Effects of Deuterium Oxide on Growth, Proton Extrusion, Potassium Influx, and in Vitro Plasma Membrane Activities in Maize Root Segments

Maize root tips were incubated in vivo with radioactive glucose, choline or diazotized sulphanilic acid. Membrane fractions were prepared from radioactive and non-radioactive roots. The transfer of radioactivity between mixed membrane fractions has enabled a quantitative system to be developed to study in vitro membrane fusion between Golgi apparatus and plasma membrane-rich fractions. Membrane fusion was found to be dependent on time, temperature, Mn2+ and Ca2+. Mn2+ was as effective as Ca2+, other divalent cations had a moderate or no effect. The effect of various substances, including inhibitors of microtubular and microfilament assembly and blocking reagents for sulphydryl group on membrane fusion has been investigated. The process appears to be dependent on the membrane proteins or glycoproteins; trypsinization of mixed membranes prior to the addition of Ca2+ inhibited significantly the fusion process. SDS-polyacrylamide gel electrophoresis of trypsin-treated membranes revealed the selective loss of one particular polypeptide which could play a role in membrane fusion.

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Effects of Cr on proton extrusion, potassium uptake and transmembrane electric potential in maize root segments.

Plant Cell & Environment ◽

10.1111/1365-3040.ep11611843 ◽

1985 ◽

Vol 8 (9) ◽

pp. 721-726

Author(s):

P. Zaccheo ◽

M. Cocucci ◽

S. Cocucci

Keyword(s):

Electric Potential ◽

Potassium Uptake ◽

Maize Root ◽

Proton Extrusion ◽

Root Segments

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Faculty Opinions recommendation of In vitro fusion between Saccharomyces cerevisiae secretory vesicles and cytoplasmic-side-out plasma membrane vesicles.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1010821.167908 ◽

2002 ◽

Author(s):

Miguel Penalva

Keyword(s):

Saccharomyces Cerevisiae ◽

Plasma Membrane ◽

Membrane Vesicles ◽

Secretory Vesicles ◽

Plasma Membrane Vesicles ◽

Cytoplasmic Side

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RNF141 interacts with KRAS to promote colorectal cancer progression

Oncogene ◽

10.1038/s41388-021-01877-4 ◽

2021 ◽

Author(s):

Jiuna Zhang ◽

Xiaoyu Jiang ◽

Jie Yin ◽

Shiying Dou ◽

Xiaoli Xie ◽

...

Keyword(s):

Colorectal Cancer ◽

Plasma Membrane ◽

Tumor Growth ◽

Cancer Progression ◽

Critical Role ◽

Ring Finger ◽

Immunohistochemical Analysis ◽

Bimolecular Fluorescence Complementation

AbstractRING finger proteins (RNFs) play a critical role in cancer initiation and progression. RNF141 is a member of RNFs family; however, its clinical significance, roles, and mechanism in colorectal cancer (CRC) remain poorly understood. Here, we examined the expression of RNF141 in 64 pairs of CRC and adjacent normal tissues by real-time PCR, Western blot, and immunohistochemical analysis. We found that there was more expression of RNF141 in CRC tissue compared with its adjacent normal tissue and high RNF141 expression associated with T stage. In vivo and in vitro functional experiments were conducted and revealed the oncogenic role of RNF141 in CRC. RNF141 knockdown suppressed proliferation, arrested the cell cycle in the G1 phase, inhibited migration, invasion and HUVEC tube formation but promoted apoptosis, whereas RNF141 overexpression exerted the opposite effects in CRC cells. The subcutaneous xenograft models showed that RNF141 knockdown reduced tumor growth, but its overexpression promoted tumor growth. Mechanistically, liquid chromatography-tandem mass spectrometry indicated RNF141 interacted with KRAS, which was confirmed by Co-immunoprecipitation, Immunofluorescence assay. Further analysis with bimolecular fluorescence complementation (BiFC) and Glutathione-S-transferase (GST) pull-down assays showed that RNF141 could directly bind to KRAS. Importantly, the upregulation of RNF141 increased GTP-bound KRAS, but its knockdown resulted in a reduction accordingly. Next, we demonstrated that RNF141 induced KRAS activation via increasing its enrichment on the plasma membrane not altering total KRAS expression, which was facilitated by the interaction with LYPLA1. Moreover, KRAS silencing partially abolished the effect of RNF141 on cell proliferation and apoptosis. In addition, our findings presented that RNF141 functioned as an oncogene by upregulating KRAS activity in a manner of promoting KRAS enrichment on the plasma membrane in CRC.

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Norepinephrine Protects against Methamphetamine Toxicity through β2-Adrenergic Receptors Promoting LC3 Compartmentalization

International Journal of Molecular Sciences ◽

10.3390/ijms22137232 ◽

2021 ◽

Vol 22 (13) ◽

pp. 7232

Author(s):

Gloria Lazzeri ◽

Carla L. Busceti ◽

Francesca Biagioni ◽

Cinzia Fabrizi ◽

Gabriele Morucci ◽

...

Keyword(s):

Plasma Membrane ◽

Light Chain ◽

Adrenergic Receptors ◽

Cell Damage ◽

Protective Effects ◽

Autophagy Flux ◽

Brain Areas ◽

Indirect Consequence

Norepinephrine (NE) neurons and extracellular NE exert some protective effects against a variety of insults, including methamphetamine (Meth)-induced cell damage. The intimate mechanism of protection remains difficult to be analyzed in vivo. In fact, this may occur directly on target neurons or as the indirect consequence of NE-induced alterations in the activity of trans-synaptic loops. Therefore, to elude neuronal networks, which may contribute to these effects in vivo, the present study investigates whether NE still protects when directly applied to Meth-treated PC12 cells. Meth was selected based on its detrimental effects along various specific brain areas. The study shows that NE directly protects in vitro against Meth-induced cell damage. The present study indicates that such an effect fully depends on the activation of plasma membrane β2-adrenergic receptors (ARs). Evidence indicates that β2-ARs activation restores autophagy, which is impaired by Meth administration. This occurs via restoration of the autophagy flux and, as assessed by ultrastructural morphometry, by preventing the dissipation of microtubule-associated protein 1 light chain 3 (LC3) from autophagy vacuoles to the cytosol, which is produced instead during Meth toxicity. These findings may have an impact in a variety of degenerative conditions characterized by NE deficiency along with autophagy impairment.

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Familial Parkinson's Disease Mutant E46K α-Synuclein Localizes to Membranous Structures, Forms Aggregates, and Induces Toxicity in Yeast Models

ISRN Neurology ◽

10.5402/2011/521847 ◽

2011 ◽

Vol 2011 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Michael Fiske ◽

Michael White ◽

Stephanie Valtierra ◽

Sara Herrera ◽

Keith Solvang ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Plasma Membrane ◽

Mutant Form ◽

Phospholipid Membrane ◽

Endomembrane System ◽

Wild Type ◽

Significant Toxicity ◽

Familial Parkinson’S Disease

In Parkinson’s disease (PD), midbrain dopaminergic neuronal death is linked to the accumulation of aggregated α-synuclein. The familial PD mutant form of α-synuclein, E46K, has not been thoroughly evaluated yet in an organismal model system. Here, we report that E46K resembled wild-type (WT) α-synuclein in Saccharomyces cerevisiae in that it predominantly localized to the plasma membrane, and it did not induce significant toxicity or accumulation. In contrast, in Schizosaccharomyces pombe, E46K did not associate with the plasma membrane. Instead, in one strain, it extensively aggregated in the cytoplasm and was as toxic as WT. Remarkably, in another strain, E46K extensively associated with the endomembrane system and was more toxic than WT. Our studies recapitulate and extend aggregation and phospholipid membrane association properties of E46K previously observed in vitro and cell culture. Furthermore, it supports the notion that E46K generates toxicity partly due to increased association with endomembrane systems within cells.

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