Phospho-YAP (Ser127) antibodies are essential tools for studying the Hippo signaling pathway, a critical regulator of organ size, tissue homeostasis, and cancer development. Yes-associated protein (YAP) is a transcriptional coactivator that promotes cell proliferation and survival. Its activity is tightly controlled by phosphorylation. When the Hippo pathway is active, the kinases LATS1/2 phosphorylate YAP at Ser127. leading to its cytoplasmic retention via binding to 14-3-3 proteins. This prevents YAP from entering the nucleus and activating target genes like *CTGF* and *CYR61*.
Phosphorylation at Ser127 is a key regulatory mechanism for YAP inactivation under conditions of cell-cell contact, stress, or differentiation. Antibodies specific to phospho-YAP (Ser127) allow researchers to detect this inactive form, providing insights into Hippo pathway activity in cellular and tissue samples. These antibodies are widely used in Western blotting, immunofluorescence, and immunohistochemistry to study YAP regulation in development, regeneration, and diseases such as cancer, where YAP dysregulation is common.
It’s important to distinguish phospho-YAP (Ser127) from other phosphorylation sites (e.g., Ser381) that mediate proteasomal degradation. The Ser127 phosphorylation event reflects acute signaling changes, making it a dynamic marker for pathway activation. Validating antibody specificity with phosphorylation-deficient mutants or phosphatase treatment is crucial for accurate interpretation. Overall, phospho-YAP (Ser127) antibodies are indispensable for probing Hippo-YAP signaling in both physiological and pathological contexts.