Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Molecular Chaperones and Protein Folding03:00

Molecular Chaperones and Protein Folding

18.2K
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
18.2K
Protein Folding01:25

Protein Folding

8.3K
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
8.3K
Bacterial Protein Maturation01:26

Bacterial Protein Maturation

66
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...
66
Post-translational Translocation of Proteins to the RER01:27

Post-translational Translocation of Proteins to the RER

5.8K
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
5.8K
Protein Folding Quality Check in the RER01:29

Protein Folding Quality Check in the RER

3.8K
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
3.8K
Cotranslational Protein Translocation01:20

Cotranslational Protein Translocation

7.5K
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
7.5K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Site-specific labeling uncovers differences in levels and distribution of B-cell receptors of different isotypes on primary B cells.

Journal of immunology (Baltimore, Md. : 1950)·2025
Same author

Transmembrane Helices 7 and 8 Confer Aggregation Sensitivity to the Cystic Fibrosis Transmembrane Conductance Regulator.

International journal of molecular sciences·2023
Same author

Neil J. Bulleid (1960-2023), a virtuoso of protein folding and redox biology.

The EMBO journal·2023
Same author

ABC-transporter CFTR folds with high fidelity through a modular, stepwise pathway.

Cellular and molecular life sciences : CMLS·2023
Same author

Redefining Hypo- and Hyper-Responding Phenotypes of CFTR Mutants for Understanding and Therapy.

International journal of molecular sciences·2022
Same author

Induction of antigen-specific tolerance by nanobody-antigen adducts that target class-II major histocompatibility complexes.

Nature biomedical engineering·2021

Related Experiment Video

Updated: Aug 23, 2025

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase
08:59

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase

Published on: February 12, 2019

11.3K

Hold the fold: how delayed folding aids protein secretion.

Nicholas McCaul1, Ineke Braakman2

  • 1Department of Biological and Geographical Sciences, School of Applied Sciences, University of Huddersfield, Huddersfield, UK.

The EMBO Journal
|October 31, 2022
PubMed
Summary

Researchers studied protein transport in bacteria by observing structural twins. This research reveals how evolution has optimized the bacterial secretory pathway for efficient protein translocation across membranes.

More Related Videos

4D Imaging of Protein Aggregation in Live Cells
08:59

4D Imaging of Protein Aggregation in Live Cells

Published on: April 5, 2013

17.5K
Using Caenorhabditis elegans as a Model System to Study Protein Homeostasis in a Multicellular Organism
12:38

Using Caenorhabditis elegans as a Model System to Study Protein Homeostasis in a Multicellular Organism

Published on: December 18, 2013

6.2K

Related Experiment Videos

Last Updated: Aug 23, 2025

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase
08:59

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase

Published on: February 12, 2019

11.3K
4D Imaging of Protein Aggregation in Live Cells
08:59

4D Imaging of Protein Aggregation in Live Cells

Published on: April 5, 2013

17.5K
Using Caenorhabditis elegans as a Model System to Study Protein Homeostasis in a Multicellular Organism
12:38

Using Caenorhabditis elegans as a Model System to Study Protein Homeostasis in a Multicellular Organism

Published on: December 18, 2013

6.2K

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Bacteria utilize N-terminal signal peptides to direct proteins for secretion across the plasma membrane.
  • The efficiency of the bacterial secretory pathway is crucial for cell function and survival.
  • Understanding protein transport mechanisms provides insights into fundamental biological processes.

Purpose of the Study:

  • To investigate the folding dynamics of signal peptides during protein transport.
  • To elucidate how evolutionary optimization has shaped the bacterial secretory process.
  • To analyze the role of structural features in protein translocation efficiency.

Main Methods:

  • Utilized a pair of "structural twins" – proteins with similar structures but different sequences – to compare folding and transport.
  • Employed advanced imaging techniques to observe protein folding in real-time.
  • Applied computational modeling to analyze the forces governing protein translocation.

Main Results:

  • Observed distinct folding pathways for the structural twins, highlighting sequence-specific influences.
  • Identified key intermediate states during signal peptide folding that facilitate membrane passage.
  • Demonstrated that evolutionary modifications optimize the speed and fidelity of protein secretion.

Conclusions:

  • The study provides novel insights into the co-evolution of signal peptides and the secretory machinery.
  • Findings suggest that subtle sequence variations can lead to significant functional differences in protein transport.
  • This work deepens our understanding of how bacteria have evolved efficient protein export systems.