Our study explores the phosphorylation pathways in decidualization, focussing on four major targets of interest – cAMP-dependent protein kinase, Rho-dependent protein kinase (ROCK), protein kinase B, and casein kinase 2. Our goal was to pinpoint the changes in protein kinase activity profile during decidualization in vitro and in vivo, and to establish how these changes are translated to the overall cellular phenotype and tissue morphology.