iProXProteomicsZilu YeHomo Sapienshttp://www.iprox.org/page/project.html?id=IPX0015016000yzl@ism.pumc.edu.cnState Key Laboratory of Common Mechanism Research for Major Diseases, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences & Peking Union Medical CollegeiProXfalseA Phosphoproteomic Landscape of Mammalian Preimplantation Development and Human Embryo ArrestProtein phosphorylation coordinates signal flow and cell-state transitions, but its global dynamics during mammalian preimplantation development have remained largely unresolved. Here we establish a cross-species phosphoproteomic atlas of early embryos using ultrasensitive workflows, quantifying ~6,000 phosphorylation sites in mouse and ~1,500 in human. Fertilization initiates a rapid, phosphatase-dominated reset of the maternal phosphoproteome, followed by a stepwise reconstruction of phosphorylation programs that culminates around the morula-to-blastocyst transition. Although individual phosphosites show limited conservation between species, pathway-level regulation is preserved, with marked species-biased timing across developmental stages. In mouse embryos, broad dephosphorylation of maternal proteins accompanies pronuclear formation, whereas phosphorylation of translation machinery rises in parallel with translational activation at the blastocyst stage. Functional perturbations further demonstrate that coordinated kinase activity is essential for successful blastocyst formation. Extending these measurements to the clinical setting, single-embryo phosphoproteomics of 52 human 8-cell-arrested embryos reveals arrest-specific, largely unannotated phosphosites and a rewired kinase-signaling architecture, offering mechanistic insight into preimplantation failure. Together, these data provide a reference framework for phosphorylation dynamics in early development and highlight candidate signaling nodes for diagnosis and targeted intervention in human infertility.Wed Jan 07 00:00:00 GMT 2026PXD0727269606