The yeast eIF4E-associated protein Eap1p attenuates GCN4 translation upon TOR-inactivation.

Amino acid-starved yeast activates the eIF2alpha kinase Gcn2p to suppress general translation and to selectively derepress the transcription factor Gcn4p, which induces various biosynthetic genes to elicit general amino acid control (GAAC). Well-fed yeast activates the target of rapamycin (TOR) to stimulate translation via the eIF4F complex. A crosstalk was demonstrated between the pathways for GAAC and TOR signaling: the TOR-specific inhibitor rapamycin activates Gcn2p. Here we demonstrate that, upon TOR-inactivation, the putative TOR-regulated eIF4E-associated protein Eap1p likely functions downstream of Gcn2p to attenuate GCN4 translation via a mechanism independent of eIF4E-binding, thereby constituting another interface between the two pathways.