Involved in the regulation of the TOR signaling pathway. Seems to act as a regulator of PP2A catalytic activity. RNAi plants show severe growth retardation, the formation of spontaneous disease-like nectrotic lesions leading to premature cell death. The defective plants also display a strong reduction in protein synthesis, and chromatin bridge formation at anaphase. Belongs to the IGBP1/TAP42 family.