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1.
bioRxiv ; 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37577547

RESUMEN

Elevated plasma branched-chain amino acids (BCAAs) are strongly associated with obesity, insulin resistance (IR), and diabetes in humans and rodent models. However, the mechanisms of BCAA dysregulation and its systemic, organ, and cell-specific implications in the development of obesity and IR are not well understood. To gain mechanistic insight into the causes and effects of plasma BCAA elevations, we leveraged mouse models with high circulating BCAA levels prior to the onset of obesity and IR. Young mice lacking ankyrin-B in white adipose tissue (WAT) or bearing an ankyrin-B variant that causes age-driven metabolic syndrome exhibit downregulation of BCAA catabolism selectively in WAT and excess plasma BCAAs. Using cellular assays, we demonstrated that ankyrin-B promotes the surface localization of the amino acid transporter Asct2 in white adipocytes, and its deficit impairs BCAA uptake. Excess BCAA supplementation worsened glucose tolerance and insulin sensitivity across genotypes. In contrast, BCAA overconsumption only increased adiposity in control mice, implicating WAT utilization of BCAAs in their obesogenic effects. These results shed light into the mechanistic underpinnings of metabolic syndrome caused by ankyrin-B deficits and provide new evidence of the relevance of WAT in the regulation of systemic BCAA levels, adiposity, and glucose homeostasis.

2.
Nat Rev Neurosci ; 24(4): 195-212, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36697767

RESUMEN

Spectrins are cytoskeletal proteins that are expressed ubiquitously in the mammalian nervous system. Pathogenic variants in SPTAN1, SPTBN1, SPTBN2 and SPTBN4, four of the six genes encoding neuronal spectrins, cause neurological disorders. Despite their structural similarity and shared role as molecular organizers at the cell membrane, spectrins vary in expression, subcellular localization and specialization in neurons, and this variation partly underlies non-overlapping disease presentations across spectrinopathies. Here, we summarize recent progress in discerning the local and long-range organization and diverse functions of neuronal spectrins. We provide an overview of functional studies using mouse models, which, together with growing human genetic and clinical data, are helping to illuminate the aetiology of neurological spectrinopathies. These approaches are all critical on the path to plausible therapeutic solutions.


Asunto(s)
Enfermedades del Sistema Nervioso , Espectrina , Animales , Ratones , Humanos , Espectrina/genética , Espectrina/metabolismo , Enfermedades del Sistema Nervioso/genética , Neuronas/metabolismo , Membrana Celular/metabolismo , Mamíferos/metabolismo
3.
Front Cell Infect Microbiol ; 12: 906563, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35651755

RESUMEN

Background: Ibrexafungerp (SCY-078) is the newest oral and intravenous antifungal drug with broad activity, currently undergoing clinical trials for invasive candidiasis. Objective: The aim of this study was to assess the in vitro activity of ibrexafungerp and comparators against a collection of 434 European blood isolates of Candida. Methods: Ibrexafungerp, caspofungin, fluconazole, and micafungin minimum inhibitory concentrations (MICs) were collected from 12 European laboratories for 434 blood isolates, including 163 Candida albicans, 108 Candida parapsilosis, 60 Candida glabrata, 40 Candida tropicalis, 29 Candida krusei, 20 Candida orthopsilosis, 6 Candida guilliermondii, 2 Candida famata, 2 Candida lusitaniae, and 1 isolate each of Candida bracarensis, Candida catenulata, Candida dubliniensis, and Candida kefyr. MICs were determined by the EUCAST broth microdilution method, and isolates were classified according to recommended clinical breakpoints and epidemiological cutoffs. Additionally, 22 Candida auris from different clinical specimens were evaluated. Results: Ibrexafungerp MICs ranged from 0.016 to ≥8 mg/L. The lowest ibrexafungerp MICs were observed for C. albicans (geometric MIC 0.062 mg/L, MIC range 0.016-0.5 mg/L) and the highest ibrexafungerp MICs were observed for C. tropicalis (geometric MIC 0.517 mg/L, MIC range 0.06-≥8 mg/L). Modal MICs/MIC50s (mg/L) against Candida spp. were 0.125/0.06 for C. albicans, 0.5/0.5 for C. parapsilosis, 0.25/0.25 for C. glabrata, 0.5/0.5 for C. tropicalis, 1/1 for C. krusei, 4/2 for C. orthopsilosis, and 0.5/0.5 for C. auris. Ibrexafungerp showed activity against fluconazole- and echinocandin-resistant isolates. If adopting wild-type upper limits, a non-wild-type phenotype for ibrexafungerp was only observed for 16/434 (3.7%) isolates: 11 (4.6%) C. parapsilosis, 4 (5%) C. glabrata, and 1 (2.5%) C. tropicalis. Conclusion: Ibrexafungerp showed a potent in vitro activity against Candida.


Asunto(s)
Antifúngicos , Candidiasis Invasiva , Antifúngicos/farmacología , Candida , Candida albicans , Candida glabrata , Candida parapsilosis , Candida tropicalis , Candidiasis Invasiva/microbiología , Fluconazol/farmacología , Glicósidos , Micafungina , Triterpenos
4.
Elife ; 102021 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-34812142

RESUMEN

Variants in the high confident autism spectrum disorder (ASD) gene ANK2 target both ubiquitously expressed 220 kDa ankyrin-B and neurospecific 440 kDa ankyrin-B (AnkB440) isoforms. Previous work showed that knock-in mice expressing an ASD-linked Ank2 variant yielding a truncated AnkB440 product exhibit ectopic brain connectivity and behavioral abnormalities. Expression of this variant or loss of AnkB440 caused axonal hyperbranching in vitro, which implicated AnkB440 microtubule bundling activity in suppressing collateral branch formation. Leveraging multiple mouse models, cellular assays, and live microscopy, we show that AnkB440 also modulates axon collateral branching stochastically by reducing the number of F-actin-rich branch initiation points. Additionally, we show that AnkB440 enables growth cone (GC) collapse in response to chemorepellent factor semaphorin 3 A (Sema 3 A) by stabilizing its receptor complex L1 cell adhesion molecule/neuropilin-1. ASD-linked ANK2 variants failed to rescue Sema 3A-induced GC collapse. We propose that impaired response to repellent cues due to AnkB440 deficits leads to axonal targeting and branch pruning defects and may contribute to the pathogenicity of ANK2 variants.


Asunto(s)
Ancirinas/genética , Orientación del Axón/genética , Axones/fisiología , Semaforina-3A/genética , Transducción de Señal/genética , Animales , Ancirinas/metabolismo , Ratones , Semaforina-3A/metabolismo
5.
Sensors (Basel) ; 20(15)2020 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-32751248

RESUMEN

Sensor networks in real-world environments, such as smart cities or ambient intelligent platforms, provide applications with large and heterogeneous sets of data streams. Outliers-observations that do not conform to an expected behavior-has then turned into a crucial task to establish and maintain secure and reliable databases in this kind of platforms. However, the procedures to obtain accurate models for erratic observations have to operate with low complexity in terms of storage and computational time, in order to attend the limited processing and storage capabilities of the sensor nodes in these environments. In this work, we analyze three binary classifiers based on three statistical prediction models-ARIMA (Auto-Regressive Integrated Moving Average), GAM (Generalized Additive Model), and LOESS (LOcal RegrESSion)-for outlier detection with low memory consumption and computational time rates. As a result, we provide (1) the best classifier and settings to detect outliers, based on the ARIMA model, and (2) two real-world classified datasets as ground truths for future research.

6.
Cytoskeleton (Hoboken) ; 77(3-4): 129-148, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32034889

RESUMEN

The highly polarized, typically very long, and nonmitotic nature of neurons present them with unique challenges in the maintenance of their homeostasis. This architectural complexity serves a rich and tightly controlled set of functions that enables their fast communication with neighboring cells and endows them with exquisite plasticity. The submembrane neuronal cytoskeleton occupies a pivotal position in orchestrating the structural patterning that determines local and long-range subcellular specialization, membrane dynamics, and a wide range of signaling events. At its center is the partnership between ankyrins and spectrins, which self-assemble with both remarkable long-range regularity and micro- and nanoscale specificity to precisely position and stabilize cell adhesion molecules, membrane transporters, ion channels, and other cytoskeletal proteins. To accomplish these generally conserved, but often functionally divergent and spatially diverse, roles these partners use a combinatorial program of a couple of dozens interacting family members, whose code is not fully unraveled. In a departure from their scaffolding roles, ankyrins and spectrins also enable the delivery of material to the plasma membrane by facilitating intracellular transport. Thus, it is unsurprising that deficits in ankyrins and spectrins underlie several neurodevelopmental, neurodegenerative, and psychiatric disorders. Here, I summarize key aspects of the biology of spectrins and ankyrins in the mammalian neuron and provide a snapshot of the latest advances in decoding their roles in the nervous system.


Asunto(s)
Ancirinas/metabolismo , Transporte Biológico/fisiología , Neuronas/metabolismo , Espectrina/metabolismo
7.
J Vis Exp ; (150)2019 08 28.
Artículo en Inglés | MEDLINE | ID: mdl-31524875

RESUMEN

Astrocytes are among the most abundant cell types in the adult brain, where they play key roles in a multiplicity of functions. As a central player in brain homeostasis, astrocytes supply neurons with vital metabolites and buffer extracellular water, ions, and glutamate. An integral component of the "tri-partite" synapse, astrocytes are also critical in the formation, pruning, maintenance, and modulation of synapses. To enable these highly interactive functions, astrocytes communicate among themselves and with other glial cells, neurons, the brain vasculature, and the extracellular environment through a multitude of specialized membrane proteins that include cell adhesion molecules, aquaporins, ion channels, neurotransmitter transporters, and gap junction molecules. To support this dynamic flux, astrocytes, like neurons, rely on tightly coordinated and efficient intracellular transport. Unlike neurons, where intracellular trafficking has been extensively delineated, microtubule-based transport in astrocytes has been less studied. Nonetheless, exo- and endocytic trafficking of cell membrane proteins and intracellular organelle transport orchestrates astrocytes' normal biology, and these processes are often affected in disease or in response to injury. Here we present a straightforward protocol to culture high quality murine astrocytes, to fluorescently label astrocytic proteins and organelles of interest, and to record their intracellular transport dynamics using time-lapse confocal microscopy. We also demonstrate how to extract and quantify relevant transport parameters from the acquired movies using available image analysis software (i.e., ImageJ/FIJI) plugins.


Asunto(s)
Astrocitos/metabolismo , Espacio Intracelular/metabolismo , Orgánulos/metabolismo , Animales , Astrocitos/citología , Transporte Biológico , Encéfalo/metabolismo , Células Cultivadas , Proteínas Fluorescentes Verdes/metabolismo , Ratones
8.
Proc Natl Acad Sci U S A ; 116(30): 15262-15271, 2019 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-31285321

RESUMEN

Giant ankyrin-B (ankB) is a neurospecific alternatively spliced variant of ANK2, a high-confidence autism spectrum disorder (ASD) gene. We report that a mouse model for human ASD mutation of giant ankB exhibits increased axonal branching in cultured neurons with ectopic CNS axon connectivity, as well as with a transient increase in excitatory synapses during postnatal development. We elucidate a mechanism normally limiting axon branching, whereby giant ankB localizes to periodic axonal plasma membrane domains through L1 cell-adhesion molecule protein, where it couples microtubules to the plasma membrane and prevents microtubule entry into nascent axon branches. Giant ankB mutation or deficiency results in a dominantly inherited impairment in selected communicative and social behaviors combined with superior executive function. Thus, gain of axon branching due to giant ankB-deficiency/mutation is a candidate cellular mechanism to explain aberrant structural connectivity and penetrant behavioral consequences in mice as well as humans bearing ASD-related ANK2 mutations.


Asunto(s)
Ancirinas/genética , Trastorno del Espectro Autista/genética , Molécula L1 de Adhesión de Célula Nerviosa/genética , Proyección Neuronal , Neuronas/metabolismo , Sinapsis/metabolismo , Empalme Alternativo , Animales , Ancirinas/metabolismo , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/fisiopatología , Conducta Animal , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Conectoma , Modelos Animales de Enfermedad , Función Ejecutiva/fisiología , Expresión Génica , Técnicas de Sustitución del Gen , Humanos , Masculino , Ratones , Ratones Transgénicos , Microtúbulos/metabolismo , Microtúbulos/ultraestructura , Mutación , Molécula L1 de Adhesión de Célula Nerviosa/metabolismo , Neuronas/patología , Cultivo Primario de Células , Conducta Social , Sinapsis/patología
9.
Proc Natl Acad Sci U S A ; 116(31): 15686-15695, 2019 07 30.
Artículo en Inglés | MEDLINE | ID: mdl-31209033

RESUMEN

ßII-spectrin is the generally expressed member of the ß-spectrin family of elongated polypeptides that form micrometer-scale networks associated with plasma membranes. We addressed in vivo functions of ßII-spectrin in neurons by knockout of ßII-spectrin in mouse neural progenitors. ßII-spectrin deficiency caused severe defects in long-range axonal connectivity and axonal degeneration. ßII-spectrin-null neurons exhibited reduced axon growth, loss of actin-spectrin-based periodic membrane skeleton, and impaired bidirectional axonal transport of synaptic cargo. We found that ßII-spectrin associates with KIF3A, KIF5B, KIF1A, and dynactin, implicating spectrin in the coupling of motors and synaptic cargo. ßII-spectrin required phosphoinositide lipid binding to promote axonal transport and restore axon growth. Knockout of ankyrin-B (AnkB), a ßII-spectrin partner, primarily impaired retrograde organelle transport, while double knockout of ßII-spectrin and AnkB nearly eliminated transport. Thus, ßII-spectrin promotes both axon growth and axon stability through establishing the actin-spectrin-based membrane-associated periodic skeleton as well as enabling axonal transport of synaptic cargo.


Asunto(s)
Axones/metabolismo , Encéfalo/metabolismo , Membrana Celular/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Espectrina/metabolismo , Animales , Encéfalo/citología , Membrana Celular/genética , Conectoma , Ratones , Ratones Noqueados , Proteínas del Tejido Nervioso/genética , Espectrina/genética
10.
Cell Rep ; 24(5): 1254-1265, 2018 07 31.
Artículo en Inglés | MEDLINE | ID: mdl-30067980

RESUMEN

Lysosomes play a critical role in maintenance of the integrity of neuronal function, and mutations in genes that contribute to lysosome formation, transport, and activity are associated with neurodegenerative disorders. Recently, the multisubunit complex, BLOC-one-related complex (BORC), has been shown to be involved in positioning lysosomes within the cytoplasm, although the consequences of altered BORC function in adult animals have not been established. We show that a spontaneous truncation mutation in the mouse Borcs7 gene, identified through whole-genome sequencing followed by genetic complementation, results in progressive axonal dystrophy with dramatic impairment of motor function. Furthermore, mice homozygous for deletion of the entire Borcs7 coding sequence die shortly after birth, and neurons cultured from these animals show impaired centrifugal transport of lysosomes. This identifies BORCS7 as a central factor in axonal transport of lysosomes and a possible target for improving disease-related disturbances in this important function.


Asunto(s)
Transporte Axonal , Proteínas de Membrana de los Lisosomas/genética , Distrofias Neuroaxonales/genética , Animales , Femenino , Locomoción , Mutación con Pérdida de Función , Lisosomas/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neuronas/metabolismo
11.
Proc Natl Acad Sci U S A ; 114(48): 12743-12748, 2017 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-29133412

RESUMEN

Obesity typically is linked to caloric imbalance as a result of overnutrition. Here we propose a cell-autonomous mechanism for adiposity as a result of persistent cell surface glucose transporter type 4 (GLUT4) in adipocytes resulting from impaired function of ankyrin-B (AnkB) in coupling GLUT4 to clathrin-mediated endocytosis. Adipose tissue-specific AnkB-KO mice develop obesity and progressive pancreatic islet dysfunction with age or high-fat diet (HFD). AnkB-deficient adipocytes exhibit increased lipid accumulation associated with increased glucose uptake and impaired endocytosis of GLUT4. AnkB binds directly to GLUT4 and clathrin and promotes their association in adipocytes. AnkB variants that fail to restore normal lipid accumulation and GLUT4 localization in adipocytes are present in 1.3% of European Americans and 8.4% of African Americans, and are candidates to contribute to obesity susceptibility in humans.


Asunto(s)
Adipocitos/metabolismo , Adiposidad/genética , Ancirinas/genética , Transportador de Glucosa de Tipo 4/genética , Glucosa/metabolismo , Obesidad/genética , Adipocitos/patología , Animales , Ancirinas/química , Ancirinas/metabolismo , Transporte Biológico , Población Negra , Clatrina/genética , Clatrina/metabolismo , Dieta Alta en Grasa/efectos adversos , Endocitosis , Regulación de la Expresión Génica , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/patología , Masculino , Ratones , Ratones Noqueados , Modelos Moleculares , Mutación , Obesidad/etiología , Obesidad/metabolismo , Obesidad/patología , Unión Proteica , Estructura Secundaria de Proteína , Transducción de Señal , Población Blanca
12.
Elife ; 52016 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-27718357

RESUMEN

Endosomal membrane trafficking requires coordination between phosphoinositide lipids, Rab GTPases, and microtubule-based motors to dynamically determine endosome identity and promote long-range organelle transport. Here we report that ankyrin-B (AnkB), through integrating all three systems, functions as a critical node in the protein circuitry underlying polarized recycling of α5ß1-integrin in mouse embryonic fibroblasts, which enables persistent fibroblast migration along fibronectin gradients. AnkB associates with phosphatidylinositol 3-phosphate (PI3P)-positive organelles in fibroblasts and binds dynactin to promote their long-range motility. We demonstrate that AnkB binds to Rab GTPase Activating Protein 1-Like (RabGAP1L) and recruits it to PI3P-positive organelles, where RabGAP1L inactivates Rab22A, and promotes polarized trafficking to the leading edge of migrating fibroblasts. We further determine that α5ß1-integrin depends on an AnkB/RabGAP1L complex for polarized recycling. Our results reveal AnkB as an unexpected key element in coordinating polarized transport of α5ß1-integrin and likely of other specialized endocytic cargos.


Asunto(s)
Ancirinas/metabolismo , Complejo Dinactina/metabolismo , Proteínas Activadoras de GTPasa/metabolismo , Integrina alfa5beta1/metabolismo , Animales , Ancirinas/genética , Complejo Dinactina/genética , Endosomas/genética , Endosomas/metabolismo , Fibroblastos/metabolismo , Proteínas Activadoras de GTPasa/genética , Antígenos de Histocompatibilidad , Humanos , Integrina alfa5beta1/genética , Lípidos/genética , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Ratones , Fosfatos de Fosfatidilinositol/metabolismo , Unión Proteica
13.
Curr Top Membr ; 77: 143-84, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26781832

RESUMEN

Ankyrins are membrane-associated proteins that together with their spectrin partners are responsible for micron-scale organization of vertebrate plasma membranes, including those of erythrocytes, excitable membranes of neurons and heart, lateral membrane domains of columnar epithelial cells, and striated muscle. Ankyrins coordinate functionally related membrane transporters and cell adhesion proteins (15 protein families identified so far) within plasma membrane compartments through independently evolved interactions of intrinsically disordered sequences with a highly conserved peptide-binding groove formed by the ANK repeat solenoid. Ankyrins are coupled to spectrins, which are elongated organelle-sized proteins that form mechanically resilient arrays through cross-linking by specialized actin filaments. In addition to protein interactions, cellular targeting and assembly of spectrin/ankyrin domains also critically depend on palmitoylation of ankyrin-G by aspartate-histidine-histidine-cysteine 5/8 palmitoyltransferases, as well as interaction of beta-2 spectrin with phosphoinositide lipids. These lipid-dependent spectrin/ankyrin domains are not static but are locally dynamic and determine membrane identity through opposing endocytosis of bulk lipids as well as specific proteins. A partnership between spectrin, ankyrin, and cell adhesion molecules first emerged in bilaterians over 500 million years ago. Ankyrin and spectrin may have been recruited to plasma membranes from more ancient roles in organelle transport. The basic bilaterian spectrin-ankyrin toolkit markedly expanded in vertebrates through gene duplications combined with variation in unstructured intramolecular regulatory sequences as well as independent evolution of ankyrin-binding activity by ion transporters involved in action potentials and calcium homeostasis. In addition, giant vertebrate ankyrins with specialized roles in axons acquired new coding sequences by exon shuffling. We speculate that early axon initial segments and epithelial lateral membranes initially were based on spectrin-ankyrin-cell adhesion molecule assemblies and subsequently served as "incubators," where ion transporters independently acquired ankyrin-binding activity through positive selection.


Asunto(s)
Adaptación Fisiológica , Ancirinas/metabolismo , Membrana Celular/metabolismo , Espectrina/metabolismo , Vertebrados , Animales , Humanos
14.
J Clin Invest ; 125(8): 3087-102, 2015 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-26168218

RESUMEN

Rare functional variants of ankyrin-B have been implicated in human disease, including hereditary cardiac arrhythmia and type 2 diabetes (T2D). Here, we developed murine models to evaluate the metabolic consequences of these alterations in vivo. Specifically, we generated knockin mice that express either the human ankyrin-B variant R1788W, which is present in 0.3% of North Americans of mixed European descent and is associated with T2D, or L1622I, which is present in 7.5% of African Americans. Young AnkbR1788W/R1788W mice displayed primary pancreatic ß cell insufficiency that was characterized by reduced insulin secretion in response to muscarinic agonists, combined with increased peripheral glucose uptake and concomitantly increased plasma membrane localization of glucose transporter 4 (GLUT4) in skeletal muscle and adipocytes. In contrast, older AnkbR1788W/R1788W and AnkbL1622I/L1622I mice developed increased adiposity, a phenotype that was reproduced in cultured adipocytes, and insulin resistance. GLUT4 trafficking was altered in animals expressing mutant forms of ankyrin-B, and we propose that increased cell surface expression of GLUT4 in skeletal muscle and fatty tissue of AnkbR1788W/R1788W mice leads to the observed age-dependent adiposity. Together, our data suggest that ankyrin-B deficiency results in a metabolic syndrome that combines primary pancreatic ß cell insufficiency with peripheral insulin resistance and is directly relevant to the nearly one million North Americans bearing the R1788W ankyrin-B variant.


Asunto(s)
Adiposidad/genética , Envejecimiento , Ancirinas , Células Secretoras de Insulina , Síndrome Metabólico , Mutación Missense , Envejecimiento/genética , Envejecimiento/metabolismo , Envejecimiento/patología , Sustitución de Aminoácidos , Animales , Ancirinas/genética , Ancirinas/metabolismo , Transportador de Glucosa de Tipo 4/genética , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Insulina/genética , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología , Masculino , Síndrome Metabólico/genética , Síndrome Metabólico/metabolismo , Síndrome Metabólico/patología , Ratones , Ratones Mutantes , Músculo Esquelético/metabolismo , Músculo Esquelético/patología
15.
J Cell Biol ; 207(6): 735-52, 2014 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-25533844

RESUMEN

Axon growth requires long-range transport of organelles, but how these cargoes recruit their motors and how their traffic is regulated are not fully resolved. In this paper, we identify a new pathway based on the class III PI3-kinase (PIK3C3), ankyrin-B (AnkB), and dynactin, which promotes fast axonal transport of synaptic vesicles, mitochondria, endosomes, and lysosomes. We show that dynactin associates with cargo through AnkB interactions with both the dynactin subunit p62 and phosphatidylinositol 3-phosphate (PtdIns(3)P) lipids generated by PIK3C3. AnkB knockout resulted in shortened axon tracts and marked reduction in membrane association of dynactin and dynein, whereas it did not affect the organization of spectrin-actin axonal rings imaged by 3D-STORM. Loss of AnkB or of its linkages to either p62 or PtdIns(3)P or loss of PIK3C3 all impaired organelle transport and particularly retrograde transport in hippocampal neurons. Our results establish new functional relationships between PIK3C3, dynactin, and AnkB that together promote axonal transport of organelles and are required for normal axon length.


Asunto(s)
Ancirinas/metabolismo , Transporte Axonal , Axones/fisiología , Fosfatidilinositol 3-Quinasas Clase III/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Animales , Aumento de la Célula , Células Cultivadas , Complejo Dinactina , Femenino , Hipocampo/citología , Masculino , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Transgénicos , Microtúbulos/metabolismo , Orgánulos/metabolismo
16.
Elife ; 32014 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-25535840

RESUMEN

Actin, spectrin, and associated molecules form a periodic sub-membrane lattice structure in axons. How this membrane skeleton is developed and why it preferentially forms in axons are unknown. Here, we studied the developmental mechanism of this lattice structure. We found that this structure emerged early during axon development and propagated from proximal regions to distal ends of axons. Components of the axon initial segment were recruited to the lattice late during development. Formation of the lattice was regulated by the local concentration of ßII spectrin, which is higher in axons than in dendrites. Increasing the dendritic concentration of ßII spectrin by overexpression or by knocking out ankyrin B induced the formation of the periodic structure in dendrites, demonstrating that the spectrin concentration is a key determinant in the preferential development of this structure in axons and that ankyrin B is critical for the polarized distribution of ßII spectrin in neurites.


Asunto(s)
Actinas/metabolismo , Axones/metabolismo , Membrana Celular/metabolismo , Espectrina/metabolismo , Actinas/química , Ancirinas/metabolismo , Espectrina/química
17.
Curr Top Membr ; 72: 1-37, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24210426

RESUMEN

Spectrin and ankyrin are membrane skeletal proteins that contribute to mechanical support of plasma membranes and micron-scale organization of diverse membrane-spanning proteins. This chapter provides a plausible scenario for the evolution of ankyrin- and spectrin-based membrane domains with a focus on vertebrates. The analysis integrates recent phylogenetic information with functional analyses of spectrin and ankyrin in erythrocytes, axon initial segments and nodes of Ranvier in neurons, T-tubules and intercalated disks of cardiomyocytes, lateral membrane domains of epithelial cells, and costameres of striated muscle. A core spectrin-ankyrin mechanism for coordinating membrane-spanning proteins and mechanically stabilizing membrane bilayers was expanded in vertebrates by gene duplication events, insertion of giant alternately spliced exons of axonal ankyrins, and a versatile peptide-binding fold of ANK repeats that facilitated acquisition of new protein partners. Cell adhesion molecules (CAM), including dystroglycan, L1 CAM family members, and cadherins, are the earliest examples of membrane-spanning proteins with ankyrin-binding motifs and were all present in urochordates. In contrast, ion channels have continued to evolve ankyrin-binding sites in vertebrates. These considerations suggest a model where proto-domains formed through interaction of ankyrin and spectrin with CAMs. These proto-domains then became populated with ion channels that developed ankyrin-binding activity with selective pressure provided by optimization of physiological function. The best example is the axon initial segment where ankyrin-binding activity evolved sequentially and independently first in L1 CAMs, then in voltage-gated sodium channels, and finally in KCNQ2/3 channels, with the selective advantage of fast and precisely regulated signaling.


Asunto(s)
Ancirinas/metabolismo , Evolución Biológica , Membrana Celular/metabolismo , Espectrina/metabolismo , Animales , Ancirinas/química , Axones/metabolismo , Membrana Celular/química , Células Epiteliales/citología , Células Epiteliales/metabolismo , Eritrocitos/citología , Eritrocitos/metabolismo , Humanos , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Espectrina/química
18.
J Cell Biol ; 189(1): 143-58, 2010 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-20368622

RESUMEN

Spinocerebellar ataxia type 5 (SCA5) is an autosomal dominant neurodegenerative disorder caused by mutations in the SPBTN2 gene encoding beta-III-spectrin. To investigate the molecular basis of SCA5, we established a series of transgenic Drosophila models that express human beta-III-spectrin or fly beta-spectrin proteins containing SCA5 mutations. Expression of the SCA5 mutant spectrin in the eye causes a progressive neurodegenerative phenotype, and expression in larval neurons results in posterior paralysis, reduced synaptic terminal growth, and axonal transport deficits. These phenotypes are genetically enhanced by both dynein and dynactin loss-of-function mutations. In summary, we demonstrate that SCA5 mutant spectrin causes adult-onset neurodegeneration in the fly eye and disrupts fundamental intracellular transport processes that are likely to contribute to this progressive neurodegenerative disease.


Asunto(s)
Transporte Axonal/genética , Drosophila/genética , Mutación , Degeneración Nerviosa/genética , Espectrina/genética , Ataxias Espinocerebelosas/genética , Animales , Animales Modificados Genéticamente , Drosophila/metabolismo , Femenino , Humanos , Masculino , Degeneración Nerviosa/metabolismo , Espectrina/metabolismo , Ataxias Espinocerebelosas/metabolismo
19.
Rev. medica electron ; 28(6)nov.-dic. 2006. ilus, tab
Artículo en Español | CUMED | ID: cum-30387

RESUMEN

Se realizó una intervención educativa con padres e hijos con el fin de sensibilizarlos al abandono de prácticas inadecuadas que les producen deformaciones dentofaciales a través de la Consejería de Prevención de Ortodoncia, creada en el curso 2001-2002 y que continúa funcionando en la actualidad en la clínica “13 de Marzo”, Área de Salud ”Héroes del Moncada”, municipio Cárdenas, con padres y niños de preescolar y 1er. grado que presentaron diferentes hábitos bucales deformantes, siendo atendidos por una Estomatóloga y una Técnica de Atención Estomatológica con experiencias en la actividad de Promoción y Prevención de la Salud. Se incluye la familia, pues ella constituye el centro de las relaciones de la vida en común, siendo necesario que conocieran los problemas presentados por sus hijos y el apoyo a brindarles desde el punto de vista psicológico y espiritual. El efecto se multiplica, porque el trabajo en equipo facilita la solución de los problemas en la consulta, además de enriquecer los conocimientos del profesional y de los padres. Se realizaron un total de 527 sesiones de consultas con 143 hábitos erradicados. Este método, además de ser sencillo y práctico, evita la utilización de recursos materiales costosos y deficitarios en la actualidad...(AU)


Asunto(s)
Humanos , Niño , Ortodoncia Preventiva/educación , Ortodoncia Preventiva/métodos , Atención Odontológica/métodos , Educación en Salud Dental/métodos , Relaciones Dentista-Paciente , Familia/psicología
20.
Rev. medica electron ; 28(6)nov.-dic. 2006. ilus, tab
Artículo en Español | CUMED | ID: cum-30386

RESUMEN

Se realizó una investigación aplicada con carácter retrospectivo experimental en el Área de Salud “Héroes del Moncada”, del municipio de Cárdenas, en la clínica estomatológica “13 de Marzo”, del trabajo realizado durante 13 años con el fin de disminuir los hábitos bucales deformantes. Se muestran los resultados obtenidos en preescolar y primer grado de escuelas primarias de los controles de hábitos bucales deformantes y la aplicación de formas alternativas de trabajos presentados con resultados positivos en diferentes Jornadas Científicas y Fórum de Ciencia y Técnica desde el año 1992 hasta la fecha. Todo esto lo aplicamos a través de la Consejería de Salud bucal con actividades relacionadas con la Prevención de maloclusiones dentarias, creada en el curso 2001-2002 y que continúa funcionando en la actualidad, siendo atendida por un Estomatólogo y una Técnica en Atención Estomatológica con experiencia en la actividad de promoción y prevención de salud. Se incluyó, además, a la familia, ya que ésta constituye el centro de las relaciones de la vida en común, siendo necesario que conocieran los problemas presentados por sus hijos y el apoyo que debían brindarles desde el punto de vista psicológico y espiritual. El efecto se multiplicó, porque el trabajo en equipo facilitó la solución de los problemas en la consulta, también enriqueció los conocimientos de profesionales, técnicos y padres de familia...(AU)


Asunto(s)
Humanos , Niño , Maloclusión/etiología , Maloclusión/prevención & control , Familia/psicología , Educación del Paciente como Asunto/métodos , Odontología Preventiva/educación , Odontología Preventiva/métodos , Ortodoncia Preventiva/educación , Ortodoncia Preventiva/métodos
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