The bifunctional role of TP53INP2 in transcription and autophagy.

Cells integrate intracellular and extracellular cues to precisely control the balance of anabolic and catabolic processes, which is essential for cells to maintain homeostasis. The nuclear protein TP53INP2 (tumor protein p53 inducible nuclear protein 2) has emerged as one of the key players participating in both anabolic and catabolic processes. In the nucleus including the nucleolus, TP53INP2 binds to multiple transcription-related factors to modulate transcription, such as the transcription of thyroid hormone-related genes and ribosomal DNA. Interestingly, upon nutrient deprivation, TP53INP2 rapidly moves from the nucleus to the cytoplasm and participates in the regulation of macroautophagy/autophagy. By acting as a nutrient status sensor, TP53INP2 switches its role between transcription and autophagy by changing its subcellular localization and helps the cell to cope with environmental changes. ABBREVIATIONS: Atg: autophagy related; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MTORC1: mechanistic target of rapamycin kinase complex 1; rDNA: ribosomal DNA; TP53INP2: tumor protein p53 inducible nuclear protein 2; UIM: ubiquitin-interacting motif.