WEE1 and cancer: Using a phospho-specific antibody in combination with specific siRNAs and protein kinase inhibitors together with cells derived from mice deficient for MK2 and MK3 expression, we found that S857 is phosphorylated by MK2 in response to activation of the p38MAPK signaling pathway in several human cancer cells, as well as in mouse embryonal fibroblast and bone marrow derived mouse cells.