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1.
Nat Commun ; 15(1): 2626, 2024 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-38521790

RESUMO

BacA is a mycobacterial ATP-binding cassette (ABC) transporter involved in the translocation of water-soluble compounds across the lipid bilayer. Whole-cell-based assays have shown that BacA imports cobalamin as well as unrelated hydrophilic compounds such as the antibiotic bleomycin and the antimicrobial peptide Bac7 into the cytoplasm. Surprisingly, there are indications that BacA also mediates the export of different antibacterial compounds, which is difficult to reconcile with the notion that ABC transporters generally operate in a strictly unidirectional manner. Here we resolve this conundrum by developing a fluorescence-based transport assay to monitor the transport of cobalamin across liposomal membranes. We find that BacA transports cobalamin in both the import and export direction. This highly unusual bidirectionality suggests that BacA is mechanistically distinct from other ABC transporters and facilitates ATP-driven diffusion, a function that may be important for the evolvability of specific transporters, and may bring competitive advantages to microbial communities.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Vitamina B 12 , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Bicamadas Lipídicas , Trifosfato de Adenosina , Transporte Biológico
2.
Artigo em Inglês | MEDLINE | ID: mdl-38522903

RESUMO

BACKGROUND: Perfluorooctanoic acid (PFOA) is one of the major per- and polyfluoroalkyl substances. The role of ATP-binding cassette (ABC) transporters in PFOA toxicokinetics is unknown. METHODS: In this study, two ABC transporters, ABCB1 and ABCB4, were examined in mice with single intravenous PFOA administration (3.13 µmol/kg). To identify candidate renal PFOA transporters, we used a microarray approach to evaluate changes in gene expression of various kidney transporters in Abcb4 null mice. RESULTS: Biliary PFOA concentrations were lower in Abcb4 null mice (mean ± standard deviation: 0.25 ± 0.12 µg/mL) than in wild-type mice (0.87 ± 0.02 µg/mL). Immunohistochemically, ABCB4 expression was confirmed at the apical region of hepatocytes. However, renal clearance of PFOA was higher in Abcb4 null mice than in wild-type mice. Among 642 solute carrier and ABC transporters, 5 transporters showed significant differences in expression between wild-type and Abcb4 null mice. These candidates included two major xenobiotic transporters, multidrug resistance 1 (Abcb1) and organic anion transporter 3 (Slc22a8). Abcb1 mRNA levels were higher in Abcb4 null mice than in wild-type mice in kidney. In Abcb4 null mice, Abcb1b expression was enhanced in proximal tubules immunohistochemically, while that of Slc22a8 was not. Finally, in Abcb1a/b null mice, there was a significant decrease in the renal clearance of PFOA (0.69 ± 0.21 vs 1.1 mL ± 0.37/72 h in wild-type mice). A homology search of ABCB1 showed that several amino acids are mutated in humans compared with those in rodents and monkeys. CONCLUSIONS: These findings suggest that, in the mouse, Abcb4 and Abcb1 are excretory transporters of PFOA into bile and urine, respectively.


Assuntos
Caprilatos , Fluorocarbonos , Eliminação Hepatobiliar , Humanos , Camundongos , Animais , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Fluorocarbonos/toxicidade , Fluorocarbonos/metabolismo , Rim , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo
3.
Science ; 383(6689): eadj4591, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38513023

RESUMO

Brassinosteroids are steroidal phytohormones that regulate plant development and physiology, including adaptation to environmental stresses. Brassinosteroids are synthesized in the cell interior but bind receptors at the cell surface, necessitating a yet to be identified export mechanism. Here, we show that a member of the ATP-binding cassette (ABC) transporter superfamily, ABCB19, functions as a brassinosteroid exporter. We present its structure in both the substrate-unbound and the brassinosteroid-bound states. Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. In Arabidopsis thaliana, ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses. Our results uncover an elusive export mechanism for bioactive brassinosteroids that is tightly coordinated with brassinosteroid signaling.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Proteínas de Arabidopsis , Arabidopsis , Brassinosteroides , Trifosfato de Adenosina/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Brassinosteroides/metabolismo , Ácidos Indolacéticos/metabolismo , Conformação Proteica
4.
Nat Commun ; 15(1): 2389, 2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38493146

RESUMO

Yeast Cadmium Factor 1 (Ycf1) sequesters glutathione and glutathione-heavy metal conjugates into yeast vacuoles as a cellular detoxification mechanism. Ycf1 belongs to the C subfamily of ATP Binding Cassette (ABC) transporters characterized by long flexible linkers, notably the regulatory domain (R-domain). R-domain phosphorylation is necessary for activity, whereas dephosphorylation induces autoinhibition through an undefined mechanism. Because of its transient and dynamic nature, no structure of the dephosphorylated Ycf1 exists, limiting understanding of this R-domain regulation. Here, we capture the dephosphorylated Ycf1 using cryo-EM and show that the unphosphorylated R-domain indeed forms an ordered structure with an unexpected hairpin topology bound within the Ycf1 substrate cavity. This architecture and binding mode resemble that of a viral peptide inhibitor of an ABC transporter and the secreted bacterial WXG peptide toxins. We further reveal the subset of phosphorylation sites within the hairpin turn that drive the reorganization of the R-domain conformation, suggesting a mechanism for Ycf1 activation by phosphorylation-dependent release of R-domain mediated autoinhibition.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Cádmio/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Glutationa/metabolismo , Peptídeos/metabolismo
5.
Sci Adv ; 10(12): eadk8521, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38507491

RESUMO

The type I adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter DppABCD is believed to be responsible for the import of exogenous heme as an iron source into the cytoplasm of the human pathogen Mycobacterium tuberculosis (Mtb). Additionally, this system is also known to be involved in the acquisition of tri- or tetra-peptides. Here, we report the cryo-electron microscopy structures of the dual-function Mtb DppABCD transporter in three forms, namely, the apo, substrate-bound, and ATP-bound states. The apo structure reveals an unexpected and previously uncharacterized assembly mode for ABC importers, where the lipoprotein DppA, a cluster C substrate-binding protein (SBP), stands upright on the translocator DppBCD primarily through its hinge region and N-lobe. These structural data, along with biochemical studies, reveal the assembly of DppABCD complex and the detailed mechanism of DppABCD-mediated transport. Together, these findings provide a molecular roadmap for understanding the transport mechanism of a cluster C SBP and its translocator.


Assuntos
Mycobacterium tuberculosis , Humanos , Mycobacterium tuberculosis/metabolismo , Microscopia Crioeletrônica , Proteínas de Bactérias/metabolismo , Transportadores de Cassetes de Ligação de ATP/química , Trifosfato de Adenosina/metabolismo
6.
Proc Natl Acad Sci U S A ; 121(11): e2309841121, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38442151

RESUMO

The transporter associated with antigen processing (TAP) is a key player in the major histocompatibility class I-restricted antigen presentation and an attractive target for immune evasion by viruses. Bovine herpesvirus 1 impairs TAP-dependent antigenic peptide transport through a two-pronged mechanism in which binding of the UL49.5 gene product to TAP both inhibits peptide transport and triggers its proteasomal degradation. How UL49.5 promotes TAP degradation has, so far, remained unknown. Here, we use high-content siRNA and genome-wide CRISPR-Cas9 screening to identify CLR2KLHDC3 as the E3 ligase responsible for UL49.5-triggered TAP disposal. We propose that the C terminus of UL49.5 mimics a C-end rule degron that recruits the E3 to TAP and engages the cullin-RING E3 ligase in endoplasmic reticulum-associated degradation.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Herpesviridae , Apresentação de Antígeno , Citomegalovirus , Degradação Associada com o Retículo Endoplasmático , Proteínas de Membrana Transportadoras , Peptídeos , Ubiquitina-Proteína Ligases/genética , Herpesviridae/fisiologia
7.
Theor Appl Genet ; 137(3): 63, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38427048

RESUMO

KEY MESSAGE: The gene BrABCG26 responsible for male sterility of Chinese cabbage was confirmed by two allelic mutants. Male-sterile lines are an important way of heterosis utilization in Chinese cabbage. In this study, two allelic male-sterile mutants msm3-1 and msm3-2 were obtained from a Chinese cabbage double haploid (DH) line 'FT' by using EMS-mutagenesis. Compared to the wild-type 'FT,' the stamens of mutants were completely degenerated and had no pollen, and other characters had no obvious differences. Cytological observation revealed that the failure of vacuolation of the mononuclear microspore, accompanied by abnormal tapetal degradation, resulted in anther abortion in mutants. Genetic analysis showed that a recessive gene controlled the mutant trait. MutMap combined with kompetitive allele specific PCR genotyping analyses showed that BraA01g038270.3C, encoding a transporter ABCG26 that played a vital role in pollen wall formation, was the candidate gene for msm3-1, named BrABCG26. Compared with wild-type 'FT,' the mutations existed on the second exon (C to T) and the sixth exon (C to T) of BrABCG26 gene in mutants msm3-1 and msm3-2, leading to the loss-of-function truncated protein, which verified the BrABCG26 function in stamen development. Subcellular localization and expression pattern analysis indicated that BrABCG26 was localized in the nucleus and was expressed in all organs, with the highest expression in flower buds. Compared to the wild-type 'FT,' the expressions of BrABCG26 were significantly reduced in flower buds and anthers of mutants. Promoter activity analysis showed that a strong GUS signal was detected in flower buds. These results indicated that BrABCG26 is responsible for the male sterility of msm3 mutants in Chinese cabbage.


Assuntos
Brassica rapa , Brassica , Infertilidade Masculina , Masculino , Humanos , Brassica rapa/genética , Perfilação da Expressão Gênica/métodos , Transportadores de Cassetes de Ligação de ATP/genética , Proteínas de Plantas/genética , Brassica/genética , Mutação , Regulação da Expressão Gênica de Plantas , Infertilidade das Plantas/genética
8.
Int J Biol Macromol ; 262(Pt 2): 129984, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38342260

RESUMO

The ATP-binding cassette (ABC) transporters have crucial roles in various biological processes such as growth, development and immune defense in eukaryotes. However, the roles of ABC transporters in the immune system of crustaceans remain elusive. In this study, 38 ABC genes were systematically identified and characterized in Penaeus vannamei. Bioinformation analysis revealed that PvABC genes were categorized into ABC A-H eight subfamilies with 17 full-transporters, 11 half transporters and 10 soluble proteins, and multiple immunity-related cis-elements were found in gene promoter regions. Expression analysis showed that most PvABC genes were widely and highly expressed in immune-related tissues and responded to the stimulation of Vibrio parahaemolyticus. To investigate whether PvABC genes mediated innate immunity, PvABCC5, PvABCF1 and PvABCB4 were selected for dsRNA interference experiment. Knockdown of PvABCF1 and PvABCC5 not PvABCB4 increased the cumulative mortality of P. vannamei and bacterial loads in hepatopancreas after infection with V. parahaemolyticus. Further analysis showed that the PvABCF1 and PvABCC5 knockdown decreased expression levels of NF-κB pathway genes and antimicrobial peptides (AMPs). Collectively, these findings indicated that PvABCF1 and PvABCC5 might restrict V. parahaemolyticus challenge by positively regulating NF-κB pathway and then promoting the expression of AMPs, which would contribute to overall understand the function of ABC genes in innate immunity of invertebrates.


Assuntos
Penaeidae , Vibrio parahaemolyticus , Animais , NF-kappa B/genética , NF-kappa B/metabolismo , Vibrio parahaemolyticus/genética , Penaeidae/genética , Penaeidae/microbiologia , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Artrópodes/genética , Transdução de Sinais , Imunidade Inata/genética , Trifosfato de Adenosina/metabolismo
9.
Chem Biol Drug Des ; 103(2): e14490, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38388887

RESUMO

Resistance to 5-fluorouracil (5-FU) is still a primary setback to the success of colorectal cancer (CRC) chemotherapy. Transmembrane protein 97 (TMEM97) functions as an oncogene in CRC. However, the role and mechanism of TMEM97 in regulating 5-FU resistance in CRC cells remains unclear. TMEM97 expression in CRC samples was analyzed by GEPIA and human protein atlas (HPA) databases. TMEM97, E-cadherin, Vimentin, N-cadherin, P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1)/ABCC1, ABCC2, and the changes of protein kinase B/mammalian target of rapamycin (mTOR) pathway were explored by western blot analysis. IC50 value for 5-FU and cell viability was examined by MTT assay. Apoptosis was evaluated by flow cytometry. TMEM97 was highly expressed in colon adenocarcinoma (COAD) and rectum adenocarcinoma (READ) based on GEPIA and HPA databases. TMEM97 knockdown attenuated 5-FU resistance in HCT116/R and SW480/R cells, as evidenced by the reduced IC50 value for 5-FU and the increased apoptosis. TMEM97 knockdown suppressed epithelial-mesenchymal transition (EMT), expression of ATP-binding cassette (ABC) transporters, and the Akt/mTOR pathway. Mechanistically, activation of Akt/mTOR pathway abolished the inhibitory effects of TMEM97 knockdown on 5-FU resistance, EMT, and ABC transporter expression. In conclusion, TMEM97 knockdown inhibited 5-FU resistance in CRC by regulating EMT and ABC transporter expression via inactivating the Akt/mTOR pathway.


Assuntos
Adenocarcinoma , Neoplasias do Colo , Neoplasias Colorretais , Humanos , Fluoruracila/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias do Colo/tratamento farmacológico , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adenocarcinoma/tratamento farmacológico , Neoplasias Colorretais/tratamento farmacológico , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Serina-Treonina Quinases TOR/metabolismo , Transição Epitelial-Mesenquimal , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo
10.
Stem Cell Res ; 76: 103364, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38422817

RESUMO

The ATP-binding cassette, subfamily A (ABC1), member 7 (ABCA7) gene is associated with Alzheimer's disease (AD) risk in populations of African, Asian, and European ancestry1-5. Numerous ABCA7 mutations contributing to risk have been identified, including a 44 base pair deletion (rs142076058) specific to individuals of African ancestry and predicted to cause a frameshift mutation (p.Arg578Alafs) (Cukier et al., 2016). The UMi043-A human induced pluripotent stem cell line was derived from an African American individual with AD who is heterozygous for this deletion and is a resource to further investigate ABCA7 and how this African-specific deletion may influence disease pathology.


Assuntos
Doença de Alzheimer , Linhagem Celular , Células-Tronco Pluripotentes Induzidas , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Negro ou Afro-Americano/genética , Células-Tronco Pluripotentes Induzidas/citologia , Mutação
11.
Biochem Pharmacol ; 222: 116096, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38423188

RESUMO

Calcium channel blockers (CCBs) are commonly used as antihypertensive agents. While certain L-type CCBs exhibit antiatherogenic effects, the impact of Cav3.1 T-type CCBs on antiatherogenesis and lipid metabolism remains unexplored. NNC 55-0396 (NNC) is a highly selective blocker of T-type calcium channels (Cav3.1 channels). We investigated the effects of NNC on relevant molecules and molecular mechanisms in human THP-1 macrophages. Cholesterol efflux, an indicator of reverse cholesterol transport (RCT) efficiency, was assessed using [3H]-labeled cholesterol. In vivo, high cholesterol diet (HCD)-fed LDL receptor knockout (Ldlr-/-) mice, an atherosclerosis-prone model, underwent histochemical staining to analyze plaque burden. Treatment of THP-1 macrophages with NNC facilitated cholesterol efflux and reduced intracellular cholesterol accumulation. Pharmacological and genetic interventions demonstrated that NNC treatment or Cav3.1 knockdown significantly enhanced the protein expression of scavenger receptor B1 (SR-B1), ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and liver X receptor alpha (LXRα) transcription factor. Mechanistic analysis revealed that NNC activates p38 and c-Jun N-terminal kinase (JNK) phosphorylation, leading to increased expression of ABCA1, ABCG1, and LXRα-without involving the microRNA pathway. LXRα isrequired for NNC-induced ABCA1 and ABCG1 expression. Administering NNC diminished atherosclerotic lesion area and lipid deposition in HCD-fed Ldlr-/- mice. NNC's anti-atherosclerotic effects, achieved through enhanced cholesterol efflux and inhibition of lipid accumulation, suggest a promising therapeutic approach for hypertensive patients with atherosclerosis. This research highlights the potential of Cav3.1 T-type CCBs in addressing cardiovascular complications associated with hypertension.


Assuntos
Aterosclerose , Benzimidazóis , Ciclopropanos , Hipercolesterolemia , Naftalenos , Humanos , Animais , Camundongos , Bloqueadores dos Canais de Cálcio/farmacologia , Bloqueadores dos Canais de Cálcio/uso terapêutico , Aterosclerose/tratamento farmacológico , Aterosclerose/prevenção & controle , Aterosclerose/metabolismo , Receptores X do Fígado/metabolismo , Colesterol/metabolismo , Hipercolesterolemia/tratamento farmacológico , Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo
12.
Drug Resist Updat ; 73: 101066, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38387283

RESUMO

ABCG2 is an important ATP-binding cassette transporter impacting the absorption and distribution of over 200 chemical toxins and drugs. ABCG2 also reduces the cellular accumulation of diverse chemotherapeutic agents. Acquired somatic mutations in the phylogenetically conserved amino acids of ABCG2 might provide unique insights into its molecular mechanisms of transport. Here, we identify a tumor-derived somatic mutation (Q393K) that occurs in a highly conserved amino acid across mammalian species. This ABCG2 mutant seems incapable of providing ABCG2-mediated drug resistance. This was perplexing because it is localized properly and retained interaction with substrates and nucleotides. Using a conformationally sensitive antibody, we show that this mutant appears "locked" in a non-functional conformation. Structural modeling and molecular dynamics simulations based on ABCG2 cryo-EM structures suggested that the Q393K interacts with the E446 to create a strong salt bridge. The salt bridge is proposed to stabilize the inward-facing conformation, resulting in an impaired transporter that lacks the flexibility to readily change conformation, thereby disrupting the necessary communication between substrate binding and transport.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Neoplasias , Humanos , Animais , Transportadores de Cassetes de Ligação de ATP/metabolismo , Mutação , Resistência a Medicamentos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Resistencia a Medicamentos Antineoplásicos/genética , Mamíferos/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo
13.
Microbiology (Reading) ; 170(2)2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38334478

RESUMO

YejABEF is an ATP-binding cassette transporter that is implicated in the sensitivity of Escherichia coli to anti-microbial peptides, the best-characterized example being microcin C, a peptide-nucleotide antibiotic that targets aspartyl-tRNA synthetase. Here the structure of the extracellular solute binding protein, YejA, has been determined, revealing an oligopeptide-binding protein fold enclosing a ligand-binding pocket larger than those of other peptide-binding proteins of known structure. Prominent electron density in this cavity defines an undecapeptide sequence LGEPRYAFNFN, an observation that is confirmed by mass spectrometry. In the structure, the peptide interactions with the protein are mediated by main chain hydrogen bonds with the exception of Arg5 whose guanidinium side chain makes a set of defining polar interactions with four YejA residues. More detailed characterization of purified recombinant YejA, by a combination of ESI and MALDI-mass spectrometry as well as thermal shift assays, reveals a set of YejA complexes containing overlapping peptides 10-19 residues in length. All contain the sequence LGEPRYAFN. Curiously, these peptides correspond to residues 8-26 of the mature YejA protein, which belong to a unique N-terminal extension that distinguishes YejA from other cluster C oligopeptide binding proteins of known structure. This 35-residue extension is well-ordered and packs across the surface of the protein. The undecapeptide ligand occupies only a fraction of the enclosed pocket volume suggesting the possibility that much larger peptides or peptide conjugates could be accommodated, though thermal shift assays of YejA binding to antimicrobial peptides and peptides unrelated to LGEPRYAFNFN have not provided evidence of binding. While the physiological significance of this 'auto-binding' is not clear, the experimental data suggest that it is not an artefact of the crystallization process and that it may have a function in the sensing of periplasmic or membrane stress.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Proteínas de Membrana Transportadoras , Peptídeos , Ligantes , Peptídeos/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Oligopeptídeos , Escherichia coli/metabolismo , Ligação Proteica
14.
BMC Ophthalmol ; 24(1): 60, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347443

RESUMO

BACKGROUND: Inherited retinal dystrophies are hereditary diseases which have in common the progressive degeneration of photoreceptors. They are a group of diseases with clinical, genetic, and allelic heterogeneity. There is limited information regarding the genetic landscape of inherited retinal diseases in Mexico, therefore, the present study was conducted in the northeast region of the country. METHODS: Patients with inherited retinal dystrophies were included. A complete history, full ophthalmological and medical genetics evaluations, and genetic analysis through a targeted NGS panel for inherited retinal dystrophies comprising at least 293 genes were undertaken. RESULTS: A total of 126 patients were included. Cases were solved in 74.6% of the study's population. Retinitis pigmentosa accounted for the most found inherited retinal disease. Ninety-nine causal variants were found, being USH2A and ABCA4 the most affected genes (26 and 15 cases, respectively). CONCLUSIONS: The present study documents the most prevalent causative genes in IRDs, as USH2A, in northeastern Mexico. This contrasts with previous reports of IRDs in other zones of the country. Further studies, targeting previously unstudied populations in Mexico are important to document the genetic background of inherited retinal dystrophies in the country.


Assuntos
Distrofias Retinianas , Retinite Pigmentosa , Síndromes de Usher , Humanos , Mutação , México/epidemiologia , Distrofias Retinianas/epidemiologia , Distrofias Retinianas/genética , Retinite Pigmentosa/genética , Linhagem , Transportadores de Cassetes de Ligação de ATP/genética
15.
BMC Genomics ; 25(1): 169, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347517

RESUMO

BACKGROUND: ATP-binding cassette (ABC) transporter proteins constitute a plant gene superfamily crucial for growth, development, and responses to environmental stresses. Despite their identification in various plants like maize, rice, and Arabidopsis, little is known about the information on ABC transporters in pear. To investigate the functions of ABC transporters in pear development and abiotic stress response, we conducted an extensive analysis of ABC gene family in the pear genome. RESULTS: In this study, 177 ABC transporter genes were successfully identified in the pear genome, classified into seven subfamilies: 8 ABCAs, 40 ABCBs, 24 ABCCs, 8 ABCDs, 9 ABCEs, 8 ABCFs, and 80 ABCGs. Ten motifs were common among all ABC transporter proteins, while distinct motif structures were observed for each subfamily. Distribution analysis revealed 85 PbrABC transporter genes across 17 chromosomes, driven primarily by WGD and dispersed duplication. Cis-regulatory element analysis of PbrABC promoters indicated associations with phytohormones and stress responses. Tissue-specific expression profiles demonstrated varied expression levels across tissues, suggesting diverse functions in development. Furthermore, several PbrABC genes responded to abiotic stresses, with 82 genes sensitive to salt stress, including 40 upregulated and 23 downregulated genes. Additionally, 91 genes were responsive to drought stress, with 22 upregulated and 36 downregulated genes. These findings highlight the pivotal role of PbrABC genes in abiotic stress responses. CONCLUSION: This study provides evolutionary insights into PbrABC transporter genes, establishing a foundation for future research on their functions in pear. The identified motifs, distribution patterns, and stress-responsive expressions contribute to understanding the regulatory mechanisms of ABC transporters in pear. The observed tissue-specific expression profiles suggest diverse roles in developmental processes. Notably, the significant responses to salt and drought stress emphasize the importance of PbrABC genes in mediating adaptive responses. Overall, our study advances the understanding of PbrABC transporter genes in pear, opening avenues for further investigations in plant molecular biology and stress physiology.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Pyrus , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Pyrus/genética , Proteínas de Membrana Transportadoras/genética , Estresse Fisiológico/genética , Trifosfato de Adenosina , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Família Multigênica , Regulação da Expressão Gênica de Plantas
16.
Sci Rep ; 14(1): 3594, 2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38351313

RESUMO

Fungal pathogens are considered as serious factors for deadly diseases and are a case of medical concern. Invasive fungal infections also complicate the clinical course of COVID-19, leading to a significant increase in mortality. Furthermore, fungal strains' multidrug resistance has increased the demand for antifungals with a different mechanism of action. The present study aimed to identify antifungal compounds targeting yeast topoisomerase II (yTOPOII) derived from well-known human topoisomerase II (hTOPOII) poisons C-1305 and C-1311. Two sets of derivatives: triazoloacridinones (IKE1-8) and imidazoacridinones (IKE9-14) were synthetized and evaluated with a specific emphasis on the molecular mechanism of action. Our results indicated that their effectiveness as enzyme inhibitors was not solely due to intercalation ability but also as a result of influence on catalytic activity by the formation of covalent complexes between plasmid DNA and yTOPOII. Lysine conjunction increased the strength of the compound's interaction with DNA and improved penetration into the fungal cells. Triazoloacridinone derivatives in contrast to starting compound C-1305 exhibited moderate antifungal activity and at least twice lower cytotoxicity. Importantly, compounds (IKE5-8) were not substrates for multidrug ABC transporters whereas a derivative conjugated with lysine (IKE7), showed the ability to overcome C. glabrata fluconazole-resistance (MIC 32-64 µg mL-1).


Assuntos
Antifúngicos , Lisina , Humanos , Antifúngicos/farmacologia , Fluconazol/farmacologia , Transportadores de Cassetes de Ligação de ATP , Candida glabrata , DNA , Testes de Sensibilidade Microbiana
17.
ACS Synth Biol ; 13(2): 590-597, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38324606

RESUMO

Pleiotropic drug resistance (PDR) family proteins have been extensively studied for their roles in transporting hydrophobic substances, including carotenoids. Overexpression of the PDR family regulator Pdr3p was recently found to boost the biosynthesis of carotenoids, which could not be explained by enhanced product secretion due to the meager extracellular proportions. To provide insights into the possible mechanism, comparative transcriptomics, reverse metabolic engineering, and electrophoretic mobility shift assay (EMSA) were conducted. Transcriptomic data suggested an unexpected correlation between Pdr3p overexpression and the transcriptional levels of GAL promoter-driven genes. This assumption was verified using mCherry and the lycopene synthetic pathway as the reporters. qRT-PCR and EMSA provided further evidence for the activation of GAL promoters by Pdr3p binding to their upstream activation sequences (UASs). This work gives insight into the mechanism of Pdr3p-promoted carotenoid production and highlights the complicated metabolic networking between transcriptional factors and promoters in yeast.


Assuntos
Proteínas de Saccharomyces cerevisiae , Fatores de Transcrição , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Ligação a DNA/metabolismo , Transativadores/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética
18.
Medicina (Kaunas) ; 60(2)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38399488

RESUMO

Drug resistance remains one of the main causes of poor outcome in cancer therapy. It is also becoming evident that drug resistance to both chemotherapy and to antibiotics is driven by more than one mechanism. So far, there are at least eight recognized mechanisms behind such resistance. In this review, we choose to discuss one of these mechanisms, which is known to be partially driven by a class of transmembrane proteins known as ATP-binding cassette (ABC) transporters. In normal tissues, ABC transporters protect the cells from the toxic effects of xenobiotics, whereas in tumor cells, they reduce the intracellular concentrations of anticancer drugs, which ultimately leads to the emergence of multidrug resistance (MDR). A deeper understanding of the structures and the biology of these proteins is central to current efforts to circumvent resistance to both chemotherapy, targeted therapy, and antibiotics. Understanding the biology and the function of these proteins requires detailed structural and conformational information for this class of membrane proteins. For many years, such structural information has been mainly provided by X-ray crystallography and cryo-electron microscopy. More recently, mass spectrometry-based methods assumed an important role in the area of structural and conformational characterization of this class of proteins. The contribution of this technique to structural biology has been enhanced by its combination with liquid chromatography and ion mobility, as well as more refined labelling protocols and the use of more efficient fragmentation methods, which allow the detection and localization of labile post-translational modifications. In this review, we discuss the contribution of mass spectrometry to efforts to characterize some members of the ATP-binding cassette (ABC) proteins and why such a contribution is relevant to efforts to clarify the link between the overexpression of these proteins and the most widespread mechanism of chemoresistance.


Assuntos
Antineoplásicos , Neoplasias , Humanos , Resistencia a Medicamentos Antineoplásicos , Microscopia Crioeletrônica , Proteínas de Neoplasias , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Antineoplásicos/uso terapêutico , Antineoplásicos/farmacologia , Transportadores de Cassetes de Ligação de ATP , Antibacterianos/uso terapêutico , Trifosfato de Adenosina/farmacologia , Trifosfato de Adenosina/uso terapêutico , Neoplasias/tratamento farmacológico
19.
Proc Natl Acad Sci U S A ; 121(8): e2314437121, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38349882

RESUMO

Protein synthesis is performed by the ribosome and a host of highly conserved elongation factors. Elongation factor P (EF-P) prevents ribosome stalling at difficult-to-translate sequences, such as polyproline tracts. In bacteria, phenotypes associated with efp deletion range from modest to lethal, suggesting that some species encode an additional translation factor that has similar function to EF-P. Here we identify YfmR as a translation factor that is essential in the absence of EF-P in Bacillus subtilis. YfmR is an ABCF ATPase that is closely related to both Uup and EttA, ABCFs that bind the ribosomal E-site and are conserved in more than 50% of bacterial genomes. We show that YfmR associates with actively translating ribosomes and that depleting YfmR from Δefp cells causes severe ribosome stalling at a polyproline tract in vivo. YfmR depletion from Δefp cells was lethal and caused reduced levels of actively translating ribosomes. Our results therefore identify YfmR as an important translation factor that is essential in B. subtilis in the absence of EF-P.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/genética , Fatores de Alongamento de Peptídeos/genética , Fatores de Alongamento de Peptídeos/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Biossíntese de Proteínas , Morte Celular , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Escherichia coli/metabolismo
20.
Arch Biochem Biophys ; 753: 109915, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38307314

RESUMO

The human ATP-binding cassette (ABC) transporter, ABCG2, is responsible for multidrug resistance in some tumours. Detailed knowledge of its activity is crucial for understanding drug transport and resistance in cancer, and has implications for wider pharmacokinetics. The binding of substrates and inhibitors is a key stage in the transport cycle of ABCG2. Here, we describe a novel binding assay using a high affinity fluorescent inhibitor based on Ko143 and time-resolved Förster resonance energy transfer (TR-FRET) to measure saturation binding to ABCG2. This binding is displaced by Ko143 and other known ABCG2 ligands, and is sensitive to the addition of AMP-PNP, a non-hydrolysable ATP analogue. This assay complements the arsenal of methods for determining drug:ABCG2 interactions and has the possibility of being adaptable for other multidrug pumps.


Assuntos
Transferência Ressonante de Energia de Fluorescência , Neoplasias , Humanos , Resistencia a Medicamentos Antineoplásicos , Transportadores de Cassetes de Ligação de ATP/metabolismo , Resistência a Múltiplos Medicamentos , Trifosfato de Adenosina , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Neoplasias/metabolismo
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