4E-BP2 hardwires lymphocytes for rapamycin sensitivity.

The mTORC1 [mammalian (or mechanistic) target of rapamycin complex 1] inhibitor rapamycin is a potent inhibitor of T and B lymphocyte growth and proliferation. In this issue of Science Signaling, So et al found that the isoform of 4E-BP (4E-BP2) in lymphocytes that regulates messenger RNA translation is more sensitive to the effects of rapamycin than is the 4E-BP isoform found in nonlymphoid cells. Furthermore, inhibition of 4E-BP2 blocks both the growth and proliferation of lymphocytes.