Homeodomain proteins and eukaryotic translation initiation factor 4E (eIF4E): an unexpected relationship.

The central role of post-transcriptional modification of the expression of several genes involved in tumorigenesis implicates eIF4E as a pivotal factor in the regulation of cell survival, growth and proliferation. Overexpression of eIF4E leads to malignant transformation in vitro and induces tumor formation in vivo. Furthermore, upregulated expression of eIF4E has been reported in a variety of human malignancies. Consequently, studies over the last ten years have sought to better characterize the molecular mechanisms and cellular factors that control eIF4E activity. These efforts have revealed a role for eIF4E in diverse biological processes including embryonic development, cell cycle progression, synaptic plasticity and cancer. In this review we focus on several members of the homeodomain protein family, which have recently been identified as a novel class of eIF4E regulators.