Cytoskeletal Regulator Zyxin Stimulates Nuclear Translocation of YAP in Xenopus laevis Embryonic Cells

Objective: This study investigates the impact of zyxin on Yes-associated protein (YAP) signaling during embryonic development of the African clawed frog, Xenopus laevis. Zyxin, a mechanosensitive cytoskeletal protein, modulates cellular responses to mechanical tension and plays a pivotal role in actin dynamics regulation. Its ability to translocate to the nucleus in response to altered mechanical environments makes it critical for controlling gene expression essential for cellular morphogenesis and tissue architecture. Understanding zyxinʼs interactions with signaling pathways, particularly YAP signaling, is crucial given its implications in various pathological conditions, including cancer. Methods: To investigate zyxinʼs regulatory role in YAP signaling, we employed morpholino oligonucleotide microinjection to generate embryonic models with reduced zyxin expression and synthetic mRNA injection to achieve zyxin overexpression. Western blot analysis was performed to measure total YAP and phosphorylated YAP (pYAP) levels in embryos at various developmental stages. Immunohistochemical analysis was used to assess YAP subcellular distribution, specifically the nuclear-to-cytoplasmic ratio. Luciferase reporter assays quantified YAP transcriptional activity in response to altered zyxin expression levels. Results and Discussion: Total YAP levels remained constant across developmental stages in control embryos, despite increased phosphorylated YAP levels, indicating reduced pathway activity. Zyxin knockdown resulted in decreased YAP levels at early developmental stages, while zyxin overexpression enhanced nuclear localization of YAP, suggesting that zyxin promotes YAP nuclear translocation. Luciferase assays demonstrated increased YAP transcriptional activity in zyxin-overexpressing embryos, supporting the hypothesis that zyxin enhances YAP signaling through mechanical tension modulation. Conclusions: These results demonstrate zyxinʼs significant role in modulating YAP signaling pathways during embryonic development. The zyxin-YAP interaction is critical for proper cell signaling and morphogenesis, revealing potential therapeutic targets for diseases associated with dysregulated cell proliferation, including cancer. Future investigations will elucidate the mechanistic basis of zyxinʼs interactions with other YAP signaling pathway components and its influence on cellular dynamics and development, advancing our understanding of cellular mechanobiology with implications for regenerative medicine and therapeutic interventions.