Regulation of Bcl-xL:: a little bit of this and a little bit of STAT

The Bcl-2 family of proteins are key regulators of apoptosis. Bcl-x(L) is an anti-apoptotic protein with a high degree of homology to Bcl-2; however, the signals that regulate Bcl-x(L) and Bcl-2 appear to be different. Levels of Bcl-x(L), but not Bcl-2, are increased in response to various survival signals. Furthermore, an inverse correlation between the levels of Bcl-2 and Bcl-x(L) has been reported for a number of cancers. Although the precise molecules that control Bcl-x(L) activity are unclear, the STAT, Rel/NF-kappaB, and Ets transcription factor families have recently been reported to directly regulate the bcl-x gene. Activated Ras, integrin, vitronectin, and hepatocyte growth factor signaling cascades have also been linked to changes in Bcl-x(L) expression. Bcl-x(L) can also be affected by post-translational mechanisms. Here we review recent advances in identifying the signaling pathways and factors involved in regulation of the bcl-x gene. Curr Opin Oncol 2000, 12:543-549 (C) 2000 Lippincott Williams & Wilkins, Inc.