scholarly journals Identification by proximity labeling of novel lipidic and proteinaceous potential partners of the dopamine transporter

2021 ◽  
Author(s):  
Dolores Piniella ◽  
Elena Martínez-Blanco ◽  
David Bartolomé-Martín ◽  
Ana B. Sanz-Martos ◽  
Francisco Zafra
Keyword(s):  
Spatial Proximity ◽  
Dopaminergic Cell ◽  
Experimental Systems ◽  
Cytoplasmic Proteins ◽  
Electrophysiological Recordings ◽  
Pharmacological Targets ◽  
Transient Interactions ◽  
Close Spatial Proximity ◽  
The Brain ◽  
Ubiquitination Machinery

AbstractDopamine (DA) transporters (DATs) are regulated by trafficking and modulatory processes that probably rely on stable and transient interactions with neighboring proteins and lipids. Using proximity-dependent biotin identification (BioID), we found novel potential partners for DAT, including several membrane proteins, such as the transmembrane chaperone 4F2hc, the proteolipid M6a and a potential membrane receptor for progesterone (PGRMC2). We also detected two cytoplasmic proteins: a component of the Cullin1-dependent ubiquitination machinery termed F-box/LRR-repeat protein 2 (FBXL2), and the enzyme inositol 5-phosphatase 2 (SHIP2). Immunoprecipitation (IP) and immunofluorescence studies confirmed either a physical association or a close spatial proximity between these proteins and DAT. M6a, SHIP2 and the Cullin1 system were shown to increase DAT activity in coexpression experiments, suggesting a functional role for their association. Deeper analysis revealed that M6a, which is enriched in neuronal protrusions (filopodia or dendritic spines), colocalized with DAT in these structures. In addition, the product of SHIP2 enzymatic activity (phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2]) was tightly associated with DAT, as shown by co-IP and by colocalization of mCherry-DAT with a specific biosensor for this phospholipid. PI(3,4)P2 strongly stimulated transport activity in electrophysiological recordings, and conversely, inhibition of SHIP2 reduced DA uptake in several experimental systems including striatal synaptosomes and the dopaminergic cell line SH-SY5Y. In summary, here we report several potential new partners for DAT and a novel regulatory lipid, which may represent new pharmacological targets for DAT, a pivotal protein in dopaminergic function of the brain.

scholarly journals A theory for polymicrogyria and brain arteriovenous malformations in HHT

Neurology ◽  
2018 ◽  
Vol 92 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Jesse M. Klostranec ◽  
Long Chen ◽  
Shobhit Mathur ◽  
Jamie McDonald ◽  
Marie E. Faughnan ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Fluid Shear Stress ◽  
Transmembrane Protein ◽  
Dominant Negative ◽  
Spatial Proximity ◽  
Imaging Data ◽  
Fluid Shear ◽  
Brain Avm ◽  
Close Spatial Proximity ◽  
The Brain

Hereditary hemorrhagic telangiectasia (HHT) is generally considered a disorder of endothelial dysfunction, characterized by the development of multiple systemic arteriovenous malformations (AVMs), including within the brain. However, there have recently been a number of reports correlating HHT with malformations of cortical development, of which polymicrogyria is the most common type. Here we present 7 new cases demonstrating polymicrogyria in HHT, 6 of which demonstrate a brain AVM (bAVM) in close spatial proximity, with the aim of providing a common origin for the association. Upon reviewing patient genetics and imaging data and comparing with previously reported findings, we form 2 new conclusions: (1) polymicrogyria in HHT appears exclusively associated with a subset of mutations in the transmembrane protein endoglin that is involved with blood flow–related mechanotransduction signaling during angiogenesis and (2) the polymicrogyria is characteristically unilateral, typically focal, and correlates with vascular regions experiencing low fluid shear stress during corticogenesis in utero. Integrating these with findings in the literature from genetics and molecular biology experiments, we propose a theory suggesting haploinsufficient endoglin mutations, especially those that are dominant-negative, may predispose focal, aberrant hypersprouting angiogenesis during corticogenesis that leads to the production of polymicrogyria. This hypoxic insult may further serve as the revealing trigger for later development of a spatially coincident bAVM. This hypothesis suggests an essential role for endoglin-mediated hemodynamic mechanotransduction in normal corticogenesis.

scholarly journals Distinct Neural Mechanisms Meet Challenges in Dynamic Visual Attention due to Either Load or Object Spacing

2020 ◽  
Vol 32 (1) ◽  
pp. 65-84 ◽  
Author(s):  
Veronica Mäki-Marttunen ◽  
Thomas Hagen ◽  
Bruno Laeng ◽  
Thomas Espeseth
Keyword(s):  
Visual Attention ◽  
Cognitive Processing ◽  
Spatial Proximity ◽  
Physiological Mechanisms ◽  
Close Encounters ◽  
Visuospatial Tasks ◽  
Spatial Interference ◽  
Close Spatial Proximity ◽  
The Brain ◽  
Increasing Load

When engaged in dynamic visuospatial tasks, the brain copes with perceptual and cognitive processing challenges. During multiple-object tracking (MOT), the number of objects to be tracked (i.e., load) imposes attentional demands, but so does spatial interference from irrelevant objects (i.e., close encounters). Presently, it is not clear whether the effect of load on accuracy solely depends on the number of close encounters. If so, the same cognitive and physiological mechanisms deal with increasing load by preparing for and dealing with spatial interference. However, this has never been directly tested. Such knowledge is important to understand the neurophysiology of dynamic visual attention and resolve conflicting views within visual cognition concerning sources of capacity limitations. We varied the processing challenge in MOT task in two ways: the number of targets and the minimum spatial proximity between targets and distractors. In a first experiment, we measured task-induced pupil dilations and saccades during MOT. In a separate cohort, we measured fMRI activity. In both cohorts, increased load and close encounters (i.e., close spatial proximity) led to reduced accuracy in an additive manner. Load was associated with pupil dilations, whereas close encounters were not. Activity in dorsal attentional areas and frequency of saccades were proportionally larger both with higher levels of load and close encounters. Close encounters recruited additionally ventral attentional areas that may reflect orienting mechanisms. The activity in two brainstem nuclei, ventral tegmental area/substantia nigra and locus coeruleus, showed clearly dissociated patterns. Our results constitute convergent evidence indicating that different mechanisms underlie processing challenges due to load and object spacing.

scholarly journals Involvement of loop 5 lysine residues and the N-terminal β-hairpin of the ribotoxin hirsutellin A on its insecticidal activity

2016 ◽  
Vol 397 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Miriam Olombrada ◽  
Lucía García-Ortega ◽  
Javier Lacadena ◽  
Mercedes Oñaderra ◽  
José G. Gavilanes ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
The Other ◽  
Spatial Proximity ◽  
Ribonucleolytic Activity ◽  
The Family ◽  
Lysine Residues ◽  
Hirsutella Thompsonii ◽  
Close Spatial Proximity ◽  
High Degree

Abstract Ribotoxins are cytotoxic members of the family of fungal extracellular ribonucleases best represented by RNase T1. They share a high degree of sequence identity and a common structural fold, including the geometric arrangement of their active sites. However, ribotoxins are larger, with a well-defined N-terminal β-hairpin, and display longer and positively charged unstructured loops. These structural differences account for their cytotoxic properties. Unexpectedly, the discovery of hirsutellin A (HtA), a ribotoxin produced by the invertebrate pathogen Hirsutella thompsonii, showed how it was possible to accommodate these features into a shorter amino acid sequence. Examination of HtA N-terminal β-hairpin reveals differences in terms of length, charge, and spatial distribution. Consequently, four different HtA mutants were prepared and characterized. One of them was the result of deleting this hairpin [Δ(8-15)] while the other three affected single Lys residues in its close spatial proximity (K115E, K118E, and K123E). The results obtained support the general conclusion that HtA active site would show a high degree of plasticity, being able to accommodate electrostatic and structural changes not suitable for the other previously known larger ribotoxins, as the variants described here only presented small differences in terms of ribonucleolytic activity and cytotoxicity against cultured insect cells.

scholarly journals ‘They Eat Potatoes, I Eat Rice’: Symbolic Boundary Making and Space in Neighbour Relations

2011 ◽  
Vol 16 (4) ◽  
pp. 22-33 ◽  
Author(s):  
Gwen Van Eijk
Keyword(s):  
Personal Information ◽  
Spatial Proximity ◽  
Easy Access ◽  
Symbolic Boundaries ◽  
Personal Privacy ◽  
Social Mixing ◽  
Boundary Making ◽  
Close Spatial Proximity ◽  
Depth Interviews ◽  
Symbolic Boundary

This article examines ‘neighbouring’ as the setting in which cross-category relations develop and symbolic boundaries are constructed. The study is based on thirty in-depth interviews with residents living in a multi-ethnic and a mono-ethnic neighbourhood in Rotterdam, the Netherlands. The findings challenge the hoped-for outcomes of social mixing in neighbourhoods, as well as the view that boundary making is something inherent to multi-ethnic neighbourhoods only. Neighbour relations are often setting-specific (relations are interchangeable, scripted and bounded, and passively maintained), which is relevant for understanding the spatiality of neighbouring and the limited exchange of personal information between neighbours. Because neighbouring involves the balancing of personal privacy and close spatial proximity, the exchange of personal information is limited, while spatial proximity ensures easy access to observable (through seeing, hearing and smelling) categorical markers that signify class, ethnicity, lifestyle, etc. In this way, neighbour interaction reconstructs symbolic boundaries rather than breaking them down.

Ontogeny of spatial relationships and social behaviour in juvenile Richardson's ground squirrels

1981 ◽  
Vol 59 (9) ◽  
pp. 1666-1676 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Social Interactions ◽  
Social Behaviour ◽  
Ground Squirrels ◽  
Spatial Proximity ◽  
Family Unit ◽  
Social Patterns ◽  
Rapid Acquisition ◽  
The Family ◽  
Core Areas ◽  
Close Spatial Proximity

The development of spatial and social patterns by juvenile Richardson's ground squirrels, from first emergence from the natal burrow to entry into hibernation, is described. Juveniles enter the aboveground population at [Formula: see text] weeks of age. During the next 4 weeks juveniles remain in close spatial proximity to family members with whom they engage in frequent amicable social interactions. Thereafter, juveniles become increasingly independent from the family unit, establishing their own spatially distinct core areas and exhibiting site-dependent dominance toward nonkin. Typically juveniles remain physically closer to and more amicable with littermates and mother than other conspecifics such that they compose kin clusters, the members of which are agonistic toward members of adjacent kin clusters. Daughters are more likely to continue to reside close to kin as adults than are sons. At 9–10 weeks of age juveniles exhibit the majority of spatial and social patterns characteristic of adults, and at 12 weeks they are behaviourally indistinguishable from adults. Similar rapid acquisition of adult patterns occurs in four other species of ground-dwelling sciurids that are also obligate hibernators and that breed immediately following emergence from their first hibernation.

scholarly journals Active information maintenance in working memory by a sensory cortex

2018 ◽  
Author(s):  
Xiaoxing Zhang ◽  
Wenjun Yan ◽  
Wenliang Wang ◽  
Hongmei Fan ◽  
Ruiqing Hou ◽  
...  
Keyword(s):  
Working Memory ◽  
Piriform Cortex ◽  
Delay Period ◽  
Sensory Cortex ◽  
Critical Function ◽  
Impaired Performance ◽  
Anterior Piriform Cortex ◽  
Electrophysiological Recordings ◽  
Dual Task Paradigm ◽  
The Brain

SummaryWorking memory is a critical function of the brain to maintain and manipulate information over delay periods of seconds. Sensory areas have been implicated in working memory; however, it is debated whether the delay-period activity of sensory regions is actively maintaining information or passively reflecting top-down inputs. We hereby examined the anterior piriform cortex, an olfactory cortex, in head-fixed mice performing a series of olfactory working memory tasks. Information maintenance is necessary in these tasks, especially in a dual-task paradigm in which mice are required to perform another distracting task while actively maintaining information during the delay period. Optogenetic suppression of the piriform cortex activity during the delay period impaired performance in all the tasks.Furthermore, electrophysiological recordings revealed that the delay-period activity of the anterior piriform cortex encoded odor information with or without the distracting task.Thus, this sensory cortex is critical for active information maintenance in working memory.

scholarly journals How multisensory neurons solve causal inference

2021 ◽  
Vol 118 (32) ◽  
pp. e2106235118
Author(s):  
Reuben Rideaux ◽  
Katherine R. Storrs ◽  
Guido Maiello ◽  
Andrew E. Welchman
Keyword(s):  
Motion Estimation ◽  
Causal Inference ◽  
Visual Motion ◽  
Temporal Area ◽  
Medial Superior Temporal ◽  
Electrophysiological Recordings ◽  
Visual Motion Cues ◽  
Integrated Or ◽  
Self Motion ◽  
The Brain

Sitting in a static railway carriage can produce illusory self-motion if the train on an adjoining track moves off. While our visual system registers motion, vestibular signals indicate that we are stationary. The brain is faced with a difficult challenge: is there a single cause of sensations (I am moving) or two causes (I am static, another train is moving)? If a single cause, integrating signals produces a more precise estimate of self-motion, but if not, one cue should be ignored. In many cases, this process of causal inference works without error, but how does the brain achieve it? Electrophysiological recordings show that the macaque medial superior temporal area contains many neurons that encode combinations of vestibular and visual motion cues. Some respond best to vestibular and visual motion in the same direction (“congruent” neurons), while others prefer opposing directions (“opposite” neurons). Congruent neurons could underlie cue integration, but the function of opposite neurons remains a puzzle. Here, we seek to explain this computational arrangement by training a neural network model to solve causal inference for motion estimation. Like biological systems, the model develops congruent and opposite units and recapitulates known behavioral and neurophysiological observations. We show that all units (both congruent and opposite) contribute to motion estimation. Importantly, however, it is the balance between their activity that distinguishes whether visual and vestibular cues should be integrated or separated. This explains the computational purpose of puzzling neural representations and shows how a relatively simple feedforward network can solve causal inference.

Ex Vivo Brain Preparation to Analyze Vocal Pathways of Xenopus Frogs

2021 ◽  
Vol 2021 (9) ◽  
pp. pdb.prot106872
Author(s):  
Ayako Yamaguchi
Keyword(s):  
Neural Activity ◽  
Ex Vivo ◽  
Neural Circuitry ◽  
Neural Basis ◽  
Vocal Production ◽  
Basic Principles ◽  
Electrophysiological Recordings ◽  
The Brain

Understanding the neural basis of behavior is a challenging task for technical reasons. Most methods of recording neural activity require animals to be immobilized, but neural activity associated with most behavior cannot be recorded from an anesthetized, immobilized animal. Using amphibians, however, there has been some success in developing in vitro brain preparations that can be used for electrophysiological and anatomical studies. Here, we describe an ex vivo frog brain preparation from which fictive vocalizations (the neural activity that would have produced vocalizations had the brain been attached to the muscle) can be elicited repeatedly. When serotonin is applied to the isolated brains of male and female African clawed frogs, Xenopus laevis, laryngeal nerve activity that is a facsimile of those that underlie sex-specific vocalizations in vivo can be readily recorded. Recently, this preparation was successfully used in other species within the genus including Xenopus tropicalis and Xenopus victorianus. This preparation allows a variety of techniques to be applied including extracellular and intracellular electrophysiological recordings and calcium imaging during vocal production, surgical and pharmacological manipulation of neurons to evaluate their impact on motor output, and tract tracing of the neural circuitry. Thus, the preparation is a powerful tool with which to understand the basic principles that govern the production of coherent and robust motor programs in vertebrates.

Characterization of Oscillatory Olfactory Interneurones in the Protocerebrum of the Crayfish

1992 ◽  
Vol 167 (1) ◽  
pp. 15-38
Author(s):  
DEFOREST MELLON ◽  
DAVID C. SANDEMAN ◽  
RENATE E. SANDEMAN
Keyword(s):  
Procambarus Clarkii ◽  
Lucifer Yellow ◽  
Freshwater Crayfish ◽  
University Of Virginia ◽  
Olfactory Pathway ◽  
Electrophysiological Recordings ◽  
Burst Period ◽  
Electron Microscopical ◽  
The Brain

1. We obtained intracellular electrophysiological recordings from local interneurones within the hemi-ellipsoid neuropile of the brain in the freshwater crayfish Cherax destructor and Procambarus clarkii. The recordings were made from perfused, isolated head preparations that provided several indications of a healthy physiological condition. 2. The hemi-ellipsoid interneurones are spontaneously active, generating bursts of action potentials at regular intervals. The inter-burst period differs among neurones, varying from about 1.0 s at the shortest periods to around 30 s for the longest periods. 3. Evidence from both electrophysiological recordings and from injection of Lucifer Yellow and Neurobiotin dyes into hemi-ellipsoid interneurones suggests that some of the cells in the populations are electrically coupled to one another. 4. Hemi-ellipsoid interneurones are driven postsynaptically by axons within the lateral protocerebral tract. Experiments with focal electrical stimulation strongly suggest that the pathways responsible include axons of the olfactory-globular tract. These findings support our previous electron microscopical data showing that olfactory-globular tract axons are presynaptic to the hemi-ellipsoid interneurones. 5. These findings support the conclusion that hemi-ellipsoid interneurones are an integral link in the central olfactory pathway of the crayfish. Note: Present address and address for reprint requests: Department of Biology, Gilmer Hall, University of Virginia, Charlottesville, VA 22901, USA.

scholarly journals Adenine DNA methylation, 3D genome organization, and gene expression in the parasiteTrichomonas vaginalis

2020 ◽  
Vol 117 (23) ◽  
pp. 13033-13043
Author(s):  
Ayelen Lizarraga ◽  
Zach Klapholz O’Brown ◽  
Konstantinos Boulias ◽  
Lara Roach ◽  
Eric Lieberman Greer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Trichomonas Vaginalis ◽  
Three Dimensional ◽  
Wide Distribution ◽  
Spatial Proximity ◽  
Regulation Of Transcription ◽  
3D Genome ◽  
Intergenic Regions ◽  
Close Spatial Proximity

Trichomonas vaginalisis a common sexually transmitted parasite that colonizes the human urogenital tract causing infections that range from asymptomatic to highly inflammatory. Recent works have highlighted the importance of histone modifications in the regulation of transcription and parasite pathogenesis. However, the nature of DNA methylation in the parasite remains unexplored. Using a combination of immunological techniques and ultrahigh-performance liquid chromatography (UHPLC), we analyzed the abundance of DNA methylation in strains with differential pathogenicity demonstrating that N6-methyladenine (6mA), and not 5‐methylcytosine (5mC), is the main DNA methylation mark inT. vaginalis. Genome-wide distribution of 6mA reveals that this mark is enriched at intergenic regions, with a preference for certain superfamilies of DNA transposable elements. We show that 6mA inT. vaginalisis associated with silencing when present on genes. Interestingly, bioinformatics analysis revealed the presence of transcriptionally active or repressive intervals flanked by 6mA-enriched regions, and results from chromatin conformation capture (3C) experiments suggest these 6mA flanked regions are in close spatial proximity. These associations were disrupted when parasites were treated with the demethylation activator ascorbic acid. This finding revealed a role for 6mA in modulating three-dimensional (3D) chromatin structure and gene expression in this divergent member of the Excavata.

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