The BTG/TOB family protein TIS21 regulates stage-specific proliferation of developing thymocytes.

As thymocytes undergo differentiation in the thymus, they progress through distinct phases of quiescence and proliferation. Identifying cellular mechanisms that maintain thymocytes in a non-dividing state is critical to fully understand T cell development. A member of the B cell translocation gene/transducer of ErbB-2 (BTG/TOB) family of anti-proliferative proteins was identified as a key mediator of the quiescent state in peripheral anergic and unstimulated T cells.