Structural insights for selective disruption of Beclin 1 binding to Bcl-2
Yun-Zu Pan, Qiren Liang, Diana R. Tomchick, Jef K. De Brabander, Josep Rizo
Abstract
Stimulation of autophagy could provide powerful therapies for multiple diseases, including cancer and neurodegeneration. An attractive drug target for this purpose is Bcl-2, which inhibits autophagy by binding to the Beclin 1 BH3-domain. However, compounds that preclude Beclin 1/Bcl-2 binding might also induce apoptosis, which is inhibited by binding of Bcl-2 to BH3-domains of pro-apoptosis factors such as Bax. Here we describe the NMR structure of Bcl-2 bound to 35, a compound that we recently found to inhibit Beclin 1/Bcl-2 binding more potently than Bax/Bcl-2 binding. The structure shows that 35 binds at one end of the BH3-binding groove of Bcl-2. Interestingly, much of the 35-binding site is not involved in binding to Bcl-2 inhibitors described previously and mediates binding to Beclin 1 but not Bax. The structure suggests potential avenues to design compounds that disrupt Beclin 1/Bcl-2 binding and stimulate autophagy without inducing apoptosis.