PH domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) (PHLPP2)

PH domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) is a serine/threonine phosphatase that acts as a key regulator of the PI3K/Akt and MYC signaling pathways (UniProt Q6ZVD8). Historically characterized as a tumor suppressor, PHLPP2 dephosphorylates Akt at its hydrophobic motif (Ser473), thereby inhibiting pro-survival signaling and promoting apoptosis (GeneCards). However, recent research has identified a paradoxical oncogenic role for PHLPP2 in metastatic prostate cancer, where it dephosphorylates and stabilizes the MYC oncogene, protecting it from degradation and driving disease progression (Nowak et al., 2019). This dual functionality makes PHLPP2 a complex therapeutic target, with small-molecule inhibitors such as NSC45586 and NSC117079 being investigated for their ability to suppress MYC-driven tumors (Sierecki et al., 2010). Additionally, PHLPP2 mRNA is a target for post-transcriptional regulation by various microRNAs and is being explored in the context of RNA-interference therapies (Frontiers in Oncology, 2023). The target is also implicated in metabolic diseases such as diabetes and non-alcoholic fatty liver disease due to its role in insulin signaling (NIH). Despite its promise, recent structural studies have challenged the intrinsic catalytic activity of PHLPP2, suggesting it may function primarily as a scaffold (PNAS, 2024). This scientific controversy poses a significant challenge for the development of activity-based inhibitors and necessitates careful validation in drug discovery programs.

Other names

PHLPPLPPM3BPH domain-containing family E member 1-likePleckstrin homology domain and leucine-rich repeat protein phosphatase 2

Small-molecule inhibition of the PHLPP2 phosphatase domain to reduce MYC stability and induce apoptosis in cancer cells; experimental knockdown of PHLPP2 mRNA using siRNA or antisense oligonucleotides to modulate Akt and MYC signaling.