Related Experiment Video
Updated: Aug 19, 2026
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Antibody recognition of calcium-binding proteins depends on their calcium-binding status
1Laboratory of Clinical Science, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-1266, USA.
Abstract:
Previous studies have revealed changes in immunohistochemical stains for calcium-binding proteins after manipulations that influence intracellular calcium. Cases have been revealed in which these changes in immunoreactivity were not correlated with changes in protein amounts. The present experiments examined whether these effects might be explained by changes in antiserum recognition due to calcium-induced changes in protein conformation. Calretinin, calbindin D28k, and parvalbumin incubated in high calcium were recognized by antisera better than when they were incubated in low calcium. Using a calbindin D28k antibody, it was shown that this effect occurs within physiological calcium concentrations. Formalin fixation of the proteins in the presence of calcium resulted in greater antibody recognition than did fixation of proteins in calcium-free states. The calretinin antiserum appeared to recognize a portion of the molecule previously shown to undergo calcium-dependent conformational changes. A calcium-insensitive antiserum was made to a different fragment of calretinin. These results indicate that some antibodies to calcium-binding proteins preferentially recognize particular calcium-induced protein conformations. Given the potential for wide fluctuations in neuronal calcium, the present results indicate that quantitative estimates of intracellular calcium-binding proteins obtained from immunohistochemical studies of neurons must be interpreted with caution.
Related Concept Videos
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...
01:10Antibody 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...
01:16Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:17Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
01:21Skeleton and Calcium Homeostasis
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.