Palmitoylation of TEAD Transcription Factors Is Required for Their Stability and Function in Hippo Pathway Signaling

Abstract

The Hippo signaling pathway is responsible for regulating the function of TEAD family transcription factors in metazoans. TEADs, with their co-activators YAP/TAZ, are critical for controlling cell differentiation and organ size through their transcriptional activation of genes involved in cell growth and proliferation. Dysregulation of the Hippo pathway has been implicated in multiple forms of cancer. Here, we identify a novel form of regulation of TEAD family proteins. We show that human TEADs are palmitoylated at a universally conserved cysteine, and report the crystal structures of the human TEAD2 and TEAD3 YAP-binding domains in their palmitoylated forms. These structures show a palmitate bound within a highly conserved hydrophobic cavity at each protein's core. Our findings also demonstrate that this modification is required for proper TEAD folding and stability, indicating a potential new avenue for pharmacologically regulating the Hippo pathway through the modulation of TEAD palmitoylation.

Regulation of the Hippo Pathway Transcription Factor TEAD

“…Though the activity of TEAD is traditionally thought to be regulated through coactivator binding, with the majority of studies placing an emphasis on YAP/TAZ, several studies demonstrate Hippo independent mechanisms of TEAD regulation. Post-translational modifications such as phosphorylation and palmitoylation have been shown to effect TEAD DNA binding ability, protein stability, and coactivator interaction [52, 53, 78]. In addition, changes in TEAD subcellular localization represent an important mechanism to modulate TEAD transcriptional activity in a Hippo-independent manner [55, 56].…”

“…Recent studies have identified S-palmitoylation as a post-translational modification of the TEAD family and that the palmitoylation of TEADs regulates protein stability [52] and transcriptional activity [53]. Interestingly, TEAD palmitoylation is autocatalytic as the abundance of palmitoylation increased significantly with the addition of palmitoyl-CoA to purified TEAD in vitro, despite the absence of palmitoyltransferases [53].…”

“…Interestingly, despite loss of YAP binding, the TEAD1 palmitoylation mutants retained VGLL4 binding ability [53]. Disruption of TEAD2 palmitoylation decreased protein stability and resulted in a significant loss of TEAD2 protein abundance [52]. Palmitoylation is important for protein trafficking and membrane localization [54], however, palmitoylation of TEAD does not affect TEAD localization or membrane binding [52, 53].…”

“…Disruption of TEAD2 palmitoylation decreased protein stability and resulted in a significant loss of TEAD2 protein abundance [52]. Palmitoylation is important for protein trafficking and membrane localization [54], however, palmitoylation of TEAD does not affect TEAD localization or membrane binding [52, 53]. Consistently, the palmitoyl group is buried inside a deep hydrophobic pocket of TEAD as revealed by structure studies.…”

“…Flufenmate drugs were found to bind in this hydrophobic pocket and inhibit TEAD transcriptional activity, without disrupting YAP-TEAD interaction, leading to decreases in cell migration and proliferation [76]. Palmitoylation of TEAD occurs in this hydrophobic pocket suggesting that flufenmate drugs, despite a low binding affinity, may inhibit TEAD activity by displacing TEAD palmitoylation [52, 53]. In YAP/TAZ driven cancers, studies have explored the effects of disrupting YAP/TAZ-TEAD interaction.…”