αII-Spectrin , cleavage-specific Antibody

Spectrins are central components of the cytoskeleton that form a scaffold below the plasma membrane. Spectrins contain two subunits, α and β, which intertwine to form heterodimers that can self associate into elongated tetramers. α-spectrin I and β-spectrin I form heterodimers in red blood cells, while nonerythroid mammalian cells contain heterodimers of α-spectrin I and II with β-spectrin I to V. The structure of spectrins includes a succession of triple-helical repeats along with various domains, such as SH3 domain, EF hands, PH domains, and binding domains for ankyrin, actin, band 4.1, and calmodulin. α-spectrin II is a widely expressed non-erythroid spectrin that contains an SH3 domain, a calmodulin binding site, and two cleavage sites, one at Tyr-1176 for calpains and one at Asp-1185 for caspase-3. α-spectrin II and β-spectrin II, like many other spectrins, can form heterodimers that can self associate into tetramers, as well as interact with Band 4.1, F-actin, and other proteins near the plasma membrane.

The antibody detects a 136 kDa* cleaved fragment corresponding to αII-Spectrin on SDS-PAGE immunoblots of mouse diaphram treated with thapsigargin. The antibody only detects cleaved αII-Spectrin and does not detect full length αII-Spectrin. This sequence has high homology with similar regions in rat and mouse αII-spectrin, but is not found in other spectrin family members.