Involvement of Glycolipid-Enriched Domains in the Transduction Mechanism of Neurotrophins in Cultured Neurons

1999 ◽  
Vol 19 (5) ◽  
pp. 385-395 ◽  
Author(s):  
P. Palestini ◽  
M. Masserini ◽  
G. Bottiroli ◽  
J. Brunner ◽  
T. Mutoh ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Large Body ◽  
Protein Composition ◽  
Membrane Structures ◽  
Associated Proteins ◽  
Dynamic Structures ◽  
Related Proteins

Specialized domains, displaying a peculiar lipid and protein composition, are present within the plasma membrane of mammalian cells and play a pivotal role in fundamental membrane-associated events. Among lipids, sphingolipids (in particular glycolipids and sphingomyelin) are characteristically enriched within such domains. Moreover, a series of functionally related proteins is present, suggesting the involvement of these membrane structures in the mechanism of signal transduction and lipid/protein sorting. An increasing body of evidence suggests that domains are dynamic structures, and that their dynamic fluctuations can modulate the activity of domain-associated proteins through changes of glycolipid–protein interaction. Even if a large body of experimental investigation has been carried out on eukaryotic cells, only little attention has been paid to the neuron. The purpose of the present review is to summarize the observations implying a functional role of glycolipid-enriched domains in cultured rat cerebellar granule cells.

scholarly journals Scanning Electron-Assisted Dielectric Microscopy Reveals Autophagosome Formation by LC3 and ATG12 in Cultured Mammalian Cells

2021 ◽  
Vol 22 (4) ◽  
pp. 1834
Author(s):  
Tomoko Okada ◽  
Toshihiko Ogura
Keyword(s):  
Mammalian Cells ◽  
Culture Medium ◽  
Related Gene ◽  
Autophagosome Formation ◽  
Intact Cells ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
The Difference ◽  
Related Proteins ◽  
Scanning Electron

Autophagy is an intracellular self-devouring system that plays a central role in cellular recycling. The formation of functional autophagosomes depends on several autophagy-related proteins, including the microtubule-associated proteins 1A/1B light chain 3 (LC3) and the conserved autophagy-related gene 12 (Atg12). We have recently developed a novel scanning electron-assisted dielectric microscope (SE-ADM) for nanoscale observations of intact cells. Here, we used the SE-ADM system to observe LC3- and Atg12-containing autophagosomes in cells labelled in the culture medium with antibodies conjugated to colloidal gold particles. We observed that, during autophagosome formation, Atg12 localized along the actin meshwork structure, whereas LC3 formed arcuate or circular alignments. Our system also showed a difference in the distribution of LC3 and Atg12; Atg12 was broadly distributed while LC3 was more localized. The difference in the spatial distribution demonstrated by our system explains the difference in the size of fluorescent spots due to the fluorescently labelled antibodies observed using optical microscopy. The direct SE-ADM observation of cells should thus be effective in analyses of autophagosome formation.

Role of Pax6 in development of the cerebellar system

Development ◽  
1999 ◽  
Vol 126 (16) ◽  
pp. 3585-3596 ◽  
Author(s):  
D. Engelkamp ◽  
P. Rashbass ◽  
A. Seawright ◽  
V. van Heyningen
Keyword(s):  
Cell Proliferation ◽  
Cell Migration ◽  
Granule Cell ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Long Distance ◽  
Cerebellar Granule ◽  
Precerebellar Nuclei ◽  
Rhombic Lip

Post-mitotic neurons generated at the rhombic lip undertake long distance migration to widely dispersed destinations, giving rise to cerebellar granule cells and the precerebellar nuclei. Here we show that Pax6, a key regulator in CNS and eye development, is strongly expressed in rhombic lip and in cells migrating away from it. Development of some structures derived from these cells is severely affected in Pax6-null Small eye (Pax6(Sey)/Pax6(Sey)) embryos. Cell proliferation and initial differentiation seem unaffected, but cell migration and neurite extension are disrupted in mutant embryos. Three of the five precerebellar nuclei fail to form correctly. In the cerebellum the pre-migratory granule cell sub-layer and fissures are absent. Some granule cells are found in ectopic positions in the inferior colliculus which may result from the complete absence of Unc5h3 expression in Pax6(Sey)/Pax6(Sey) granule cells. Our results suggest that Pax6 plays a strong role during hindbrain migration processes and at least part of its activity is mediated through regulation of the netrin receptor Unc5h3.

Novel role of the Ca2+-ATPase in NMDA-induced intracellular acidification

1999 ◽  
Vol 277 (4) ◽  
pp. C717-C727 ◽  
Author(s):  
Mei-Lin Wu ◽  
Jeng-Haur Chen ◽  
Wei-Hao Chen ◽  
Yu-Jen Chen ◽  
Kuan-Chou Chu
Keyword(s):  
Binding Sites ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Feedback Signal ◽  
Free Medium ◽  
Intracellular Acidosis ◽  
Eosin B ◽  
Intracellular Ca ◽  
New Evidence

The mechanism involved in N-methyl-d-glucamine (NMDA)-induced Ca2+-dependent intracellular acidosis is not clear. In this study, we investigated in detail several possible mechanisms using cultured rat cerebellar granule cells and microfluorometry [fura 2-AM or 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein-AM]. When 100 μM NMDA or 40 mM KCl was added, a marked increase in the intracellular Ca2+ concentration ([Ca2+]i) and a decrease in the intracellular pH were seen. Acidosis was completely prevented by the use of Ca2+-free medium or 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-AM, suggesting that it resulted from an influx of extracellular Ca2+. The following four mechanisms that could conceivably have been involved were excluded: 1) Ca2+ displacement of intracellular H+ from common binding sites; 2) activation of an acid loader or inhibition of acid extruders; 3) overproduction of CO2 or lactate; and 4) collapse of the mitochondrial membrane potential due to Ca2+uptake, resulting in inhibition of cytosolic H+ uptake. However, NMDA/KCl-induced acidosis was largely prevented by glycolytic inhibitors (iodoacetate or deoxyglucose in glucose-free medium) or by inhibitors of the Ca2+-ATPase (i.e., Ca2+/H+exchanger), including La3+, orthovanadate, eosin B, or an extracellular pH of 8.5. Our results therefore suggest that Ca2+-ATPase is involved in NMDA-induced intracellular acidosis in granule cells. We also provide new evidence that NMDA-evoked intracellular acidosis probably serves as a negative feedback signal, probably with the acidification itself inhibiting the NMDA-induced [Ca2+]iincrease.

scholarly journals Role of Calcineurin Signaling in Membrane Potential-Regulated Maturation of Cerebellar Granule Cells

2009 ◽  
Vol 29 (9) ◽  
pp. 2938-2947 ◽  
Author(s):  
M. Okazawa ◽  
H. Abe ◽  
M. Katsukawa ◽  
K. Iijima ◽  
T. Kiwada ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Cerebellar Granule ◽  
Calcineurin Signaling

scholarly journals Function of Protein S-Palmitoylation in Immunity and Immune-Related Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuqi Zhang ◽  
Ziran Qin ◽  
Wenhuan Sun ◽  
Feng Chu ◽  
Fangfang Zhou
Keyword(s):  
Protein Interactions ◽  
Protein Function ◽  
Mammalian Cells ◽  
Large Body ◽  
Protein S ◽  
Cellular Membrane ◽  
Immune Signaling ◽  
Substrate Protein ◽  
Associated Proteins ◽  
Immunologic Diseases

Protein S-palmitoylation is a covalent and reversible lipid modification that specifically targets cysteine residues within many eukaryotic proteins. In mammalian cells, the ubiquitous palmitoyltransferases (PATs) and serine hydrolases, including acyl protein thioesterases (APTs), catalyze the addition and removal of palmitate, respectively. The attachment of palmitoyl groups alters the membrane affinity of the substrate protein changing its subcellular localization, stability, and protein-protein interactions. Forty years of research has led to the understanding of the role of protein palmitoylation in significantly regulating protein function in a variety of biological processes. Recent global profiling of immune cells has identified a large body of S-palmitoylated immunity-associated proteins. Localization of many immune molecules to the cellular membrane is required for the proper activation of innate and adaptive immune signaling. Emerging evidence has unveiled the crucial roles that palmitoylation plays to immune function, especially in partitioning immune signaling proteins to the membrane as well as to lipid rafts. More importantly, aberrant PAT activity and fluctuations in palmitoylation levels are strongly correlated with human immunologic diseases, such as sensory incompetence or over-response to pathogens. Therefore, targeting palmitoylation is a novel therapeutic approach for treating human immunologic diseases. In this review, we discuss the role that palmitoylation plays in both immunity and immunologic diseases as well as the significant potential of targeting palmitoylation in disease treatment.

Targeting DNA Repair Systems in Antitubercular Drug Development

2019 ◽  
Vol 26 (8) ◽  
pp. 1494-1505 ◽  
Author(s):  
Alina Minias ◽  
Anna Brzostek ◽  
Jarosław Dziadek
Keyword(s):  
Dna Repair ◽  
Protein Crystal ◽  
Model Organisms ◽  
Dna Repair Genes ◽  
Associated Proteins ◽  
Related Proteins ◽  
Repair Genes

Infections with Mycobacterium tuberculosis, the causative agent of tuberculosis, are difficult to treat using currently available chemotherapeutics. Clinicians agree on the urgent need for novel drugs to treat tuberculosis. In this mini review, we summarize data that prompts the consideration of DNA repair-associated proteins as targets for the development of new antitubercular compounds. We discuss data, including gene expression data, that highlight the importance of DNA repair genes during the pathogenic cycle as well as after exposure to antimicrobials currently in use. Specifically, we report experiments on determining the essentiality of DNA repair-related genes. We report the availability of protein crystal structures and summarize discovered protein inhibitors. Further, we describe phenotypes of available gene mutants of M. tuberculosis and model organisms Mycobacterium bovis and Mycobacterium smegmatis. We summarize experiments regarding the role of DNA repair-related proteins in pathogenesis and virulence performed both in vitro and in vivo during the infection of macrophages and animals. We detail the role of DNA repair genes in acquiring mutations, which influence the rate of drug resistance acquisition.

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