Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 99
Filtrar
2.
J Pediatr Genet ; 13(2): 139-143, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38721582

RESUMO

Townes-Brocks syndrome (TBS) is a rare syndrome characterized by triad of anal, ear, and thumb anomalies. Further malformations/anomalies include congenital heart diseases, foot malformations, sensorineural and/or conductive hearing impairment, genitourinary malformations, and anomalies of eye and nervous system. Definitive diagnosis for TBS is confirmed by molecular analysis for mutations in the SALL1 gene. Only one known case of TBS with absent pulmonary valve syndrome (APVS) has been previously described to our knowledge. Here, we report a newborn diagnosed with TBS with APVS and tetralogy of Fallot (TOF) who was found to carry the most common pathogenic SALL1 gene mutation c.826C > T (p.R276X), with its surgical repair and postoperative follow-up. To our knowledge, this is the first genotyped case of TBS from Turkey to date. TBS should be suspected in the presence of ear, anal, and thumb malformations in a neonate. If a patient with TBS and TOF-APVS needs preoperative ventilation within the first months of life, this implies prolonged postoperative intubation and increased risk of mortality.

3.
Geroscience ; 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38683289

RESUMO

Industrialized environments, despite benefits such as higher levels of formal education and lower rates of infections, can also have pernicious impacts upon brain atrophy. Partly for this reason, comparing age-related brain volume trajectories between industrialized and non-industrialized populations can help to suggest lifestyle correlates of brain health. The Tsimane, indigenous to the Bolivian Amazon, derive their subsistence from foraging and horticulture and are physically active. The Moseten, a mixed-ethnicity farming population, are physically active but less than the Tsimane. Within both populations (N = 1024; age range = 46-83), we calculated regional brain volumes from computed tomography and compared their cross-sectional trends with age to those of UK Biobank (UKBB) participants (N = 19,973; same age range). Surprisingly among Tsimane and Moseten (T/M) males, some parietal and occipital structures mediating visuospatial abilities exhibit small but significant increases in regional volume with age. UKBB males exhibit a steeper negative trend of regional volume with age in frontal and temporal structures compared to T/M males. However, T/M females exhibit significantly steeper rates of brain volume decrease with age compared to UKBB females, particularly for some cerebro-cortical structures (e.g., left subparietal cortex). Across the three populations, observed trends exhibit no interhemispheric asymmetry. In conclusion, the age-related rate of regional brain volume change may differ by lifestyle and sex. The lack of brain volume reduction with age is not known to exist in other human population, highlighting the putative role of lifestyle in constraining regional brain atrophy and promoting elements of non-industrialized lifestyle like higher physical activity.

4.
Sci Adv ; 10(15): eadm7600, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38608019

RESUMO

Myelination is essential for neuronal function and health. In peripheral nerves, >100 causative mutations have been identified that cause Charcot-Marie-Tooth disease, a disorder that can affect myelin sheaths. Among these, a number of mutations are related to essential targets of the posttranslational modification neddylation, although how these lead to myelin defects is unclear. Here, we demonstrate that inhibiting neddylation leads to a notable absence of peripheral myelin and axonal loss both in developing and regenerating mouse nerves. Our data indicate that neddylation exerts a global influence on the complex transcriptional and posttranscriptional program by simultaneously regulating the expression and function of multiple essential myelination signals, including the master transcription factor EGR2 and the negative regulators c-Jun and Sox2, and inducing global secondary changes in downstream pathways, including the mTOR and YAP/TAZ signaling pathways. This places neddylation as a critical regulator of myelination and delineates the potential pathogenic mechanisms involved in CMT mutations related to neddylation.


Assuntos
Doença de Charcot-Marie-Tooth , Células de Schwann , Animais , Camundongos , Bainha de Mielina/genética , Doença de Charcot-Marie-Tooth/genética , Mutação , Processamento de Proteína Pós-Traducional
5.
Clin Anat ; 37(5): 587-601, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38566474

RESUMO

The ancient Egyptians considered the heart to be the most important organ. The belief that the heart remained in the body is widespread in the archeological and paleopathological literature. The purpose of this study was to perform an overview of the preserved intrathoracic structures and thoracic and abdominal cavity filling, and to determine the prevalence and computed tomography (CT) characteristics of the myocardium in the preserved hearts of ancient Egyptian mummies. Whole-body CT examinations of 45 ancient Egyptian mummies (23 mummies from the Ägyptisches Museum und Papyrussammlung, Berlin, Germany, and 22 mummies from the Museo Egizio, Turin, Italy) were systematically assessed for preserved intrathoracic soft tissues including various anatomical components of the heart (pericardium, interventricular septum, four chambers, myocardium, valves). Additionally, evidence of evisceration and cavity filling was documented. In cases with identifiable myocardium, quantitative (measurements of thickness and density) and qualitative (description of the structure) assessment of the myocardial tissue was carried out. Heart structure was identified in 28 mummies (62%). In 33 mummies, CT findings demonstrated evisceration, with subsequent cavity filling in all but one case. Preserved myocardium was identified in nine mummies (five male, four female) as a mostly homogeneous, shrunken structure. The posterior wall of the myocardium had a mean maximum thickness of 3.6 mm (range 1.4-6.6 mm) and a mean minimum thickness of 1.0 mm (range 0.5-1.7 mm). The mean Hounsfield units (HU) of the myocardium at the posterior wall was 61 (range, 185-305). There was a strong correlation between the HU of the posterior wall of the myocardium and the mean HU of the muscles at the dorsal humerus (R = 0.77; p = 0.02). In two cases, there were postmortem changes in the myocardium, most probably due to insect infestation. To our knowledge, this is the first study to investigate the myocardium systematically on CT scans of ancient Egyptian mummies. Strong correlations between the densities of the myocardium and skeletal muscle indicated similar postmortem changes of the respective musculature during the mummification process within individual mummies. The distinct postmortem shrinking of the myocardium and the collapse of the left ventriclular cavity in several cases did not allow for paleopathological diagnoses such as myocardial scarring.


Assuntos
Coração , Múmias , Miocárdio , Tomografia Computadorizada por Raios X , Múmias/diagnóstico por imagem , Humanos , Coração/diagnóstico por imagem , Masculino , Feminino , Adulto , Miocárdio/patologia , Antigo Egito , Pessoa de Meia-Idade , Adulto Jovem
6.
Cell Rep ; 43(3): 113924, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38507413

RESUMO

The posttranslational modification of proteins critically influences many biological processes and is a key mechanism that regulates the function of the RNA-binding protein Hu antigen R (HuR), a hub in liver cancer. Here, we show that HuR is SUMOylated in the tumor sections of patients with hepatocellular carcinoma in contrast to the surrounding tissue, as well as in human cell line and mouse models of the disease. SUMOylation of HuR promotes major cancer hallmarks, namely proliferation and invasion, whereas the absence of HuR SUMOylation results in a senescent phenotype with dysfunctional mitochondria and endoplasmic reticulum. Mechanistically, SUMOylation induces a structural rearrangement of the RNA recognition motifs that modulates HuR binding affinity to its target RNAs, further modifying the transcriptomic profile toward hepatic tumor progression. Overall, SUMOylation constitutes a mechanism of HuR regulation that could be potentially exploited as a therapeutic strategy for liver cancer.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Humanos , Camundongos , Carcinoma Hepatocelular/metabolismo , Modelos Animais de Doenças , Proteína Semelhante a ELAV 1/metabolismo , Neoplasias Hepáticas/patologia , RNA/metabolismo , Sumoilação
7.
Cell Mol Biol Lett ; 29(1): 15, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38229033

RESUMO

BACKGROUND: The eukaryotic translation initiation protein eIF5A is a highly conserved and essential factor that plays a critical role in different physiological and pathological processes including stress response and cancer. Different proteomic studies suggest that eIF5A may be a small ubiquitin-like modifier (SUMO) substrate, but whether eIF5A is indeed SUMOylated and how relevant is this modification for eIF5A activities are still unknown. METHODS: SUMOylation was evaluated using in vitro SUMOylation assays, Histidine-tagged proteins purification from His6-SUMO2 transfected cells, and isolation of endogenously SUMOylated proteins using SUMO-binding entities (SUBES). Mutants were engineered by site-directed mutagenesis. Protein stability was measured by a cycloheximide chase assay. Protein localization was determined using immunofluorescence and cellular fractionation assays. The ability of eIF5A1 constructs to complement the growth of Saccharomyces cerevisiae strains harboring thermosensitive mutants of a yeast EIF5A homolog gene (HYP2) was analyzed. The polysome profile and the formation of stress granules in cells expressing Pab1-GFP (a stress granule marker) by immunofluorescence were determined in yeast cells subjected to heat shock. Cell growth and migration of pancreatic ductal adenocarcinoma PANC-1 cells overexpressing different eIF5A1 constructs were evaluated using crystal violet staining and transwell inserts, respectively. Statistical analysis was performed with GraphPad Software, using unpaired Student's t-test, or one-way or two-way analysis of variance (ANOVA). RESULTS: We found that eIF5A is modified by SUMO2 in vitro, in transfected cells and under endogenous conditions, revealing its physiological relevance. We identified several SUMO sites in eIF5A and found that SUMOylation modulates both the stability and the localization of eIF5A in mammalian cells. Interestingly, the SUMOylation of eIF5A responds to specific stresses, indicating that it is a regulated process. SUMOylation of eIF5A is conserved in yeast, the eIF5A SUMOylation mutants are unable to completely suppress the defects of HYP2 mutants, and SUMOylation of eIF5A is important for both stress granules formation and disassembly of polysomes induced by heat-shock. Moreover, mutation of the SUMOylation sites in eIF5A abolishes its promigratory and proproliferative activities in PANC-1 cells. CONCLUSIONS: SUMO2 conjugation to eIF5A is a stress-induced response implicated in the adaptation of yeast cells to heat-shock stress and required to promote the growth and migration of pancreatic ductal adenocarcinoma cells.


Assuntos
Adenocarcinoma , Saccharomyces cerevisiae , Animais , Humanos , Mamíferos , Proteômica , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Sumoilação , Ubiquitina/metabolismo
9.
Chembiochem ; 25(6): e202300746, 2024 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-38081789

RESUMO

A complex code of cellular signals is mediated by ubiquitin and ubiquitin-like (Ub/UbL) modifications on substrate proteins. The so-called Ubiquitin Code specifies protein fates, such as stability, subcellular localization, functional activation or suppression, and interactions. Hundreds of enzymes are involved in placing and removing Ub/UbL on thousands of substrates, while the consequences of modifications and the mechanisms of specificity are still poorly defined. Challenges include rapid and transient engagement of enzymes and Ub/UbL interactors, low stoichiometry of modified versus non-modified cellular substrates, and protease-mediated loss of Ub/UbL in lysates. To decipher this complexity and confront the challenges, many tools have been created to trap and identify substrates and interactors linked to Ub/UbL modification. This review focuses on an assortment of biotin-based tools developed for this purpose (for example BioUbLs, UbL-ID, BioE3, BioID), taking advantage of the strong affinity of biotin-streptavidin and the stringent lysis/washing approach allowed by it, paired with sensitive mass-spectrometry-based proteomic methods. Knowing how substrates change during development and disease, the consequences of substrate modification, and matching substrates to particular UbL-ligating enzymes will contribute new insights into how Ub/UbL signaling works and how it can be exploited for therapies.


Assuntos
Biotina , Ubiquitina , Ubiquitina/metabolismo , Proteômica , Peptídeo Hidrolases
10.
Evol Med Public Health ; 11(1): 472-484, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38145005

RESUMO

Background: In industrialized populations, low male testosterone is associated with higher rates of cardiovascular mortality. However, coronary risk factors like obesity impact both testosterone and cardiovascular outcomes. Here, we assess the role of endogenous testosterone on coronary artery calcium in an active subsistence population with relatively low testosterone levels, low cardiovascular risk and low coronary artery calcium scores. Methodology: In this cross-sectional community-based study, 719 Tsimane forager-horticulturalists in the Bolivian Amazon aged 40+ years underwent computed tomography (49.8% male, mean age 57.6 years). Results: Coronary artery calcium levels were low; 84.5% had no coronary artery calcium. Zero-inflated negative binomial models found testosterone was positively associated with coronary artery calcium for the full sample (Incidence Rate Ratio [IRR] = 1.477, 95% Confidence Interval [CI] 1.001-2.170, P = 0.031), and in a male-only subset (IRR = 1.532, 95% CI 0.993-2.360, P = 0.053). Testosterone was also positively associated with clinically relevant coronary atherosclerosis (calcium >100 Agatston units) in the full sample (Odds Ratio [OR] = 1.984, 95% CI 1.202-3.275, P = 0.007) and when limited to male-only sample (OR = 2.032, 95% CI 1.118-4.816, P = 0.024). Individuals with coronary artery calcium >100 had 20% higher levels of testosterone than those with calcium <100 (t = -3.201, P = 0.007). Conclusions and Implications: Among Tsimane, testosterone is positively associated with coronary artery calcium despite generally low normal testosterone levels, minimal atherosclerosis and rare cardiovascular disease (CVD) events. Associations between low testosterone and CVD events in industrialized populations are likely confounded by obesity and other lifestyle factors.

11.
Nat Commun ; 14(1): 7656, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37996419

RESUMO

Hundreds of E3 ligases play a critical role in recognizing specific substrates for modification by ubiquitin (Ub). Separating genuine targets of E3s from E3-interactors remains a challenge. We present BioE3, a powerful approach for matching substrates to Ub E3 ligases of interest. Using BirA-E3 ligase fusions and bioUb, site-specific biotinylation of Ub-modified substrates of particular E3s facilitates proteomic identification. We show that BioE3 identifies both known and new targets of two RING-type E3 ligases: RNF4 (DNA damage response, PML bodies), and MIB1 (endocytosis, autophagy, centrosome dynamics). Versatile BioE3 identifies targets of an organelle-specific E3 (MARCH5) and a relatively uncharacterized E3 (RNF214). Furthermore, BioE3 works with NEDD4, a HECT-type E3, identifying new targets linked to vesicular trafficking. BioE3 detects altered specificity in response to chemicals, opening avenues for targeted protein degradation, and may be applicable for other Ub-likes (UbLs, e.g., SUMO) and E3 types. BioE3 applications shed light on cellular regulation by the complex UbL network.


Assuntos
Ubiquitina-Proteína Ligases , Ubiquitina , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina/metabolismo , Ubiquitinação , Proteômica , Proteólise
12.
Patterns (N Y) ; 4(11): 100859, 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-38035196

RESUMO

A fundamental hindrance to building data-driven reduced-order models (ROMs) is the poor topological quality of a low-dimensional data projection. This includes behavior such as overlapping, twisting, or large curvatures or uneven data density that can generate nonuniqueness and steep gradients in quantities of interest (QoIs). Here, we employ an encoder-decoder neural network architecture for dimensionality reduction. We find that nonlinear decoding of projection-dependent QoIs, when embedded in a dimensionality reduction technique, promotes improved low-dimensional representations of complex multiscale and multiphysics datasets. When data projection (encoding) is affected by forcing accurate nonlinear reconstruction of the QoIs (decoding), we minimize nonuniqueness and gradients in representing QoIs on a projection. This in turn leads to enhanced predictive accuracy of a ROM. Our findings are relevant to a variety of disciplines that develop data-driven ROMs of dynamical systems such as reacting flows, plasma physics, atmospheric physics, or computational neuroscience.

13.
Nat Commun ; 14(1): 3496, 2023 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-37311743

RESUMO

Sialic acid-binding Ig-like lectin 15 (Siglec-15) is an immune modulator and emerging cancer immunotherapy target. However, limited understanding of its structure and mechanism of action restrains the development of drug candidates that unleash its full therapeutic potential. In this study, we elucidate the crystal structure of Siglec-15 and its binding epitope via co-crystallization with an anti-Siglec-15 blocking antibody. Using saturation transfer-difference nuclear magnetic resonance (STD-NMR) spectroscopy and molecular dynamics simulations, we reveal Siglec-15 binding mode to α(2,3)- and α(2,6)-linked sialic acids and the cancer-associated sialyl-Tn (STn) glycoform. We demonstrate that binding of Siglec-15 to T cells, which lack STn expression, depends on the presence of α(2,3)- and α(2,6)-linked sialoglycans. Furthermore, we identify the leukocyte integrin CD11b as a Siglec-15 binding partner on human T cells. Collectively, our findings provide an integrated understanding of the structural features of Siglec-15 and emphasize glycosylation as a crucial factor in controlling T cell responses.


Assuntos
Integrinas , Linfócitos T , Humanos , Cristalização , Epitopos , Glicosilação
14.
Proc Natl Acad Sci U S A ; 120(13): e2205448120, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36940322

RESUMO

Little is known about brain aging or dementia in nonindustrialized environments that are similar to how humans lived throughout evolutionary history. This paper examines brain volume (BV) in middle and old age among two indigenous South American populations, the Tsimane and Moseten, whose lifestyles and environments diverge from those in high-income nations. With a sample of 1,165 individuals aged 40 to 94, we analyze population differences in cross-sectional rates of decline in BV with age. We also assess the relationships of BV with energy biomarkers and arterial disease and compare them against findings in industrialized contexts. The analyses test three hypotheses derived from an evolutionary model of brain health, which we call the embarrassment of riches (EOR). The model hypothesizes that food energy was positively associated with late life BV in the physically active, food-limited past, but excess body mass and adiposity are now associated with reduced BV in industrialized societies in middle and older ages. We find that the relationship of BV with both non-HDL cholesterol and body mass index is curvilinear, positive from the lowest values to 1.4 to 1.6 SDs above the mean, and negative from that value to the highest values. The more acculturated Moseten exhibit a steeper decrease in BV with age than Tsimane, but still shallower than US and European populations. Lastly, aortic arteriosclerosis is associated with lower BV. Complemented by findings from the United States and Europe, our results are consistent with the EOR model, with implications for interventions to improve brain health.


Assuntos
Envelhecimento , Sistema Cardiovascular , Humanos , Estados Unidos , Estudos Transversais , Encéfalo , América do Sul
15.
Alzheimers Dement ; 19(1): 44-55, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35262289

RESUMO

INTRODUCTION: We evaluated the prevalence of dementia and mild cognitive impairment (MCI) in indigenous Tsimane and Moseten, who lead a subsistence lifestyle. METHODS: Participants from population-based samples ≥ 60 years of age (n = 623) were assessed using adapted versions of the Modified Mini-Mental State Examination, informant interview, longitudinal cognitive testing and brain computed tomography (CT) scans. RESULTS: Tsimane exhibited five cases of dementia (among n = 435; crude prevalence = 1.2%, 95% confidence interval [CI]: 0.4, 2.7); Moseten exhibited one case (among n = 169; crude prevalence = 0.6%, 95% CI: 0.0, 3.2), all age ≥ 80 years. Age-standardized MCI prevalence was 7.7% (95% CI: 5.2, 10.3) in Tsimane and 9.8% (95% CI: 4.9, 14.6) in Moseten. Cognitive impairment was associated with visuospatial impairments, parkinsonian symptoms, and vascular calcification in the basal ganglia. DISCUSSION: The prevalence of dementia in this cohort is among the lowest in the world. Widespread intracranial medial arterial calcifications suggest a previously unrecognized, non-Alzheimer's disease (AD) dementia phenotype.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Demência , Humanos , Prevalência , Bolívia/epidemiologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/epidemiologia , Disfunção Cognitiva/complicações , Neuroimagem , Demência/diagnóstico por imagem , Demência/epidemiologia , Demência/complicações , Doença de Alzheimer/epidemiologia , Progressão da Doença
16.
Methods Mol Biol ; 2602: 177-189, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36446975

RESUMO

Posttranslational modifications by the ubiquitin-like family (UbL) of proteins determine the biological fate of a substrate, including new interaction partners. In the case of the small ubiquitin-like modifier (SUMO), this is achieved in part through its non-covalent interaction with SUMO-interacting motifs (SIMs) found in some proteins. Investigating such partner-complex formation is particularly challenging due to the fast dynamics and reversibility of SUMO modifications and the low affinity of SUMO-SIM interactions. Here, we present a detailed protocol of SUMO-ID, a technology that merges promiscuous proximity biotinylation by TurboID enzyme and protein-fragment complementation strategy to specifically biotinylate SUMO-dependent interactors of particular substrates. When coupled to streptavidin-affinity purification and mass spectrometry, SUMO-ID efficiently identifies SUMO-dependent interactors of a given protein. The methodology describes all the steps from SUMO-ID cell line generation to LC-MS sample preparation to study SUMO-dependent interactors of a particular protein. The protocol is generic and therefore adaptable to study other UbL-dependent interactors, such as ubiquitin.


Assuntos
Processamento de Proteína Pós-Traducional , Ubiquitina , Espectrometria de Massas , Biotinilação , Linhagem Celular
17.
J Med Internet Res ; 24(9): e33720, 2022 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-36125859

RESUMO

BACKGROUND: A Trusted Research Environment (TRE; also known as a Safe Haven) is an environment supported by trained staff and agreed processes (principles and standards), providing access to data for research while protecting patient confidentiality. Accessing sensitive data without compromising the privacy and security of the data is a complex process. OBJECTIVE: This paper presents the security measures, administrative procedures, and technical approaches adopted by TREs. METHODS: We contacted 73 TRE operators, 22 (30%) of whom, in the United Kingdom and internationally, agreed to be interviewed remotely under a nondisclosure agreement and to complete a questionnaire about their TRE. RESULTS: We observed many similar processes and standards that TREs follow to adhere to the Seven Safes principles. The security processes and TRE capabilities for supporting observational studies using classical statistical methods were mature, and the requirements were well understood. However, we identified limitations in the security measures and capabilities of TREs to support "next-generation" requirements such as wide ranges of data types, ability to develop artificial intelligence algorithms and software within the environment, handling of big data, and timely import and export of data. CONCLUSIONS: We found a lack of software or other automation tools to support the community and limited knowledge of how to meet the next-generation requirements from the research community. Disclosure control for exporting artificial intelligence algorithms and software was found to be particularly challenging, and there is a clear need for additional controls to support this capability within TREs.


Assuntos
Inteligência Artificial , Segurança Computacional , Confidencialidade , Humanos , Privacidade , Pesquisa Qualitativa
18.
Sci Rep ; 12(1): 14496, 2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-36008473

RESUMO

In reduced-order modeling, complex systems that exhibit high state-space dimensionality are described and evolved using a small number of parameters. These parameters can be obtained in a data-driven way, where a high-dimensional dataset is projected onto a lower-dimensional basis. A complex system is then restricted to states on a low-dimensional manifold where it can be efficiently modeled. While this approach brings computational benefits, obtaining a good quality of the manifold topology becomes a crucial aspect when models, such as nonlinear regression, are built on top of the manifold. Here, we present a quantitative metric for characterizing manifold topologies. Our metric pays attention to non-uniqueness and spatial gradients in physical quantities of interest, and can be applied to manifolds of arbitrary dimensionality. Using the metric as a cost function in optimization algorithms, we show that optimized low-dimensional projections can be found. We delineate a few applications of the cost function to datasets representing argon plasma, reacting flows and atmospheric pollutant dispersion. We demonstrate how the cost function can assess various dimensionality reduction and manifold learning techniques as well as data preprocessing strategies in their capacity to yield quality low-dimensional projections. We show that improved manifold topologies can facilitate building nonlinear regression models.

19.
Semin Cell Dev Biol ; 132: 109-119, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35181195

RESUMO

Post-translational modifications of cellular substrates by members of the ubiquitin (Ub) and ubiquitin-like (UbL) family are crucial for regulating protein homeostasis in organisms. The term "ubiquitin code" encapsulates how this diverse family of modifications, via adding single UbLs or different types of UbL chains, leads to specific fates for substrates. Cancer, neurodegeneration and other conditions are sometimes linked to underlying errors in this code. Studying these modifications in cells is particularly challenging since they are usually transient, scarce, and compartment-specific. Advances in the use of biotin-based methods to label modified proteins, as well as their proximally-located interactors, facilitate isolation and identification of substrates, modification sites, and the enzymes responsible for writing and erasing these modifications, as well as factors recruited as a consequence of the substrate being modified. In this review, we discuss site-specific and proximity biotinylation approaches being currently applied for studying modifications by UbLs, highlighting the pros and cons, with mention of complementary methods when possible. Future improvements may come from bioengineering and chemical biology but even now, biotin-based technology is uncovering new substrates and regulators, expanding potential therapeutic targets to manipulate the Ub code.


Assuntos
Biotina , Ubiquitina , Ubiquitina/metabolismo , Biotina/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas/metabolismo
20.
Nat Commun ; 12(1): 6671, 2021 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-34795231

RESUMO

The fast dynamics and reversibility of posttranslational modifications by the ubiquitin family pose significant challenges for research. Here we present SUMO-ID, a technology that merges proximity biotinylation by TurboID and protein-fragment complementation to find SUMO-dependent interactors of proteins of interest. We develop an optimized split-TurboID version and show SUMO interaction-dependent labelling of proteins proximal to PML and RANGAP1. SUMO-dependent interactors of PML are involved in transcription, DNA damage, stress response and SUMO modification and are highly enriched in SUMO Interacting Motifs, but may only represent a subset of the total PML proximal proteome. Likewise, SUMO-ID also allow us to identify interactors of SUMOylated SALL1, a less characterized SUMO substrate. Furthermore, using TP53 as a substrate, we identify SUMO1, SUMO2 and Ubiquitin preferential interactors. Thus, SUMO-ID is a powerful tool that allows to study the consequences of SUMO-dependent interactions, and may further unravel the complexity of the ubiquitin code.


Assuntos
Mapeamento de Interação de Proteínas/métodos , Mapas de Interação de Proteínas , Processamento de Proteína Pós-Traducional , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Sumoilação , Linhagem Celular Tumoral , Proteínas Ativadoras de GTPase/metabolismo , Células HEK293 , Humanos , Proteína da Leucemia Promielocítica/metabolismo , Ligação Proteica , Proteína SUMO-1/metabolismo , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA