Related Experiment Video
Updated: Aug 8, 2026
Combined Immunofluorescence and DNA FISH on 3D-preserved Interphase Nuclei to Study Changes in 3D Nuclear Organization
Published on: February 3, 2013
Coordination of immunoglobulin chain folding and immunoglobulin chain assembly is essential for the formation of
1Institut für Biochemie I, Universität Heidelberg, Federal Republic of Germany.
Insights
The CH1 domain of immunoglobulin heavy chains is crucial for proper antibody assembly. Its interaction with BiP in the endoplasmic reticulum ensures correct folding and antigen binding.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- The CH1 domain of immunoglobulin heavy (H) chains is vital for retaining unassembled H chains in the endoplasmic reticulum (ER) via BiP interaction.
- Understanding the role of CH1 in H chain folding and assembly with light (L) chains is critical for antibody production.
Purpose of the Study:
- To investigate the role of the CH1 domain in BiP binding and its impact on immunoglobulin H and L chain assembly.
- To determine how CH1 domain mutations affect antibody folding, secretion, and antigen-binding capacity.
Main Methods:
- In vivo analysis of wild-type and mutant gamma H chains in reduced and oxidized states.
- Assessment of BiP binding to H chains under different redox conditions.
- Examination of H and L chain association, intracellular accumulation, and secretion in transfected cells.
- Evaluation of antigen-binding affinity of secreted antibodies.
Main Results:
- Both wild-type and CH1-deleted gamma H chains bind BiP when reduced.
- Oxidized mutant H chain dimers release from BiP, but oxidized wild-type gamma chain dimers remain bound.
- Mutant H chains lacking CH1 accumulate with L chains in ER vesicles and are secreted as partially functional IgG, with reduced antigen binding.
- Replacing CH1 with CH3 yields similar results, indicating CH1's unique role.
Conclusions:
- BiP interaction with incompletely folded CH1 domains is essential for the correct assembly of immunoglobulin H and L chains.
- Proper folding mediated by CH1-BiP interaction is necessary for functional antibody production and secretion.
Abstract:
The first constant domain (CH1) of immunoglobulin heavy (H) chains is essential for BiP-mediated retention of unassembled H chains in the endoplasmic reticulum (ER). Here, we demonstrated that both wild-type and a mutant gamma chain lacking the CH1 domain bind BiP when they are reduced in vivo. However, only oxidized mutant H chain dimers are released from BiP interaction, whereas oxidized wild-type gamma chain dimers still bind BiP. In light (L) chain-producing cells, some of the mutant H chains accumulate with L chains in ER-derived vesicles and some are secreted as IgG. Furthermore, only half of the secreted antibodies bind antigen. We found the same with a mutant gamma chain, in which the CH1 domain was replaced by a CH3 domain. Therefore, we propose that BiP interaction with incompletely folded CH1 domains is required to mediate correct assembly of H and L chains.
Related Concept Videos
01:22Protein Folding
01:10Antibody Structure
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
01:22Protein Folding
01:10Antibody Structure
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
01:25Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
01:25Antibody Structure and Classes
The basic structure of an antibody consists of four protein chains: two identical heavy chains and two identical light chains. These chains are held together by disulfide bonds and other non-covalent interactions, forming a Y-shaped structure.