Anti-DARPP-32 Antibody, clone 9B6.1 clone 9B6.1, from mouse

Protein phosphatase 1 regulatory subunit 1B (EC 3.1.3.16; UniProt Q9UD71; also known as DARPP-32, Dopamine- and cAMP-regulated neuronal phosphoprotein 32) is encoded by the PPP1R1B (also known as DARPP32) gene (Gene ID 84152) in human. DARPP-32 is a PKA substrate that, upon phosphorylation on Thr34 by PKA, functions as a protein-phosphatase 1 (PP1) inhibitor. DARPP-32 N-terminal a.a. 8-11 (KIQF) is essential for PPI binding. DARPP-32 is an important mediator of dopamine receptor-dependent NMDA receptor activation. Dopamine receptor activation leads to cAMP induction, which activates cellular PKA activity and subsequent DARPP-32 Thr34 phosphorylation. PP1 inhibition by the Thr34 phosphorylated DARPP-32 in turn results in an enhnaced NMDA receptor phosphorylation. Calcium/calmodulin-dependent protein phosphatase 2B (PP2B or calcineurin) can reverse DARPP-32 Thr34 phosphorylation and negatively regulate its PP1 inhibitory activity. DARPP-32 is also known to be phosphorylated on Ser137 by casein kinase I (CKI), on Ser102 by CKII, and on Thr75 by Cdk5. Ser137 phosphorylation prevents PP2B from dephosphorylating pSer34, and Ser102 phosphorylation promotes Thr34 phosphorylation by PKA. Thr75 phosphorylated DARPP-32 is reported to exhibit PKA inhibitory activity in vitro.