Bcl-2 and Bcl-x: regulatory switches for lymphoid death and survival.

The survival and death of lymphoid cells is under the control of a genetic program. Cell death is activated at different stages of development and serves to remove unnecessary and autoreactive lymphocytes, as well as to limit the immune response. The survival of cells is regulated by a set of genes that act as repressors of the cell death mechanism. Of these, bcl-2 and bcl-x exhibit a striking pattern of regulation during lymphoid maturation and can inhibit several forms of apoptotic cell death. Here, Gabriel Núñez and colleagues review recent developments in the field, particularly focusing on the role of the Bcl-2 and Bcl-x proteins in regulating lymphoid death and survival.