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

Synchronization of the secretory cycle in vivo was obtained by injecting isoprenaline as an inducer of secretion. A quantitative correlation between enzyme release, its subsequent reaccumulation, and the sequence of ultrastructural changes was found. At the ultrastructural level secretion was paralleled by depletion of zymogen granules through fusion of the granule membrane with the lumen membrane and discharge of the content. Each zymogen granule membrane, once connected with the lumen, acted as a lumen membrane. Fusion was thus sequential and resulted in a dramatic enlargement of the lumen space. During the entire process the passage between the lumen and the intercellular space remained blocked by the tight junctions, as shown by their impenetrability to ferritin. Reduction of the lumen size following enzyme discharge seemed to be achieved by withdrawal of lumen membrane in the form of small smooth vesicles which appeared mostly in the apical part of the cell. At the same time, the cell retracted towards the lumen, the whole process being completed within 2 hr from onset of secretion. Disappearance of the smooth vesicle followed, concomitant with formation of many condensing vacuoles and appearance of mature zymogen granules. The fate of the zymogen granule membrane, including its fusion with the lumen membrane, resorption in the form of small smooth vesicles, and its eventual reutilization mediated by the Golgi system, is discussed.
 ...
PMID:Dynamic changes in the ultrastructure of the acinar cell of the rat parotid gland during the secretory cycle. 576 73

The cellular sites of the glycoproteins Group 1 allergen (glycoprotein 1) and Antigen A (glycoprotein 2) in mature ryegrass pollen have been investigated by immunoelectron microscopy. Radioimmunoassays confirm previous findings of cross-reactivity between the purified glycoprotein antigens at the high immunoglobulin G (IgG) concentrations used for localization. Freeze-drying of anthers followed by anhydrous processing has been employed because of the water solubility and mobility of the glycoproteins. A double-embedding technique has been developed. This involves, first, embedding anthers in the water-soluble plastic resin JB-4, sectioning and incubating in ferritin-labelled antisera by the indirect method. The sections are then embedded in Spurr's resin for ultra-thin sectioning. Both glycoproteins are found in the following sites: (1) exine and intine wall layers; (2) pollen cytoplasm; (3) the orbicules and anther loculus; and (4) the anther cuticle. In the exine arcades and surface and in the anther loculus, the ferritin label is bound to pollenkitt. The finding that the glycoproteins are in similar sites is predictable in view of the cross-specificity of the antisera. The extent of antibody penetration of the plastic sections has been examined; labelling is confined to cut grains and absent from intact grains.
 ...
PMID:Immunocytochemical localization of water-soluble glycoproteins, including group 1 allergen, in pollen of ryegrass, Lolium perenne, using ferritin-labelled antibody. 717 55