Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In human pigmentary cirrhosis nuclear (pseudo-)inclusions of cytoplasmic material, containing less or more degenerated and therefore faintly stained hemosiderin granules, are to be observed. But sometimes there are also finely fibrillar or granular proteinaceous materials, stainable by the Prussian-blue reaction, lying between the chromatin-strands or occupying the whole nucleus and displacing the chromatin to the nuclear envelope (margination of chromatin). Such uncoloured substances may condense into homogeneous masses and nearly hexagonal (0r related) crystals with a diameter up to 14 micron and a yellow-brownish colour, giving a strongly positive PERL's reaction. In contrast to the preceding stages intranuclear crystals of this kind have been observed in one case only. After destruction of the nuclear envelope and the marginated chromatin the crystals are lying free in the cytoplasm and later on, the cytoplasm being destroyed too, they may be ingested by von Kupffer cells. All the iron containing crystals, to be found in the cytoplasm, derive from former intranuclear inclusions. The intranuclear deposits of iron containing protein are interpreted as ferritin-aggregates. It is supposed that ferritin molecules, built up in the cytoplasm, do enter the nucleus via the pores of the nuclear envelope. Such an event not only signalizes a cytopathologic reaction but in turn may give rise to such additional cytopathologic lesions as cell shrinking and cell death.
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PMID:[Iron containing nuclear inclusions in human pigmentary cirrhosis (author's transl)]. 19 46

Experiments were conducted to examine the topographic arrangement of the polypeptides of the acetylcholine receptor (AcChR) and the nonreceptor Mr 43,000 protein in postsynaptic membranes isolated from Torpedo electric organ. When examined by electron microscopy, greater than 85% of vesicles were not permeable to ferritin or lactoperoxidase (LPO). Exposure to saponin was identified as a suitable procedure to permeabilize the vesicles to macromolecules with minimal alteration of vesicle size or ultrastructure. The sidedness of vesicles was examined morphologically and biochemically. Comparison of the distribution of intramembrane particles on freeze-fractured vesicles and the distribution found in situ indicated that greater than 85% of the vesicles were extracellular-side out. Vesicles labeled with alpha-bungarotoxin (alpha-Bgtx) were reacted with antibodies against alpha-BgTx or against purified AcChR of Torpedo. Bound antibodies were detected by the use of ferritin-conjugated goat anti-rabbit antibody and were located on the outside of greater than 99% of labeled vesicles. Similar results were obtained for normal vesicles or vesicles exposed to saponin. Quantification of the amount of [3H]-alpha-BgTx bound to vesicles before and after they were made permeable with saponin indicated that less than 5% of alpha-BgTx binding sites were cryptic in normal vesicles. It was concluded that greater than 95% of postsynaptic membranes were oriented extracellular-side out. LPO-catalyzed radioiodinations were performed on normal and saponin-treated vesicles and on vesicles from which the Mr (relative molecular mass) 43,000 protein had been removed by alkaline extraction. In normal vesicles, polypeptides of the AcChR were iodinated while the Mr 43,000 protein was not. In vesicles made permeable with saponin, the pattern of labeling of AcChR polypeptides was unchanged, but the Mr 43,000 protein was heavily iodinated. The relative iodination of AcChR polypeptides was unchanged in membranes equilibrated with agonist or with alpha-BgTx or after alkaline-extraction. It was concluded that the Mr 43,000 protein is present on the intracellular surface of the postsynaptic membrane and that AcChR polypeptides are exposed on the extracellular surface.
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PMID:Nicotinic postsynaptic membranes from Torpedo: sidedness, permeability to macromolecules, and topography of major polypeptides. 617 28

The occurrence of endocytotic mechanisms in human small-intestinal absorptive cells was investigated by culturing biopsy specimens in the presence of horseradish peroxidase (HRP), lactoperoxidase (LPO), and ferritin. The results indicate that both HRP and LPO entered the cells by apical endocytosis, after which they were transported via apical vesicles and tubules to the lysosome-like bodies. Ferritin, which showed a distinct affinity for the cell-coat glycoproteins, was not interiorized by the absorptive cells. These findings suggest that although human absorptive cells have an endocytotic mechanism, possibly fluid-phase endocytosis, cell-coat glycoproteins are not taken up by the cells, as indicated by the absence of ferritin in the apical vesicles and tubules, as well as the lysosome-like bodies. These findings provide indirect support for our hypothesis that the lysosome-like bodies have a function in the regulation of cell-coat glycoprotein transport via a crinophagic mechanism (fusion of apical vesicles and tubules with lysosome-like bodies) rather than via an exocytotic-endocytotic mechanism.
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PMID:Endocytosis in absorptive cells of cultured human small-intestinal tissue: horseradish peroxidase, lactoperoxidase, and ferritin as markers. 722 1