scholarly journals Localization of protein disulfide isomerase on plasma membranes of rat exocrine pancreatic cells.

1988 ◽  
Vol 36 (8) ◽  
pp. 1069-1074 ◽  
Author(s):  
S Akagi ◽  
A Yamamoto ◽  
T Yoshimori ◽  
R Masaki ◽  
R Ogawa ◽  
...  
Keyword(s):  
Protein Disulfide Isomerase ◽  
Plasma Membranes ◽  
Secretory Granules ◽  
Amorphous Material ◽  
Protein A ◽  
Disulfide Isomerase ◽  
Gold Particles ◽  
Pancreatic Cells ◽  
Acinar Lumen ◽  
Protein Disulfide

We investigated immunocytochemically the ultrastructural localization of protein disulfide isomerase (PDI) in rat pancreatic exocrine cells by use of the post-embedding protein A-gold technique. We found that not only the endoplasmic reticulum (ER) and nuclear envelope but also the trans-Golgi cisternae, secretory granules, and plasma membranes were heavily labeled with gold particles. Labeling density of the gold particles in the rough ER and plasma membranes of the exocrine pancreatic cells was twofold and twentyfold greater, respectively, than that of hepatocytes. In the acinar lumen, amorphous material presumably corresponding to the secreted zymogens was also labeled with gold particles. These results suggest that in rat exocrine pancreatic cells a significant amount of PDI is transported to the plasma membrane and secreted to the acinar lumen.

scholarly journals Distribution of protein disulfide isomerase in rat hepatocytes.

1988 ◽  
Vol 36 (12) ◽  
pp. 1533-1542 ◽  
Author(s):  
S Akagi ◽  
A Yamamoto ◽  
T Yoshimori ◽  
R Masaki ◽  
R Ogawa ◽  
...  
Keyword(s):  
Protein Disulfide Isomerase ◽  
Plasma Membranes ◽  
Smooth Endoplasmic Reticulum ◽  
Control Level ◽  
Rat Hepatocytes ◽  
Order Structure ◽  
Disulfide Isomerase ◽  
Gold Particles ◽  
Protein Disulfide

We investigated quantitatively the distribution of protein disulfide isomerase (PDI) in rat hepatocytes by immunocytochemistry using a post-embedding protein A-gold technique. In hepatocytes, gold particles were mainly localized in the intracisternal space of the rough and smooth endoplasmic reticulum (ER) and nuclear envelopes. Autolysosomes engulfing ER were occasionally densely labeled, especially in rat hepatocytes previously treated with leupeptin in vivo, suggesting that the autophagosome-autolysosome system may be an important route for degradation of PDI. A few gold particles were also found on the plasma membranes. Localization of gold particles on the other subcellular organelles, such as Golgi apparatus, peroxisomes, and nuclear matrix, was sparse and at the control level. The predominant localization of PDI on the intracisternal surface of the ER and nuclear envelope supports a potential role of PDI in the formation of disulfide bonds of nascent polypeptides, thus accelerating formation of the higher-order structure of secretory and membrane proteins and rendering the translocation process irreversible.

scholarly journals Distribution of protein disulfide isomerase in rat epiphyseal chondrocytes.

1989 ◽  
Vol 37 (12) ◽  
pp. 1835-1844 ◽  
Author(s):  
S Akagi ◽  
A Yamamoto ◽  
T Yoshimori ◽  
R Masaki ◽  
R Ogawa ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Disulfide Bonds ◽  
Protein Disulfide Isomerase ◽  
Protein A ◽  
Secretory Proteins ◽  
Disulfide Isomerase ◽  
Gold Particles ◽  
Golgi Compartment ◽  
Preferential Binding ◽  
Protein Disulfide

We investigated the intracellular distribution of protein disulfide isomerase (PDI) in rat epiphyseal chondrocytes by immunocytochemistry, using a post-embedding protein A-gold technique. Gold particles were localized primarily in the cisternal space of the rough endoplasmic reticulum (ER) and nuclear envelopes. The ER cisternae of the chondrocytes in all the differentiating epiphyseal zones--resting, proliferative, pre-hypertrophic, and hypertrophic--were equally and highly labeled. The labeling density of the cisternal space of the dilated ER, probably reflecting marked accumulation of secretory proteins such as procollagen, was always higher than that of the non-dilated ER. In the dilated cisternal space, gold particles were freely and evenly distributed, without preferential binding to the luminal surface of the ER membranes. We suggest that PDI catalyzes the formation of disulfide bonds of various secretory proteins, perhaps type II procollagen, in the cisternal space of the ER in epiphyseal chondrocytes. The exclusive localization of gold particles in the cisternal space of the ER and nuclear envelopes and the lack of gold particles in the Golgi apparatus, including cis-Golgi cisternae, indicate that PDI is an ER-soluble protein in the chondrocytes and is presumably sorted out in some pre-Golgi compartment and not transported to the Golgi apparatus.

scholarly journals Human Eosinophil Leukocytes Express Protein Disulfide Isomerase in Secretory Granules and Vesicles

2014 ◽  
Vol 62 (6) ◽  
pp. 450-459 ◽  
Author(s):  
Felipe F. Dias ◽  
Kátia B. Amaral ◽  
Lívia A. S. Carmo ◽  
Revital Shamri ◽  
Ann M. Dvorak ◽  
...  
Keyword(s):  
Protein Disulfide Isomerase ◽  
Secretory Granules ◽  
Human Eosinophil ◽  
Disulfide Isomerase ◽  
Protein Disulfide

scholarly journals The transmembrane protein disulfide isomerase TMX1 negatively regulates platelet responses

Blood ◽  
2019 ◽  
Vol 133 (3) ◽  
pp. 246-251 ◽  
Author(s):  
Zhenzhen Zhao ◽  
Yi Wu ◽  
Junsong Zhou ◽  
Fengwu Chen ◽  
Aizhen Yang ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Protein Disulfide Isomerase ◽  
Transmembrane Protein ◽  
Protein A ◽  
Atp Release ◽  
Platelet Surface ◽  
Knockout Mouse Model ◽  
Disulfide Isomerase ◽  
Protein Disulfide

Abstract Secreted platelet protein disulfide isomerases, PDI, ERp57, ERp5, and ERp72, have important roles as positive regulators of platelet function and thrombosis. Thioredoxin-related transmembrane protein 1 (TMX1) was the first described transmembrane member of the protein disulfide isomerase family of enzymes. Using a specific antibody, the recombinant extracellular domain of TMX1 (rTMX1) protein, a knockout mouse model, and a thiol-labeling approach, we examined the role of TMX1 in platelet function and thrombosis. Expression of TMX1 on the platelet surface increased with thrombin stimulation. The anti-TMX1 antibody increased platelet aggregation induced by convulxin and thrombin, as well as potentiated platelet ATP release. In contrast, rTMX1 inhibited platelet aggregation and ATP release. TMX1-deficient platelets had increased aggregation, ATP release, αIIbβ3 activation, and P-selectin expression, which were reversed by addition of rTMX1. TMX1-knockout mice had increased incorporation of platelets into a growing thrombus in an FeCl3-induced mesenteric arterial injury model, as well as shortened tail-bleeding times. rTMX1 oxidized thiols in the αIIbβ3 integrin and TMX1-deficient platelets had increased thiols in the β3 subunit of αIIbβ3, consistent with oxidase activity of rTMX1 against αIIbβ3. Thus, TMX1 is the first identified extracellular inhibitor of platelet function and the first disulfide isomerase that negatively regulates platelet function.

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