Protein SET (I2PP2A)

Protein SET, also known as Inhibitor 2 of Protein Phosphatase 2A (I2PP2A), is a multifunctional protein that plays a critical role in cellular signaling, gene regulation, and oncogenesis [1, 2]. It was originally identified as part of the SET-CAN fusion gene in acute undifferentiated leukemia and has since been recognized as a potent endogenous inhibitor of Protein Phosphatase 2A (PP2A), a major tumor suppressor [1, 3]. By binding to the catalytic subunit of PP2A, SET prevents the dephosphorylation of key oncogenic signaling molecules such as AKT, ERK, and c-MYC, thereby promoting cell survival, proliferation, and transformation [1, 6]. Beyond its role as a phosphatase inhibitor, SET functions as a histone chaperone and a component of the Inhibitor of Acetyltransferases (INHAT) complex, where it regulates chromatin remodeling and gene transcription by masking histone acetylation sites [1, 5]. In clinical contexts, SET is frequently overexpressed in various malignancies, including leukemias and solid tumors like prostate and lung cancer, where its high levels correlate with poor prognosis and drug resistance [1, 4, 5]. It is also implicated in neurodegenerative diseases, particularly Alzheimer's disease, where its translocation to the cytoplasm contributes to the hyperphosphorylation of tau protein [1, 9]. Therapeutic strategies targeting SET focus on disrupting its interaction with PP2A to restore the phosphatase's tumor-suppressive activity [3, 7]. Small molecules and peptides such as Fingolimod (FTY720) and OP449 have shown promise in preclinical models by sequestering SET and derepressing PP2A, offering a multi-pathway approach to cancer therapy [3, 8, 12].

Other names

SETInhibitor 2 of protein phosphatase 2ATAF-ITAF-IbetaPHAPIISET nuclear oncogene

Inhibition of the SET-PP2A interaction to restore Protein Phosphatase 2A (PP2A) activity