CREB (Ser-271), Phosphospecific Antibody

CREB (cyclic AMP response element-binding protein) is a stimulus-induced transcription factor that plays pivotal roles in cell survival and proliferation. CREB is expressed in various tissues, and has important gene-regulating roles in the nervous system. The transactivation function of CREB is primarily regulated through Ser-133 phosphorylation by cAMP-dependent protein kinase A (PKA) and related kinases. CREB is phosphorylated at other sites in response to calcium influx and DNA damage. The DNA-damage responsive nuclear kinase, HIPK2, can phosphorylate Ser-271 but not Ser-133 in CREB, and this phosphorylation activates CREB transactivation function. Mutation of Ser-271 to Glu-271 potentiates the CREB transactivation function. Thus, phosphorylation of Ser-271 may be the mode of activation for CREB-dependent transcription in response to genotoxic stress.

The antibody detects a 43 kDa* protein corresponding to the molecular mass of CREB on SDS-PAGE immunoblots of human A431, Jurkat, and rat PC12 cells treated with Calyculin A, but is not observed after lambda phosphatase treatment. The site has some homology to the conserved site in ATF1 (Ser-198) and CREM (Ser-287) . This sequence is well conserved in rat, mouse, chicken, and zebrafish CREB.