RCAN1/Dscr1 (C-terminus) Antibody

An important element of calcium signaling pathways involves calmodulin activation of calcineurin (phosphatase PP2B), leading to dephosphorylation of transcription factors such as NFAT and MEF2. A wide variety of proteins other than calmodulin have also been implicated in regulating calcineurin activity. Regulators of Calcineurin (RCANs) include RCAN1, RCAN2, and RCAN3. RCAN1 has previously been referred to as Down's syndrome candidate region-1 (Dscr1), MCIP, calcipressin, and Adapt78. This RCAN is expressed as several different variants with RCAN1L (38 kDa) and RCAN1S (31 kDa) being most prevalent. RCAN1 is increased in Down's syndrome tissues and in a mouse model of Down's syndrome. Increased expression of RCAN1 leads to significant suppression of tumor growth in mice as result of deficits in calcineurin-induced tumor angiogenesis. RCAN1 can recruit TAB1, TAK1, and calcineurin into a macromolecular signaling complex, and TAK1 can phosphorylate Ser-94 and Ser-136 in RCAN1S. This phosphorylation converts RCAN1 from an inhibitor to a facilitator of calcineurin-NFAT signaling.

The antibody detects several isoforms of RCAN1 on SDS-PAGE immunoblots of adult mouse muscle and brain, rat PC12 cells, and human A431 and Jurkat cells. The predominate isoforms detected were the 38 kDa RCAN1L and 31 kDa RCAN1S. This sequence is highly conserved in rat and mouse RCAN1, and this sequence is found in all four isoforms of RCAN1, but is not found in RCAN2 or RCAN3.