b) were allocated at completely randomized design to six treatments and six replicates, in three assays: pre-starter (1-8 days, 10 b/cage), starter (15-22 days, 6 b/cage), and grower (28-35 days, 4 b/cage) phases. The treatments were: CD and four test diets (L): 100, 150, 200, 250, or 300 g kg-1 of the CD replaced by WCG levels. The data were adjusted to the response surface model. The stationary points for apparent energy metabolizable (AME) and AME corrected for nitrogen balance (AMEn) were: 4173 and 3591 kcal kg-1, respectively, and coefficients of gross energy (AMCGE), crude protein (AMCCP), dry matter (AMCDM), and ether extract (AMCEE) were: 49.3, 40.4, 72.6, and 61.3%, respectively; and Ileal digestibility coefficient of crude protein (IDCCP), dry matter (IDCDM), digestibility crude protein values (DCP), and digestibility dry matter value (DDM) were: 78.0, 57.96, 8.50, and 56.17%, respectively. The EP for AMEn was at 18 days of age, 28 g kg-1 WCG. There was a correlation between A and L on digestibility and metabolisability of nutrient's WCG.

Quantitative proteomics reveals the dynamic proteome landscape of zebrafish embryos during the maternal-to-zygotic transition.

Maternal-to-zygotic transition (MZT) is central to early embryogenesis. However, its underlying molecular mechanisms are still not well described. Here, we revealed the expression dynamics of 5,000 proteins across four stages of zebrafish embryos during MZT, representing one of the most systematic surveys of proteome landscape of the zebrafish embryos during MZT. Nearly 700 proteins were differentially expressed and were divided into six clusters according to their expression patterns. The proteome expression profiles accurately reflect the main events that happen during the MZT, i.e., zygotic genome activation (ZGA), clearance of maternal mRNAs, and initiation of cellular differentiation and organogenesis. MZT is modulated by many proteins at multiple levels in a collaborative fashion, i.e., transcription factors, histones, histone-modifying enzymes, RNA helicases, and P-body proteins. Significant discrepancies were discovered between zebrafish proteome and transcriptome profiles during the MZT. The proteome dynamics database will be a valuable resource for bettering our understanding of MZT.

Quality assessment of oral antimalarial and antiretroviral medicines used by public health systems in Sahel countries.

Malaria and Human Immunodeficiency Virus infections are among the top 10 causes of death in low income countries. Furthermore, many medicines used in these treatment areas are substandard, which contributes to the high death rate. Using a monitoring system to identify substandard and falsified medicines, the study aims to evaluate the quality of antimalarial and antiretroviral medicines in Sahel countries, assessing site conditions, compliance of medicines with pharmacopoeia tests, formulation equivalence with a reference medicine, and the influence of climate on quality attributes. Ultra Performance Liquid Chromatography methods for eight active pharmaceutical ingredients were validated following the International Conference for Harmonization guideline for its detection and quantification. Quality control consists of visual inspections to detect any misinformation or imperfections and pharmacopeial testing to determine the quality of pharmaceutical products. Medicines which complied with uniformity dosage units and dissolution tests were stored under accelerated conditions for 6 months. Artemether/Lumefantrine and Lopinavir/Ritonavir formulations failed uniformity dosage units and disintegration tests respectively, detecting a total of 28.6% substandard medicines. After 6 months stored under accelerated conditions (40 °C // 75% relative humidity) simulating climatic conditions in Sahel countries, some medicines failed pharmacopeia tests. It demonstrated the influence of these two factors in their quality attributes. This study emphasizes the need of certified quality control laboratories as well as the need for regulatory systems to maintain standards in pharmaceutical manufacturing and distribution in these countries, especially when medicines are transported to rural areas where these climatic conditions are harsher.

Transcriptional profiles associated with coronary artery disease in type 2 diabetes mellitus.

Background: Coronary artery disease (CAD) is a common complication of Type 2 diabetes mellitus (T2DM). Understanding the pathogenesis of this complication is essential in both diagnosis and management. Thus, this study aimed to characterize the presence of CAD in T2DM using molecular markers and pathway analyses. Methods: The study is a sex- and age-frequency matched case-control design comparing 23 unrelated adult Filipinos with T2DM-CAD to 23 controls (DM with CAD). Healthy controls served as a reference. Total RNA from peripheral blood mononuclear cells (PBMCs) underwent whole transcriptomic profiling using the Illumina HumanHT-12 v4.0 expression beadchip. Differential gene expression with gene ontogeny analyses was performed, with supporting correlational analyses using weighted correlation network analysis (WGCNA). Results: The study observed that 458 genes were differentially expressed between T2DM with and without CAD (FDR<0.05). The 5 top genes the transcription factor 3 (TCF3), allograft inflammatory factor 1 (AIF1), nuclear factor, interleukin 3 regulated (NFIL3), paired immunoglobulin-like type 2 receptor alpha (PILRA), and cytoskeleton-associated protein 4 (CKAP4) with AUCs >89%. Pathway analyses show differences in innate immunity activity, which centers on the myelocytic (neutrophilic/monocytic) theme. SNP-module analyses point to a possible causal dysfunction in innate immunity that triggers the CAD injury in T2DM. Conclusion: The study findings indicate the involvement of innate immunity in the development of T2DM-CAD, and potential immunity markers can reflect the occurrence of this injury. Further studies can verify the mechanistic hypothesis and use of the markers.

Differential Gene Expression in Porcine Lung Compartments after Experimental Infection with Mycoplasma hyopneumoniae.

Mycoplasma hyopneumoniae (Mhyo) is the causative agent of porcine enzootic pneumonia (EP), as well as one of the main pathogens involved in the porcine respiratory disease complex. The host-pathogen interaction between Mhyo and infected pigs is complex and not completely understood; however, improving the understanding of these intricacies is essential for the development of effective control strategies of EP. In order to improve our knowledge about this interaction, laser-capture microdissection was used to collect bronchi, bronchi-associated lymphoid tissue, and lung parenchyma from animals infected with different strains of Mhyo, and mRNA expression levels of different molecules involved in Mhyo infection (ICAM1, IL-8, IL-10, IL-23, IFN-α, IFN-γ, TGF-ß, and TNF-α) were analyzed by qPCR. In addition, the quantification of Mhyo load in the different lung compartments and the scoring of macroscopic and microscopic lung lesions were also performed. Strain-associated differences in virulence were observed, as well as the presence of significant differences in expression levels of cytokines among lung compartments. IL-8 and IL-10 presented the highest upregulation, with limited differences between strains and lung compartments. IFN-α was strongly downregulated in BALT, implying a relevant role for this cytokine in the immunomodulation associated with Mhyo infections. IL-23 was also upregulated in all lung compartments, suggesting the potential involvement of a Th17-mediated immune response in Mhyo infections. Our findings highlight the relevance of Th1 and Th2 immune response in cases of EP, shedding light on the gene expression levels of key cytokines in the lung of pigs at a microscopic level.

Microbiological Survey and Evaluation of Antimicrobial Susceptibility Patterns of Microorganisms Obtained from Suspect Cases of Canine Otitis Externa in Gran Canaria, Spain.

A retrospective study of microbiological laboratory results from 2020 to 2022, obtained from a veterinary diagnostic laboratory of the island of Gran Canaria, Spain, focused on canine otitis cases, was performed. The objective of this study was to analyze the pathogen distribution, antimicrobial susceptibility, prevalence of multidrug resistant phenotypes and the role of coinfections in otitis cases in order to provide up-to-date evidence that could support effective control strategies for this prevalent pathology. A total of 604 submissions were processed for the diagnosis of canine external otitis. Of the samples analyzed, 472 were positive for bacterial or fungal growth (78.1%; 95% CI: 74.8-81.4%). A total of 558 microbiological diagnoses were obtained, divided in 421 bacterial (75.4%; 95% CI: 71.8-79.0%) and 137 fungal (24.6%; 95% CI: 20.9-28.1%) identifications. Staphylococcus pseudintermedius, Malassezia pachydermatis and Pseudomonas aeruginosa were the most prevalent microorganisms detected in clinical cases of otitis. High level antimicrobial resistance was found for Pseudomonas aeruginosa (30.7%), Proteus mirabilis (29.4%), Staphylococcus pseudintermedius (25.1%) and Escherichia coli (19%). Multidrug-resistant phenotypes were observed in 47% of the bacteria isolated. In addition, a 26.4% prevalence of methicillin-resistant Staphylococcus pseudintermedius was detected. The high prevalence of antimicrobial resistant phenotypes in these bacteria highlights the current necessity for constant up-to-date prevalence and antimicrobial susceptibility data that can support evidence-based strategies to effectively tackle this animal and public health concern.

Revolutionizing Three-Dimensional Printing: Enhancing Quality Assurance and Point-of-Care Integration through Instrumentation.

Three-dimensional printing in the field of additive manufacturing shows potential for customized medicines and solving gaps in paediatric formulations. Despite successful clinical trials, 3D printing use in pharmaceutical point-of-care is limited by regulatory loopholes and a lack of Pharmacopoeia guidelines to ensure quality. Semi-solid extrusion is a 3D printing technology that stands out for its versatility, but understanding the fluid dynamics of the semi-solid mass is critical. The aim of this research is to look into the advantages of instrumenting a 3D printer with a semi-solid extrusion motor-driven printhead, which is able to record the printing pressure over time, for in situ characterization of the semi-solid mass and quality evaluation of dosage forms. Four formulations using hydrochlorothiazide as the active pharmaceutical ingredient and several excipients were used. Their flow properties were studied at different printing speeds and temperatures using traditional techniques (rheometer and Texture Analyzer) and the proposed semi-solid extrusion motor-driven printhead incorporated into a printing platform. In addition, the influence of printing speed in the printing process was also evaluated by the study of printing pressure and printlet quality. The results demonstrated the similarities between the use of a Texture Analyzer and the semi-solid extrusion motor-driven. However, the latter enables temperature selection and printing speed in accordance with the printing process which are critical printing parameters. In addition, due to the incorporation of a sensor, it was possible to conclude, for the first time, that there is a link between changes in essential printing parameters like printing speed or formulations and variations in printing pressure and printlet quality attributes such as the energy require to obtain a single dosage unit, weight or diameter. This breakthrough holds a lot of potential for assuring the quality of 3D printing dosage forms and paving the way for their future incorporation into point-of-care settings.

Molecular mechanism of dynein-dynactin complex assembly by LIS1.

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