scholarly journals Protein disulfide isomerase isomerizes non-native disulfide bonds in human proinsulin independent of its peptide-binding activity

2011 ◽  
Vol 20 (3) ◽  
pp. 588-596 ◽  
Author(s):  
Jeannette Winter ◽  
Stefan Gleiter ◽  
Peter Klappa ◽  
Hauke Lilie
Keyword(s):  
Disulfide Bonds ◽  
Protein Disulfide Isomerase ◽  
Peptide Binding ◽  
Binding Activity ◽  
Disulfide Isomerase ◽  
Human Proinsulin ◽  
Protein Disulfide

scholarly journals Protein disulfide isomerase activity is released by activated platelets

Blood ◽  
1992 ◽  
Vol 79 (9) ◽  
pp. 2226-2228 ◽  
Author(s):  
K Chen ◽  
Y Lin ◽  
TC Detwiler
Keyword(s):  
Disulfide Bonds ◽  
Protein Disulfide Isomerase ◽  
Ph Dependence ◽  
Gel Filtration ◽  
Disulfide Isomerase ◽  
Isomerase Activity ◽  
Activated Platelets ◽  
Protein Disulfide ◽  
Supernatant Solution ◽  
Disulfide Isomerase Activity

Abstract The release of protein disulfide isomerase by activated platelets was hypothesized on the basis of reported intermolecular and intramolecular thiol-disulfide exchange and disulfide reduction involving released thrombospondin in the supernatant solution of activated platelets (Danishefsky, Alexander, Detwiler: Biochemistry, 23:4984, 1984; Speziale, Detwiler: J Biol Chem, 265:17859, 1990; Speziale, Detwiler: Arch Biochem Biophys 286:546, 1991). Protein disulfide isomerase activity, measured by catalysis of the renaturation of ribonuclease inactivated by randomization of disulfide bonds, was detected in the supernatant solution after platelet activation. The activity was inhibited by peptides known to inhibit protein disulfide isomerase; the peptides also inhibited formation of disulfide-linked thrombospondin- thrombin complexes. The reaction catalyzed by the supernatant solution showed a pH dependence distinct from that of the uncatalyzed reaction. The activity was excluded by a 50-Kd dialysis membrane, and it was eluted in the void volume of a gel-filtration column, indicating that it was associated with a macromolecule. The activity was not removed by centrifugation at 100,000 g for 150 minutes indicating that it was not associated with membrane microvesicles. Possible functions for the release of protein disulfide isomerase by activated platelets are discussed.

scholarly journals Localization of protein disulfide isomerase to the external surface of the platelet plasma membrane

Blood ◽  
1995 ◽  
Vol 86 (6) ◽  
pp. 2168-2173 ◽  
Author(s):  
DW Essex ◽  
K Chen ◽  
M Swiatkowska
Keyword(s):  
Indirect Immunofluorescence ◽  
Blood Cells ◽  
Disulfide Bonds ◽  
Protein Disulfide Isomerase ◽  
Immunofluorescence Microscopy ◽  
External Surface ◽  
Platelet Surface ◽  
Disulfide Isomerase ◽  
Indirect Immunofluorescence Microscopy ◽  
Protein Disulfide

Protein disulfide isomerase (PDI) is an enzyme that catalyzes the formation as well as the isomerization of disulfide bonds. In this study, antibodies against PDI were used to show PDI antigen on the platelet surface by indirect immunofluorescence microscopy and by flow cytometry. The platelets were not activated, as evidenced by the absence of staining by an antibody against P-selectin. Permeabilized platelets showed little cytosolic PDI by indirect immunofluorescence microscopy, suggesting that the majority of platelet PDI is localized to the platelet surface. PDI activity against “scrambled” RNase was shown with intact platelets. The activity was inhibited by inhibitors of PDI and by an antibody against PDI. Other blood cells showed little PDI. Platelet surface PDI may play a role in the various physiological and pathophysiologic processes in which platelets are involved.

scholarly journals The anterior gradient-2 interactome

2020 ◽  
Vol 318 (1) ◽  
pp. C40-C47 ◽  
Author(s):  
Frederic Delom ◽  
M. Aiman Mohtar ◽  
Ted Hupp ◽  
Delphine Fessart
Keyword(s):  
Disulfide Bonds ◽  
Protein Disulfide Isomerase ◽  
Protein Quality ◽  
Physiological Role ◽  
Disulfide Isomerase ◽  
Cellular Effects ◽  
Binding Partners ◽  
Protein Disulfide ◽  
Biological Outcomes

The anterior gradient-2 (AGR2) is an endoplasmic reticulum (ER)-resident protein belonging to the protein disulfide isomerase family that mediates the formation of disulfide bonds and assists the protein quality control in the ER. In addition to its role in proteostasis, extracellular AGR2 is responsible for various cellular effects in many types of cancer, including cell proliferation, survival, and metastasis. Various OMICs approaches have been used to identify AGR2 binding partners and to investigate the functions of AGR2 in the ER and outside the cell. Emerging data showed that AGR2 exists not only as monomer, but it can also form homodimeric structure and thus interact with different partners, yielding different biological outcomes. In this review, we summarize the AGR2 “interactome” and discuss the pathological and physiological role of such AGR2 interactions.

scholarly journals Recurrent homozygous damaging mutation in TMX2, encoding a protein disulfide isomerase, in four families with microlissencephaly

2019 ◽  
Vol 57 (4) ◽  
pp. 274-282 ◽  
Author(s):  
Shereen Georges Ghosh ◽  
Lu Wang ◽  
Martin W Breuss ◽  
Joshua D Green ◽  
Valentina Stanley ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Protein Disulfide Isomerase ◽  
Transmembrane Protein ◽  
Repeat Expansion ◽  
Global Developmental Delay ◽  
Disulfide Isomerase ◽  
Whole Exome ◽  
Brain Malformations ◽  
Repeat Expansions ◽  
Protein Disulfide

BackgroundProtein disulfide isomerase (PDI) proteins are part of the thioredoxin protein superfamily. PDIs are involved in the formation and rearrangement of disulfide bonds between cysteine residues during protein folding in the endoplasmic reticulum and are implicated in stress response pathways.MethodsEight children from four consanguineous families residing in distinct geographies within the Middle East and Central Asia were recruited for study. All probands showed structurally similar microcephaly with lissencephaly (microlissencephaly) brain malformations. DNA samples from each family underwent whole exome sequencing, assessment for repeat expansions and confirmatory segregation analysis.ResultsAn identical homozygous variant in TMX2 (c.500G>A), encoding thioredoxin-related transmembrane protein 2, segregated with disease in all four families. This variant changed the last coding base of exon 6, and impacted mRNA stability. All patients presented with microlissencephaly, global developmental delay, intellectual disability and epilepsy. While TMX2 is an activator of cellular C9ORF72 repeat expansion toxicity, patients showed no evidence of C9ORF72 repeat expansions.ConclusionThe TMX2 c.500G>A allele associates with recessive microlissencephaly, and patients show no evidence of C9ORF72 expansions. TMX2 is the first PDI implicated in a recessive disease, suggesting a protein isomerisation defect in microlissencephaly.

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