Focal adhesion kinase phosphorylates the phosphatase and tensin homolog deleted on chromosome 10 under the control of p110δ phosphoinositide‐3 kinase

Abstract

The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) tumor suppressor protein is regulated by various mechanisms that are not fully understood. This includes regulation by Tyr phosphorylation by a mechanism that remains elusive. Here, we show that focal adhesion kinase (FAK) phosphorylates PTEN in vitro, in cell-free systems and in cells. Furthermore, by mass spectrometry, we identified Tyr336 on PTEN as being phosphorylated by FAK. Tyr336 phosphorylation increased phosphatase activity, protein-lipid interaction, and protein stability of PTEN. In cells, including primary mouse macrophages and human cancer cell lines, FAK was found to be negatively regulated by p110d phosphoinositide-3 kinase (PI3K), whereas the activation of FAK was positively regulated by RhoA-associated kinase (ROCK). Indeed, the phosphorylation of FAK was unexpectedly increased in macrophages derived from mice expressing kinase-dead p110d. Pharmacologic inactivation of RhoA/ROCK reduced the phosphorylation of FAK to normal levels in cells with genetically inactivated p110d. Likewise, pharmacologic inactivation of FAK reduced the phosphorylation of PTEN in cells expressing kinase-dead p110d and restored the functional defects of p110d inactivation, including Akt phosphorylation and cell proliferation. This work identifies FAK as a target of p110d PI3K that links RhoA with PTEN and establishes for the first time that PTEN is a substrate of FAK-mediated Tyr phosphorylation.-Tzenaki, N., Aivaliotis, M., Papakonstanti, E. A. Focal adhesion kinase phosphorylates the phosphatase and tensin homolog deleted on chromosome 10 under the control of p110d phosphoinositide-3 kinase. FASEB J. 29, 4840-4852 (2015). www.fasebj.org

Endogenous Control Mechanisms of FAK and PYK2 and Their Relevance to Cancer Development

“…Both the p85 subunit of the PI3K and the SH2-SH3 fragment of Src kinase bind to the Y397-phosphorylated FERM-linker fragment [ 4 , 28 , 89 , 90 , 116 , 117 ], suggesting that PTEN binding involves the same region. Moreover, it has been observed that FAK phosphorylates PTEN at Y336 with a positive effect on PTEN stability and phosphatase activity [ 118 , 119 ]. Y336 is located in the phospholipid-binding region of the C2 domain ( Figure 3 ).…”

Germline TTN variants are enriched in PTEN-wildtype Bannayan–Riley–Ruvalcaba syndrome

“… 40 , 41 Interestingly, PTEN has also been shown to be phosphorylated by FAK at Tyr336, downstream of RhoA/ROCK, resulting in association of PTEN to the membrane, increased PTEN phosphatase activity, and protein stability. 42 In other contexts, FAK phosphorylation of PTEN causes PTEN to enter the nucleus (and hence, resulting in increased degradation). As PTEN protein stability is regulated through ubiquitination, and mono-ubiquitination of PTEN is crucial for nuclear import, 43 we predict that the cross-talk between FAK and PTEN could also regulate PTEN subcellular localization and overall stability.…”

Endogenous Control Mechanisms of FAK and PYK2 and Their Relevance to Cancer Development and Therapy

“…Both the p85 subunit of the PI3K and the SH2-SH3 fragment of Src kinase bind to the Y397-phosphorylated FERM-linker fragment [25,71,78,79,105,106], suggesting that PTEN binding involves the same region. Moreover, it has been observed that FAK phosphorylates PTEN at Y336 with a positive effect on PTEN stability and phosphatase activity [107,108]. Y336 is located in the phospholipid-binding region of the C2 domain (Figure 3).…”