Chicken Polyclonal Antibody to Calretinin
Cat# CPCA-Calret

Calretinin, as the name suggests, was originally isolated in the retina but was found to be also expressed in mammalian central nerve system, testis, fallopian tube and pancreas (1). It is a cytoplasmic Calcium binding protein which includes typical “EF hand” structures the prototype for which is the protein parvalbumin (2-4). In the brain calretinin it is localized in certain classes of neurons, and antibodies to it are useful for identifying specific neuronal cell types (1). It is particularly concentrated in some cerebellar granular cells and their parallel fibres, but is also found in many GABAergic interneurons in the cortex. These GABAergic interneurons in most cases express only one of three related Calcium binding proteins, namely calretinin, calbindin or parvalbumin (5,6). As a result these important inhibitory interneurons can be identified and classified based on their content of these three proteins. Each type of neuron as defined in this fashion has distinct electrophysiological and functional properties (7). Calretinin deficiency in the mossy cells of the mouse dentate gyrus and granule cells results in abnormal excitability in the cerebellar neuronal network and impairment of long-term potentiation and motor coordination, suggesting that calretinin functions as a general Calcium buffer (8).
The CPCA-Calret antibody was made against full length recombinant human calretinin expressed in and purified from E. coli. The calretinin protein is related in amino acid sequence to calbindin and to a lesser extent parvalbumin, so, for studies of GABAergic interneurons, it is important to verify that antibodies developed against one protein do not cross react with either of the others, which we have done for MCA-3G9 using appropriate recombinant human proteins. We manufacture mouse monoclonal antibodies to calretinin MCA-3G9 and MCA-6A9, and a rabbit polyclonal antibody RPCA-Calret. We also supply a variety of other mouse, rabbit and chicken antibodies to calbindin (MCA-4H7, MCA-5A9 and CPCA-Calb) and parvalbumin (MCA-3C9 and CPCA-Pvalb), allowing double and triple labeling of appropriate cell and tissue samples. Mouse select image at left for larger view.