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

Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial precursors...
pre-mRNA Processing02:01

pre-mRNA Processing

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Pre-mRNA Processing02:01

Pre-mRNA Processing

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl guanosine). This 5’ cap helps the...
Pre-mRNA Processing: Modification of pre-mRNA Ends01:35

Pre-mRNA Processing: Modification of pre-mRNA Ends

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
Antigen Processing Pathways01:31

Antigen Processing Pathways

MHC molecules are key players in the immune response, enabling T cells to recognize and respond to specific antigens. They are present on the surface of all nucleated cells in the body and are instrumental in presenting antigens to T cells and activating them. T cells recognize the MHC-antigen complex and initiate an immune response. MHC class I and MHC class II are two main types of MHC molecules, each associated with a distinct antigen processing pathway.
MHC Class I: Presenting Endogenous...
The Proteasome Structure01:17

The Proteasome Structure

The ubiquitin-proteasome pathway is a well-known mechanism utilized by eukaryotic cells to remove cytoplasmic proteins that are misfolded, damaged, or no longer needed. In this pathway, the protein that needs to be eliminated undergoes a process called ubiquitination, where a chain of ubiquitin molecules is attached to the 48th lysine residue of the target protein. This ubiquitin modification helps the proteasome distinguish between a target protein and a healthy protein.
The proteasome is an...

You might also read

Related Articles

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

Sort by
Same author

Preservation of Reduced Numbers of Insulin-Positive Cells in Sulfonylurea-Unresponsive KCNJ11-Related Diabetes.

The Journal of clinical endocrinology and metabolism·2016
Same author

Protective hinge in insulin opens to enable its receptor engagement.

Proceedings of the National Academy of Sciences of the United States of America·2014
Same author

Genetic complexity in a Drosophila model of diabetes-associated misfolded human proinsulin.

Genetics·2013
Same author

Autoimmunity against INS-IGF2 protein expressed in human pancreatic islets.

The Journal of biological chemistry·2013
Same author

How insulin engages its primary binding site on the insulin receptor.

Nature·2013
Same author

Biosynthesis of proTRH-derived peptides in prohormone convertase 1 and 2 knockout mice.

Peptides·2012

Related Experiment Video

Updated: May 30, 2026

Analysis of Transforming Growth Factor ß Family Cleavage Products Secreted Into the Blastocoele of Xenopus laevis Embryos
06:57

Analysis of Transforming Growth Factor ß Family Cleavage Products Secreted Into the Blastocoele of Xenopus laevis Embryos

Published on: July 21, 2021

On the discovery of precursor processing.

Donald F Steiner1

  • 1Department of Biochemistry, The University of Chicago, Chicago, IL 60637, USA. dfsteine@uchicago.edu

Methods in Molecular Biology (Clifton, N.J.)
|August 2, 2011
PubMed
Summary
This summary is machine-generated.

The discovery of insulin precursor "proinsulin" revealed a new biological pathway. This finding identified a proteolytic processing system crucial for hormone biosynthesis and secretion.

More Related Videos

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker
08:12

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker

Published on: January 3, 2019

Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient
08:30

Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient

Published on: September 17, 2011

Related Experiment Videos

Last Updated: May 30, 2026

Analysis of Transforming Growth Factor ß Family Cleavage Products Secreted Into the Blastocoele of Xenopus laevis Embryos
06:57

Analysis of Transforming Growth Factor ß Family Cleavage Products Secreted Into the Blastocoele of Xenopus laevis Embryos

Published on: July 21, 2021

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker
08:12

Single-step Purification of Macromolecular Complexes Using RNA Attached to Biotin and a Photo-cleavable Linker

Published on: January 3, 2019

Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient
08:30

Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient

Published on: September 17, 2011

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Endocrinology

Background:

  • Early studies in human insulinoma and rat islets investigated insulin biosynthesis.
  • These studies aimed to understand the mechanisms behind insulin production and secretion.

Observation:

  • A rapidly labeled precursor, designated proinsulin, was identified before insulin.
  • Proinsulin is converted to insulin via proteolytic processing within secretory granules.
  • Structural analysis revealed proinsulin as a single polypeptide chain with A and B chains linked by a C-peptide.

Findings:

  • Paired basic residues at cleavage sites were identified for C-peptide excision.
  • Human proinsulin and C-peptide sequencing enabled the development of a C-peptide assay.
  • This assay indirectly measures insulin levels, particularly useful for diabetics.

Implications:

  • The insulin precursor model served as a paradigm for other peptide hormone biosynthesis.
  • Discovery of yeast processing pathways led to identification of eukaryotic endopeptidases (e.g., PC1/3, PC2) and exopeptidases (e.g., CPE).
  • These enzymes are critical for neuroendocrine peptide processing in the secretory pathway.