Calbindin, mouse monoclonal, Cat# MCA-5A9

Calbindin, mouse monoclonal, Cat# MCA-5A9



Adult mouse cortex (Left) and cerebellum (Right) sections were stained with MCA-5A9 in red, and co-stained with our rabbit polyclonal anti-Fox3/NeuN antibody (RPCA-Fox3) in green. Calbindin is expressed in a subset of interneurons in the cortex (Left) and prominently expressed in the dendrites of Purkinje cells in the cerebellum molecular layer (Right). Fox3/NeuN expresses in most neurons; as a result, cells positive for calbindin appear to be yellow. Insets are high magnification images of the boxed area. Blue is Dapi nucleus staining that labels DNA.

Western blot analysis of MCA-5A9. Blots of cow cerebellum lysate were probed with MCA-5A9. The MCA-5A9 monoclonal binds strongly and cleanly to the calbindin band at 28 kDa.

Product name Anti Calbindin
Description Mouse Monoclonal to Calbindin
Reference Code MCA-5A9
HGNC name CALB1
RRID# AB_2572239
Molecular weight 28 kDa
Immunogen Full length recombinant human protein
Isotype IgG2a
Concentration Antibody is supplied as an aliquot of 1 mg/mL of affinity purified antibody
Species Reactivity Human, horse, cow, pig, chicken, rat, mouse
Applications Western blot, ICC/IF, IHC
Suggestions for use Western blots: 1:5,000.
ICC/IF or IHC: 1:5,000.


Calbindin, also known as calbindin 1 or calbindin-D28k is a member of the large superfamily of cytoplasmic Ca2+ binding proteins. Calbindin-1 belongs to the subclass of these containing the “EF hand” Ca2+ binding motif originally characterized in parvalbumin (1). Calbindin is expressed in the brain, intestine, kidney and pancreas. In the brain it is localized in certain classes of neurons, and antibodies to it are useful for identifying specific neuronal cell types (2). It is particularly concentrated in the dendrites and perikarya of cerebellar Purkinje cells, but is also found in many GABAergic interneurons in the cortex. These GABAergic interneurons in most cases express only one of three Ca2+ binding proteins, namely calbindin or parvalbumin or calretinin. As a result these important inhibitory interneurons can be identified and subclassified based on their content of these three proteins (2). Each type of neuron as defined in this fashion has particular electrophysiological and functional properties. For example, calbindin positive interneurons are not fast-spiking as are parvalbumin expressing interneurons. Human calbindin is a 263 amino acid protein with an SDS-PAGE weight of 28 kDa. It is related in primary sequence to calretinin, which is also known as 29 kDa calbindin and calbindin-2. The primary sequence and NMR structure of calbindin indicates six distinct Ca2+ binding sites corresponding to the EF hands motifs. Of the six sites four bind Ca2+ with relatively high affinity. The function of calbindin-1 appears to be primarily buffering the Ca2+ level in cells. The affinity of calbindin for Ca2+ is low at the typical resting cytoplasmic Ca2+ level of around 100nM, and the protein only binds Ca2+ significantly when levels increase greatly. Accordingly it is widely thought that the primary function of this protein is to act as a Ca2+ buffer. Buffering Ca2+ is important, as uncontrolled increases in the level of this ion can lead to both apoptosis due to Ca2+ stimulated release of proteins from mitochondria and necrosis due to the activation of Ca2+ dependent proteases. Knockout of the calbindin-1 gene in mice leads to ataxia and other motor problems, consistent with the large amounts of this protein normally present in the cerebellum (3). The HGNC name for this protein is CALB1.


References:

1. Kretsinger RH & Nockolds CE. Carp Muscle Calcium-binding Protein: II. Structure determination and general description. J. Biol. Chem. 248:3313-3326 (1973).

2. Andressen C, Bliimcke I & Celio MR. Calcium-binding proteins: selective markers of nerve cells. Cell Tissue Res 271:181-208 (1993).

3. Schwaller B, Meyer M & Schiffmann S. ‘New’ functions for ‘old’ proteins: The role of the calcium binding proteins calbindin D-28k, calretinin and parvalbumin, in cerebellar physiology. Studies with knockout mice. The Cerebellum 1:241–258 (2002).

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