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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied with morphometric methods the endocytosis by pheochromocytoma cells of a conjugate of wheat germ agglutinin with ferritin (WGA-Ft) and of horseradish peroxidase (HRP). Quantitative studies indicated that WGA-Ft was cleared slowly from cell surfaces and that it was not recycled to the surface. Cells labeled with WGA-Ft for 15 min at room temperature were washed and incubated in medium containing HRP for 15 or 30 min at 37 degrees C. The greatest proportion of labeled vesicles and tubules contained only WGA-Ft (83.4% at 15 min and 85.3% at 30 min). A very small fraction of labeled vesicles and tubules contained only HRP (0.2% at 15 min and 0.9% at 30 min). Vesicles and tubules at the Golgi apparatus were labeled almost exclusively with WGA-Ft (97% at 15 min and 30 min); the rest had both labels. Most labeled lysosomes contained both labels (80.1% at 15 min and 80.8% at 30 min). Of the remainder more contained WGA-Ft alone (20% at 15 min and 10.9% at 30 min), then HRP alone (none at 15 min and 8.2% at 30 min). In contrast to the various and varying patterns of labeling with WGA-Ft and HRP of the other organelles studied, the vast majority of endosomes contained both markers (94.1% at 15 min and 100% at 30 min); the rest contained WGA-Ft only. These results demonstrate that endosomes are recipients of both fluid phase and adsorptive endocytosis markers; these findings are consistent with the hypothesis that endosomes mediate the sorting out and subsequent intracellular traffic of membrane bound and fluid phase markers. Cisterns of the Golgi apparatus did not contain WGA-Ft; in sharp contrast, when WGA-HRP was used, the cisterns of the Golgi apparatus consistently contained HRP.
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PMID:Endosomes and Golgi vesicles in adsorptive and fluid phase endocytosis. 654 23

An iron-rich protein was isolated from the Archaeon Halobacterium salinarum sharing a sequence identity of 35% with the starvation-induced DNA-binding protein, DpsA, of Synechecoccus sp. PCC 7942. It consists of 20 kDa subunits, forming a dodecameric structure. The protein exhibits a ferric iron loading of up to 103 Fe ions/mol of holoprotein. CD spectra are consistent with an alpha-helical contribution of 58%. The UV/visible spectrum provides no evidence for the presence of haem groups. This protein exhibits features of a non-haem-type bacterial ferritin although it shares only little sequence homology with non-haem bacterial ferritin.
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PMID:Characterization of a non-haem ferritin of the Archaeon Halobacterium salinarum, homologous to Dps (starvation-induced DNA-binding protein). 1219 73

Clinical application of platinum-based anticancer drugs is largely limited by severe general toxicity and drug resistance. Drug delivery systems with tumor-targeting potential are highly desired for improving the efficacy and applicability of these drugs. This study describes an alternative strategy for the delivery of platinum drugs (cisplatin, carboplatin and oxaliplatin) by encapsulating each of them in the cavity of apoferritin (AFt). The encapsulation was achieved through manipulating the pH-dependent unfolding-refolding process of AFt at pH 2.0 and 7.4, respectively, in saturated drug solution. UV-vis spectrometry, circular dichroism spectrometry, dynamic light scattering, and inductively coupled plasma mass spectrometry were used to characterize the AFt-drug complexes. The loading capacity of AFt varies with respective drugs and the structural integrity of the protein shell remains intact after encapsulation. In vitro assays on the rat pheochromocytoma cell line (PC12) show that AFt-cisplatin inhibits the cells in a slow but sustaining mode and the cellular uptake of platinum is enhanced by AFt. AFt-carboplatin and AFt-oxaliplatin complexes only exhibit a marginal cytotoxicity towards this cell line under similar concentrations.
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PMID:Characterization and cellular uptake of platinum anticancer drugs encapsulated in apoferritin. 1950 11

In this article, we demonstrate the connection between intracellular iron storage and oxidative stress response in cyanobacteria. Iron is essential for the survival of all organisms. However, the redox properties that make iron a valuable cofactor also lead to oxidative interactions, resulting in the formation of harmful radicals. Therefore, iron accumulation in cells should be tightly regulated, a process in which ferritin family proteins play an important role. Synechocystis sp. PCC 6803 contains two ferritin-type storage complexes, bacterioferritin and MrgA. Previous studies demonstrated the role of bacterioferritin and MrgA in iron storage. In addition, MrgA was found to play a key role in oxidative stress response. Here, we examined the dual role of the ferritin family proteins using physiological and transcriptomic approaches. Microarray analysis of iron-limited wild-type and DeltamrgA cultures revealed a substantial up-regulation of oxidative stress-related genes in mutant cells. The PerR regulator was found to play an important role in that process. Furthermore, we were able to demonstrate the connection between internal iron quota, the presence of the two storage complexes, and the sensitivity to externally applied oxidative stress. These data suggest a pivotal role for the ferritin-type proteins of Synechocystis sp. PCC 6803 in coordinating iron homeostasis and in oxidative stress response. The combined action of the two complexes allows for the safe accumulation and release of iron from storage by minimizing damage resulting from interactions between reduced iron and the oxygen radicals that are produced in abundance by the photosynthetic apparatus.
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PMID:The mechanism of iron homeostasis in the unicellular cyanobacterium synechocystis sp. PCC 6803 and its relationship to oxidative stress. 1956 Nov 20

Knowledge on the regulatory mechanisms controlling iron homeostasis in cyanobacteria is limited. In Anabaena sp. PCC 7120, the ferric uptake regulator FurA is a constitutive and essential protein whose expression is induced under iron deprivation. Our previous analyses have shown that this protein acts as a global transcriptional regulator, controlling the expression of several genes belonging to different functional categories, including schT, a gene coding for a TonB-dependent schizokinen transporter. In the present study we analysed the impact of FurA overexpression and iron availability on the transcriptional modulation of a broad range of Anabaena iron uptake, transport, storage and cellular iron utilization mechanisms, including enzymes involved in siderophore biosynthesis, TonB-dependent siderophore outer membrane transporters, siderophore periplasmic binding proteins, ABC inner membrane permeases, ferritin Dps family proteins, and enzymes involved in tetrapyrrole biosynthesis. By combining reverse transcription-PCR analyses, electrophoretic mobility shift assays and DNase I footprinting experiments, we defined a variety of novel direct iron-dependent transcriptional targets of this metalloregulator, including genes encoding at least five enzymes involved in the tetrapyrrole biosynthesis pathway. The results unravel the role of FurA as the master regulator of iron homeostasis in Anabaena sp. PCC 7120, providing new insights into the Fur regulons in cyanobacteria.
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PMID:FurA is the master regulator of iron homeostasis and modulates the expression of tetrapyrrole biosynthesis genes in Anabaena sp. PCC 7120. 2306 98

Pheochromocytomas are catecholamine-secreting tumors. These tumors are rare in children, and they may be associated with hereditary syndromes such as von Hippel-Lindau (VHL) disease. Most pediatric patients with pheochromocytoma present with sustained hypertension, while 10% to 69% of adult patients are asymptomatic. Herein, we present the case of a 12-yr-old Japanese girl with pheochromocytoma due to a germline mutation in the VHL (Arg161Gln). The only complaint was loss of weight. Pyrexia, anemia, and increases in C-reactive protein (CRP) and ferritin were observed. Abdominal ultrasonography revealed a right adrenal gland tumor. Fractionated catecholamines and metanephrines in plasma and 24-h collected urine revealed elevated levels of norepinephrine and normetanephrine. Although hypertension and tachycardia were inapparent by an ordinary physical examination, paroxysmal mild hypertension and tachycardia were identified by a thorough examination after walking and abdominal compression. Paroxysmal hypertension and tachycardia were profound during operation. In conclusion, pheochromocytoma can be a consideration in the differential diagnosis of weight loss. Hypertension and tachycardia can be inapparent and paroxysmal in pediatric patients as well as in adults; thus, thorough assessment should be repeated.
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PMID:A pediatric case of pheochromocytoma without apparent hypertension associated with von Hippel-Lindau disease. 2966 68