scholarly journals The Role of fnx1, a Fission Yeast Multidrug Resistance Protein, in the Transition of Cells to a Quiescent G0 State

1998 ◽  
Vol 18 (9) ◽  
pp. 5239-5246 ◽  
Author(s):  
Krassen Dimitrov ◽  
Shelley Sazer
Keyword(s):  
Multidrug Resistance ◽  
Molecular Mechanisms ◽  
Morphological Changes ◽  
Sequence Similarity ◽  
Cell Communication ◽  
Major Facilitator Superfamily ◽  
Natural Habitats ◽  
Resistance Protein ◽  
Major Facilitator

ABSTRACT Most microorganisms live in conditions of nutrient limitation in their natural habitats. When exposed to these conditions they respond with physiological and morphological changes that enable them to survive. To obtain insights into the molecular mechanisms of this response a systematic genetic screen was performed to identify genes that when overexpressed can induce a starvation-like response in the yeast species Schizosaccharomyces pombe. One gene that meets these criteria, fnx1 +, induces, transcriptionally correlates with, and is required for the entry into the quiescent G0 state that is normally induced by nitrogen starvation. fnx1 + encodes a protein with sequence similarity to the proton-driven plasma membrane transporters from the multidrug resistance group of the major facilitator superfamily of proteins. We propose that fnx1 +plays a role in the entry into G0, possibly by facilitating the release of a signaling substance into the environment as a means of cell-to-cell communication.

scholarly journals Identification and Characterization of hmr19 Gene Encoding a Multidrug Resistance Efflux Protein from Streptomyces hygroscopicus subsp. yingchengensis Strain 10–22

2004 ◽  
Vol 36 (8) ◽  
pp. 519-528 ◽  
Author(s):  
Lei Qin ◽  
Heng-An Wang ◽  
Zhong-Qin Wu ◽  
Xiao-Feng Zhang ◽  
Mei-Lei Jin ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Type Strain ◽  
Wild Type Strain ◽  
Sequence Similarity ◽  
Gene Replacement ◽  
Major Facilitator Superfamily ◽  
Streptomyces Hygroscopicus ◽  
Wild Type ◽  
Gene Encoding ◽  
Major Facilitator

Abstract The hmr19 gene was cloned from Streptomyces hygroscopicus subsp. yingchengensis strain 10–22, a bacterium strain producing agricultural antibiotics. Sequence similarity comparison indicates that hmr19 gene may encode a predicted protein with 14 putative transmembrane α-helical spanners, belonging to the drug:H+ antiporter-2 family of the major facilitator superfamily. The expression of hmr19 in the mycelium of strain 10-22 was detected by Western blotting analysis. Gene replacement technology was employed to construct an hmr19 disruption mutant. The growth inhibition test against different antibiotics indicated that the mutant strain was 5–20 fold more susceptible to tetracycline, vancomycin and mitomycin C than the parental wild type strain. The mutant took up tetracycline much faster and accumulated more antibiotics than the wild type strain 10-22. While with the addition of an energy uncoupler, carbonyl cyanide m-chlorophenylhydrazone, the characteristics of the accumulation of [3H]tetracycline in these two strains were almost the same. It was thus concluded that hmr19 encoded a multidrug resistance efflux protein.

scholarly journals The Role of Several Multidrug Resistance Systems in Erwinia chrysanthemi Pathogenesis

2006 ◽  
Vol 19 (6) ◽  
pp. 607-613 ◽  
Author(s):  
Alfredo Maggiorani Valecillos ◽  
Pablo Rodríguez Palenzuela ◽  
Emilia López-Solanilla
Keyword(s):  
Multidrug Resistance ◽  
Major Facilitator Superfamily ◽  
Erwinia Chrysanthemi ◽  
Toxic Substances ◽  
Potato Protein ◽  
Mutant Strains ◽  
Genes Encoding ◽  
Major Facilitator ◽  
Tuber Extract

The role of several multidrug resistance (MDR) systems in the pathogenicity of Erwinia chrysanthemi 3937 was analyzed. Using the blast algorithm, we have identified several MDR systems in the E. chrysanthemi genome and selected two acridine resistance (Acr)-like systems, two Emr-like systems, and one member of the major facilitator superfamily family to characterize. We generated mutants in genes encoding for these systems and analyzed the virulence of the mutant strains in different hosts and their susceptibility to antibiotics, detergents, dyes, and plant compounds. We have observed that the mutant strains are differentially affected in their virulence in different hosts and that the susceptibility to toxic substances is also differential. Both Acr systems seem to be implicated in the resistance to the plant antimicrobial peptide thionin. Similarly, the emr1AB mutant is unable to grow in the presence of the potato protein tuber extract and shows a decreased virulence in this tissue. These results indicate that the function of these systems in plants could be related to the specificity to extrude a toxic compound that is present in a given host.

scholarly journals Single-Cell Transcriptomic Analysis Revealed a Critical Role of SPP1/CD44-Mediated Crosstalk Between Macrophages and Cancer Cells in Glioma

2021 ◽  
Vol 9 ◽  
Author(s):  
Cong He ◽  
Luoyan Sheng ◽  
Deshen Pan ◽  
Shuai Jiang ◽  
Li Ding ◽  
...  
Keyword(s):  
Single Cell ◽  
Tumor Heterogeneity ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Cell Communication ◽  
High Grade Glioma ◽  
Sequencing Analysis ◽  
High Grade ◽  
Cellular Components

High-grade glioma is one of the most lethal human cancers characterized by extensive tumor heterogeneity. In order to identify cellular and molecular mechanisms that drive tumor heterogeneity of this lethal disease, we performed single-cell RNA sequencing analysis of one high-grade glioma. Accordingly, we analyzed the individual cellular components in the ecosystem of this tumor. We found that tumor-associated macrophages are predominant in the immune microenvironment. Furthermore, we identified five distinct subpopulations of tumor cells, including one cycling, two OPC/NPC-like and two MES-like cell subpopulations. Moreover, we revealed the evolutionary transition from the cycling to OPC/NPC-like and MES-like cells by trajectory analysis. Importantly, we found that SPP1/CD44 interaction plays a critical role in macrophage-mediated activation of MES-like cells by exploring the cell-cell communication among all cellular components in the tumor ecosystem. Finally, we showed that high expression levels of both SPP1 and CD44 correlate with an increased infiltration of macrophages and poor prognosis of glioma patients. Taken together, this study provided a single-cell atlas of one high-grade glioma and revealed a critical role of macrophage-mediated SPP1/CD44 signaling in glioma progression, indicating that the SPP1/CD44 axis is a potential target for glioma treatment.

Insights in the molecular mechanisms of an azole stress adapted laboratory-generated Aspergillus fumigatus strain

2021 ◽  
Author(s):  
Marion Aruanno ◽  
Samantha Gozel ◽  
Isabelle Mouyna ◽  
Josie E Parker ◽  
Daniel Bachmann ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Aspergillus Fumigatus ◽  
Molecular Mechanisms ◽  
Drug Transporters ◽  
Major Facilitator Superfamily ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Drug Transporter

Abstract Aspergillus fumigatus is the main cause of invasive aspergillosis, for which azole drugs are the first-line therapy. Emergence of pan-azole resistance among A. fumigatus is concerning and has been mainly attributed to mutations in the target gene (cyp51A). However, azole resistance may also result from other mutations (hmg1, hapE) or other adaptive mechanisms. We performed microevolution experiment exposing an A. fumigatus azole-susceptible strain (Ku80) to sub-minimal inhibitory concentration of voriconazole to analyze emergence of azole resistance. We obtained a strain with pan-azole resistance (Ku80R), which was partially reversible after drug relief, and without mutations in cyp51A, hmg1, and hapE. Transcriptomic analyses revealed overexpression of the transcription factor asg1, several ATP-binding cassette (ABC) and major facilitator superfamily transporters and genes of the ergosterol biosynthesis pathway in Ku80R. Sterol analysis showed a significant decrease of the ergosterol mass under voriconazole exposure in Ku80, but not in Ku80R. However, the proportion of the sterol compounds was similar between both strains. To further assess the role of transporters, we used the ABC transporter inhibitor milbemycine oxime (MLB). MLB inhibited transporter activity in both Ku80 and Ku80R and demonstrated some potentiating effect on azole activity. Criteria for synergism were reached for MLB and posaconazole against Ku80. Finally, deletion of asg1 revealed some role of this transcription factor in controlling drug transporter expression, but had no impact on azole susceptibility. This work provides further insight in mechanisms of azole stress adaptation and suggests that drug transporters inhibition may represent a novel therapeutic target. Lay Summary A pan-azole-resistant strain was generated in vitro, in which drug transporter overexpression was a major trait. Analyses suggested a role of the transporter inhibitor milbemycin oxime in inhibiting drug transporters and potentiating azole activity.

A Functional Role of Intracellular Loops of Human Multidrug Resistance Protein 1

2006 ◽  
Vol 140 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Xiao-Qin Ren ◽  
Tatsuhiko Furukawa ◽  
Masatatsu Yamamoto ◽  
Shunji Aoki ◽  
Motomasa Kobayashi ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Functional Role ◽  
Multidrug Resistance Protein ◽  
Multidrug Resistance Protein 1 ◽  
Resistance Protein ◽  
Intracellular Loops

scholarly journals Functional Role of Arginine 375 in Transmembrane Helix 6 of Multidrug Resistance Protein 4 (MRP4/ABCC4)

2008 ◽  
Vol 74 (4) ◽  
pp. 964-971 ◽  
Author(s):  
Azza A. K. El-Sheikh ◽  
Jeroen J. M. W. van den Heuvel ◽  
Elmar Krieger ◽  
Frans G. M. Russel ◽  
Jan B. Koenderink
Keyword(s):  
Multidrug Resistance ◽  
Functional Role ◽  
Transmembrane Helix ◽  
Multidrug Resistance Protein ◽  
Resistance Protein

scholarly journals Role of ROS/RNS in Preeclampsia: Are Connexins the Missing Piece?

2020 ◽  
Vol 21 (13) ◽  
pp. 4698 ◽  
Author(s):  
María F. Rozas-Villanueva ◽  
Paola Casanello ◽  
Mauricio A. Retamal
Keyword(s):  
Reactive Nitrogen Species ◽  
Molecular Mechanisms ◽  
Cell Communication ◽  
Transmembrane Proteins ◽  
Pregnancy Complication ◽  
Oxygen Species ◽  
Nitrogen Species ◽  
Gap Junction Channels ◽  
Contraction And Relaxation

Preeclampsia is a pregnancy complication that appears after 20 weeks of gestation and is characterized by hypertension and proteinuria, affecting both mother and offspring. The cellular and molecular mechanisms that cause the development of preeclampsia are poorly understood. An important feature of preeclampsia is an increase in oxygen and nitrogen derived free radicals (reactive oxygen species/reactive nitrogen species (ROS/RNS), which seem to be central players setting the development and progression of preeclampsia. Cell-to-cell communication may be disrupted as well. Connexins (Cxs), a family of transmembrane proteins that form hemichannels and gap junction channels (GJCs), are essential in paracrine and autocrine cell communication, allowing the movement of signaling molecules between cells as well as between the cytoplasm and the extracellular media. GJCs and hemichannels are fundamental for communication between endothelial and smooth muscle cells and, therefore, in the control of vascular contraction and relaxation. In systemic vasculature, the activity of GJCs and hemichannels is modulated by ROS and RNS. Cxs participate in the development of the placenta and are expressed in placental vasculature. However, it is unknown whether Cxs are modulated by ROS/RNS in the placenta, or whether this potential modulation contributes to the pathogenesis of preeclampsia. Our review addresses the possible role of Cxs in preeclampsia, and the plausible modulation of Cxs-formed channels by ROS and RNS. We suggest these factors may contribute to the development of preeclampsia.

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