Creb Phospho-s133 Kit - 50,000 Tests.The phospho-CREB (S133) kit is optimal for the quantitative detection of the cyclic AMP-responsive element-binding protein when phosphorylated at S133, thus enabling the phosphorylation status of CREB to be checked with respect to its steady-state level in cells. CREB functions as a transcription factor, signaling downstream from MAPK/ERK and activated by several pathways, such as MAPK/ERK, PI3K/AKT and stress signaling. CREB plays a critical role in promoting neuronal plasticity, cognitive abilities, cell proliferation, survival, and glucose homeostasis..