Expanding roles for ThPOK in thymic development


Dietmar J. Kappes
Institute for Cancer Research
Fox Chase Cancer Center
333 Cottman Avenue
Philadelphia, PA 19111, USA
Tel.: +1 215 728 5374
Fax: +1 215 214 1584
e-mail: dietmar.kappes@fccc.edu


Summary:  The role of the zinc finger transcription factor ThPOK (T-helper-inducing POZ–Kruppel-like factor) in promoting commitment of αβ T cells to the CD4 lineage is now well established. New results indicate that ThPOK is also important for the development and/or acquisition of effector functions by other T cell subsets, including several not marked by CD4 expression, i.e. double-negative invariant natural killer T (iNKT) cells, γδ cells, and even memory CD8+ T cells. There is compelling evidence that ThPOK expression in most or all of these cases is dependent on T-cell receptor signaling and that differences in relative TCR signal strength/length may induce different levels of ThPOK expression. The developmental consequences of ThPOK expression vary according to cell type, which may partly reflect differences in ThPOK levels and/or in transcriptional networks between cell types.