TP53INP2 is the new guest at the table of self-eating.

Summary

We identified a TP53INP1-related gene, which was named TP53INP2, using a bioinformatic approach. TP53INP1 and TP53INP2 sequences were found in higher eukaryotes but not in lower eukaryotes nor in prokaryotes. To gain insight into the function of the TP53INP2 protein, we carried out a number of protein-protein interaction approaches which showed that TP53INP2 binds to the Atg8-like proteins, as well as with the autophagosome transmembrane protein VMP1. TP53INP2 translocates from the nucleus to autophagosomes after activation of autophagy. We also showed that TP53INP2 expression is necessary for autophagosome development since its siRNA-mediated knockdown strongly decreases sensitivity to induced-autophagy. We suggest that TP53INP2 is a scaffold protein that recruits Atg8-like proteins to the autophagosome membrane by interacting with the transmembrane protein VMP1.