The American journal of pathology
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The Yes-associated protein (YAP), an oncoprotein in the Hippo tumor suppressor pathway, regulates tumorigenesis and has been found in a variety of tumors, including breast, ovarian, and hepatocellular cancers. Although YAP functions through its WW domains, the YAP WW domain-binding partners have not yet been completely determined. With this study, we demonstrate that YAP functions partially through its binding to KLF5, a transcription factor that promotes breast cell proliferation and survival. ⋯ The YAP upstream kinase LATS1 suppressed the KLF5-FGF-BP axis, as well as cell growth through YAP signaling. Both YAP and KLF5 are coexpressed in estrogen receptor ERα-negative breast cell lines. These findings suggest that KLF5 could be an important transcription factor partner for YAP and may contribute to the Hippo pathway.