Related Concept Videos
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...
01:31Regulation of the Unfolded Protein Response
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
02:24Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
01:29Translational Regulation
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
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Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
Thioredoxin-1 and posttranslational modifications.
1Molecular Cardiology, Department of Internal Medicine III, University of Frankfurt, Frankfurt, Germany. j.haendeler@em.uni-frankfurt.de
Antioxidants & Redox Signaling
|September 22, 2006
Summary
Thioredoxin-1 (TXN1) is a key protein regulating cell functions through its active cysteines. Posttranslational modifications, especially at nonactive cysteines, significantly impact TXN1
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- Thioredoxin-1 (TXN1) is a conserved 12 kDa protein essential for redox regulation.
- It possesses antioxidative, anti-apoptotic, and pro-proliferative functions.
- Mammalian TXN1 has unique nonactive cysteine residues distinct from lower species.
Purpose of the Study:
- To review the posttranslational modifications (PTMs) of TXN1.
- To elucidate the regulatory roles of PTMs at both active and nonactive cysteine residues.
- To understand how PTMs contribute to TXN1's diverse biological functions.
Main Methods:
- Literature review of TXN1 structure and function.
- Analysis of PTMs including glutathionylation, thiol-oxidation, and S-nitrosylation.
Main Results:
- Active cysteines (32 and 35) are crucial for TXN1 redox activity, reduced by thioredoxin reductase.
- Nonactive cysteines (62, 69, 73 in human TXN1) are sites for regulatory PTMs.
- PTMs at nonactive cysteines modulate TXN1's antioxidative, anti-apoptotic, and pro-proliferative activities.
Conclusions:
- PTMs of TXN1, particularly at nonactive cysteines, are critical for its functional regulation.
- Understanding these modifications provides insights into cellular redox homeostasis and disease.
- TXN1 PTMs represent a significant layer of control over its biological roles.