Catalysis of disulphide bond formation in the endoplasmic reticulum

2004 ◽  
Vol 32 (5) ◽  
pp. 663-667 ◽  
Author(s):  
L. Ellgaard
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Interactions ◽  
Protein Misfolding ◽  
Mammalian Cells ◽  
Specific Protein ◽  
Surface Proteins ◽  
Redox Conditions ◽  
Protein Protein Interactions ◽  
Disulphide Bonds ◽  
Correct Pairing

Disulphide bonds are critical for the maturation and stability of secretory and cell-surface proteins. In eukaryotic cells, disulphide bonds are introduced in the ER (endoplasmic reticulum), where the redox conditions are optimal to support their formation. Yet, the correct pairing of cysteine residues is not simple and often requires the assistance of redox-active proteins. The enzymes of the thiol-disulphide oxidoreductase family catalyse oxidation, reduction and isomerization, and thereby play important roles for the folding of many proteins. To allow all three redox reactions to take place concurrently in the same compartment, specific protein–protein interactions regulate the function of individual enzymes, while a careful balance of the ER redox environment is maintained. At the same time, the system must be capable of responding to changes in the cellular conditions, caused, for instance, by oxidative stress and protein misfolding. This review presents recent progress in understanding how ER redox conditions are regulated and how protein disulphides are formed in the ER of mammalian cells.

scholarly journals Time-gated detection of protein-protein interactions with transcriptional readout

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Min Woo Kim ◽  
Wenjing Wang ◽  
Mateo I Sanchez ◽  
Robert Coukos ◽  
Mark von Zastrow ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Mammalian Cells ◽  
High Specificity ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
High Background ◽  
Specificity And Sensitivity ◽  
Time Courses ◽  
Rapid Kinetics ◽  
Two Hybrid

Transcriptional assays, such as yeast two-hybrid and TANGO, that convert transient protein-protein interactions (PPIs) into stable expression of transgenes are powerful tools for PPI discovery, screens, and analysis of cell populations. However, such assays often have high background and lose information about PPI dynamics. We have developed SPARK (Specific Protein Association tool giving transcriptional Readout with rapid Kinetics), in which proteolytic release of a membrane-tethered transcription factor (TF) requires both a PPI to deliver a protease proximal to its cleavage peptide and blue light to uncage the cleavage site. SPARK was used to detect 12 different PPIs in mammalian cells, with 5 min temporal resolution and signal ratios up to 37. By shifting the light window, we could reconstruct PPI time-courses. Combined with FACS, SPARK enabled 51 fold enrichment of PPI-positive over PPI-negative cells. Due to its high specificity and sensitivity, SPARK has the potential to advance PPI analysis and discovery.

scholarly journals A yeast DnaJ homologue, Scj1p, can function in the endoplasmic reticulum with BiP/Kar2p via a conserved domain that specifies interactions with Hsp70s.

1995 ◽  
Vol 129 (4) ◽  
pp. 979-988 ◽  
Author(s):  
G Schlenstedt ◽  
S Harris ◽  
B Risse ◽  
R Lill ◽  
P A Silver
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Interactions ◽  
Transmembrane Protein ◽  
Specific Protein ◽  
The Other ◽  
Eukaryotic Cells ◽  
Protein Protein Interactions ◽  
Similar Region ◽  
Conserved Domain ◽  
J Domain

Eukaryotic cells contain multiple Hsp70 proteins and DnaJ homologues. The partnership between a given Hsp70 and its interacting DnaJ could, in principle, be determined by their cellular colocalization or by specific protein-protein interactions. The yeast SCJ1 gene encodes one of several homologues of the bacterial chaperone DnaJ. We show that Scj1p is located in the lumen of the endoplasmic reticulum (ER), where it can function with Kar2p (the ER-lumenal BiP/Hsp70 of yeast). The region common to all DnaJ homologues (termed the J domain) from Scj1p can be swapped for a similar region in Sec63p, which is known to interact with Kar2p in the ER lumen, to form a functional transmembrane protein component of the secretory machinery. Thus, Kar2p can interact with two different DnaJ proteins. On the other hand, J domains from two other non-ER DnaJs, Sis1p and Mdj1p, do not function when swapped into Sec63p. However, only three amino acid changes in the Sis1p J domain render the Sec63 fusion protein fully functional in the ER lumen. These results indicate that the choice of an Hsp70 partner by a given DnaJ homologue is specified by the J domain.

scholarly journals The COP9 signalosome: at the interface between signal transduction and ubiquitin-dependent proteolysis

2002 ◽  
Vol 115 (3) ◽  
pp. 467-473 ◽  
Author(s):  
Dawadschargal Bech-Otschir ◽  
Michael Seeger ◽  
Wolfgang Dubiel
Keyword(s):  
Cell Cycle ◽  
Signal Transduction ◽  
Transcription Factors ◽  
Protein Interactions ◽  
Mammalian Cells ◽  
Specific Protein ◽  
26S Proteasome ◽  
Cop9 Signalosome ◽  
Protein Protein Interactions ◽  
Ubiquitin System

Recently the COP9 signalosome (CSN) has become a focus of interest for many researchers, because of its function at the interface between signal transduction and ubiquitin-dependent proteolysis. It is required for the proper progression of the cell cycle in Schizosaccharomyces pombe and is essential for development in plants and Drosophila. However, its function in mammalian cells remains obscure. Although the CSN shares structural similarities with the 26S proteasome lid complex (LID), its functions seem to be different from that of the LID. A variety of CSN-specific protein-protein interactions have been described in mammalian cells. However,it is currently unclear how many reflect true functions of the complex. Two activities associated with the CSN have been identified so far: a protein kinase and a deneddylase. The CSN-associated kinase phosphorylates transcription factors, which determines their stability towards the ubiquitin system. The associated deneddylase regulates the activity of specific SCF E3 ubiquitin ligases. The CSN thus appears to be a platform connecting signalling with proteolysis.

Defining the protein–protein interactions of the mammalian endoplasmic reticulum oxidoreductases (EROs)

2005 ◽  
Vol 33 (6) ◽  
pp. 1382-1384 ◽  
Author(s):  
S. Dias-Gunasekara ◽  
A.M. Benham
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Folding ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Plasma Membrane Proteins ◽  
Protein Disulphide Isomerase ◽  
Oxidative Protein Folding ◽  
Disulphide Bonds

The ER (endoplasmic reticulum) is the site of protein folding for all eukaryotic secreted and plasma membrane proteins. Disulphide bonds are formed in many of these proteins through a dithiol–disulphide exchange chain comprising two types of protein catalysts: PDI (protein disulphide-isomerase) and ERO (ER oxidoreductase) proteins. This review will examine what we know about ERO function, and will then consider ERO interactions and their implications for mammalian oxidative protein folding.

IL-14 MAPPIT: a versatile METHOD to study protein-protein interactions in mammalian cells

2003 ◽  
Vol 16 (5) ◽  
pp. 577-577
Author(s):  
J. Tavernier ◽  
S. Eyckerman ◽  
I. Lemmens ◽  
S. Lievens ◽  
J. Vandekerckhove ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Mammalian Cells ◽  
Protein Protein Interactions

Structure, Function, Involvement in Diseases and Targeting of 14-3-3 Proteins: An Update

2018 ◽  
Vol 25 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Ylenia Cau ◽  
Daniela Valensin ◽  
Mattia Mori ◽  
Sara Draghi ◽  
Maurizio Botta
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
Cellular Processes ◽  
Protein Partners ◽  
High Sequence Homology ◽  
Small Molecule Modulators

14-3-3 is a class of proteins able to interact with a multitude of targets by establishing protein-protein interactions (PPIs). They are usually found in all eukaryotes with a conserved secondary structure and high sequence homology among species. 14-3-3 proteins are involved in many physiological and pathological cellular processes either by triggering or interfering with the activity of specific protein partners. In the last years, the scientific community has collected many evidences on the role played by seven human 14-3-3 isoforms in cancer or neurodegenerative diseases. Indeed, these proteins regulate the molecular mechanisms associated to these diseases by interacting with (i) oncogenic and (ii) pro-apoptotic proteins and (iii) with proteins involved in Parkinson and Alzheimer diseases. The discovery of small molecule modulators of 14-3-3 PPIs could facilitate complete understanding of the physiological role of these proteins, and might offer valuable therapeutic approaches for these critical pathological states.

Oxidative protein folding in the mammalian endoplasmic reticulum

2004 ◽  
Vol 32 (5) ◽  
pp. 655-658 ◽  
Author(s):  
C.E. Jessop ◽  
S. Chakravarthi ◽  
R.H. Watkins ◽  
N.J. Bulleid
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Redox State ◽  
Structure And Function ◽  
Reduced Form ◽  
Secretory Proteins ◽  
Oxidative Protein Folding ◽  
Disulphide Bonds ◽  
And Function ◽  
Substrate Proteins

Native disulphide bonds are essential for the structure and function of many membrane and secretory proteins. Disulphide bonds are formed, reduced and isomerized in the endoplasmic reticulum of mammalian cells by a family of oxidoreductases, which includes protein disulphide isomerase (PDI), ERp57, ERp72, P5 and PDIR. This review will discuss how these enzymes are maintained in either an oxidized redox state that allows them to form disulphide bonds in substrate proteins or a reduced form that allows them to perform isomerization and reduction reactions, how these opposing pathways may co-exist within the same compartment and why so many oxidoreductases exist when PDI alone can perform all three of these functions.

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