Anti-Caspr2 Antibody, extracellular domain

Contactin-associated protein-like 2 (UniProt Q9UHC6; also known as Cell recognition molecule Caspr2) is encoded by the CNTNAP2 (also known as AUTS15, CASPR2, CDFE, KIAA0868) gene (Gene ID 26047) in human. Caspr2 is a neurexin superfamily member that functions as a neuronal cell adhesion protein. Originally identified in myelinating nerves, Caspr2 serves to cluster voltage-gated potassium (Kv) channels at the juxtaparanode, a membrane domain adjacent to the node of Ranvier, where it forms a barrier holding nodal components in place. Caspr2 is found in axons, dendrites, dendritic spines and the soma of mature pyramidal neurons in the central nervous system (CNS). Caspr2 and its partner Contactin 2 are found in the synaptic plasma membranes fraction of the forebrain. In the absence of Caspr2, new synaptic spines are unable to stabilize, resulting in decreased spine density and altered spine morphology as well as downregulated AMPA receptor subunit on the spines in mice. CNTNAP2 gene mutations are linked to autism spectrum disorder (ASD) in human. Likewise, Cntnap2-knockout mice exhibit core autism-like deficits including abnormal social behavior and communication, and behavior inflexibility. Caspr2 is produced with a signal peptide (a.a. 1-27), the removal of which yields the mature transmembrane proein with a large extracellular region (a.a. 28-1262), followed by a transmembrane domain (a.a. 1263-1283) and a cytoplasmic tail (human a.a. 1284-1331 and mouse a.a. 1284-1332). The extracellular region contains an N-terminal Discoidin domain (a.k.a. F5/8 type C domain or C2-like domain; human a.a. 35-181), four Laminin G-like domains (human a.a. 216-368, 401-552, 799-963, 1055-1214), two EGF-like domains (human a.a. 554-591 and 963-1002), and a Fibrinogen C-terminal domain (human a.a. 592-798).

~180 kDa observed. Target band size appears larger than the calculated molecular weights of 156.3 kDa (human & mouse pro-form) and 154.3/154.2 kDa (human/mouse mature form) due to glycosylation. Uncharacterized bands may be observed in some lysate(s).

Epitope: extracellular domain

Human IgG1 Fc-tagged recombinant human Caspr2 extracellular domain fragment.

Anti-Caspr2 Antibody, extracellular domain, Cat. No. ABN1380, is a highly specific rabbit polyclonal antiserum that targets Caspr2 and has been tested in Immunocytochemistry and Western Blotting.

Immunocytochemistry Analysis: A 1:1000 dilution from a representative lot detected Caspr2 immunoreactivity at the juxtaparanodal region around the nodes of Ranvier by indirect immunofluorescent staining of 0.5% Triton X-100-permeabilized teased fibers prepared from 4% paraformaldehyde-fixed, desheathed wild-type, but not Caspr2-knockout, mouse sciatic nerves (Courtesy of Dr. Elior Peles, Weizmann Institute of Science, Rehovot, Israel).

Immunocytochemistry Analysis: A representative lot detected Caspr2 immunoreactivity at the juxtaparanodal region around the nodes of Ranvier by indirect immunofluorescent staining of teased fibers prepared from paraformaldehyde-fixed, desheathed wild-type, but not Caspr2-knockout, mouse sciatic nerves (Gordon, A., et al. (2015). Mol. Cell. Sci. In press).

Western Blotting Analysis: A representative lot detected a lower Caspr2 level in brain tissue lysates from mice with heterozygous Caspr2-knockout than wild-type mice, while no Caspr2 expression was detected in brain samples from mice with homozygous Caspr2-knockout (Gordon, A., et al. (2015). Mol. Cell. Sci. In press).

Research Category
Neuroscience

Specificity of this polyclonal antiserum was confirmed by the lack of target detection when using tissue samples from Capr2 knock-out mice. This polyclonal antiserum targets extracellular region absent from human Caspr2 spliced isoform 2 (Uniprot Q9UHC6-2).

Rabbit polyclonal antibody serum with 0.05% sodium azide.

Unpurified.

Stable for 1 year at -20°C from date of receipt.
Handling Recommendations: Upon receipt and prior to removing the cap, centrifuge the vial and gently mix the solution. Aliquot into microcentrifuge tubes and store at -20°C. Avoid repeated freeze/thaw cycles, which may damage IgG and affect product performance.

Evaluated by Western Blotting in mouse brain tissue lysate.

Western Blotting Analysis (WB): A 1:5000 dilution of this antibody detected Caspr2 in 10 µg of mouse brain tissue lysate.

Concentration: Please refer to lot specific datasheet.

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