Mcl-1 is a unique Bcl-2 family member that plays crucial roles in apoptosis. Apoptosis-unrelated functions of Mcl-1 are however emerging, further justifying its tight regulation. Here we unravel a novel mechanism of Mcl-1 regulation mediated by the haplo-insufficient tumour suppressor Beclin 1. Beclin 1 negatively modulates Mcl-1 stability in a reciprocal manner whereby depletion of one leads to the stabilization of the other. This co-regulation is independent of autophagy and of their physical interaction. Both Beclin 1 and Mcl-1 are deubiquitinated and thus stabilized by binding to a common deubiquitinase, USP9X. Beclin 1 and Mcl-1 negatively modulate the proteasomal degradation of each other through competitive displacement of USP9X. The analysis of patient-derived melanoma cells and tissue samples shows that the levels of Beclin 1 decrease, while Mcl-1 levels subsequently increase during melanoma progression in a significant inter-dependent manner. The identified inverse co-regulation of Beclin 1 and Mcl-1 represents a mechanism of functional counteraction in cancer.

Elgendy, M., Ciro, M., Abdel Aziz, A.k., Belmonte, G., Dal Zuffo, R., Mercurio, C., et al. (2014). Beclin 1 restrains tumorigenesis through Mcl-1 destabilization in an autophagy-independent reciprocal manner. NATURE COMMUNICATIONS, 5(Article number: 5637), 1-11 [10.1038/ncomms6637].

Beclin 1 restrains tumorigenesis through Mcl-1 destabilization in an autophagy-independent reciprocal manner.

BELMONTE, GIUSEPPE;MIRACCO, CLELIA;
2014-01-01

Abstract

Mcl-1 is a unique Bcl-2 family member that plays crucial roles in apoptosis. Apoptosis-unrelated functions of Mcl-1 are however emerging, further justifying its tight regulation. Here we unravel a novel mechanism of Mcl-1 regulation mediated by the haplo-insufficient tumour suppressor Beclin 1. Beclin 1 negatively modulates Mcl-1 stability in a reciprocal manner whereby depletion of one leads to the stabilization of the other. This co-regulation is independent of autophagy and of their physical interaction. Both Beclin 1 and Mcl-1 are deubiquitinated and thus stabilized by binding to a common deubiquitinase, USP9X. Beclin 1 and Mcl-1 negatively modulate the proteasomal degradation of each other through competitive displacement of USP9X. The analysis of patient-derived melanoma cells and tissue samples shows that the levels of Beclin 1 decrease, while Mcl-1 levels subsequently increase during melanoma progression in a significant inter-dependent manner. The identified inverse co-regulation of Beclin 1 and Mcl-1 represents a mechanism of functional counteraction in cancer.
2014
Elgendy, M., Ciro, M., Abdel Aziz, A.k., Belmonte, G., Dal Zuffo, R., Mercurio, C., et al. (2014). Beclin 1 restrains tumorigenesis through Mcl-1 destabilization in an autophagy-independent reciprocal manner. NATURE COMMUNICATIONS, 5(Article number: 5637), 1-11 [10.1038/ncomms6637].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/974283
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