Apoptotic Stress Induces Bax-dependent, Caspase-independent Redistribution of LINC Complex Nesprins
Overview
Authors
Affiliations
The canonical function of Bcl-2 family proteins is to regulate mitochondrial membrane integrity. In response to apoptotic signals the multi-domain pro-apoptotic proteins Bax and Bak are activated and perforate the mitochondrial outer membrane by a mechanism which is inhibited by their interaction with pro-survival members of the family. However, other studies have shown that Bax and Bak may have additional, non-canonical functions, which include stress-induced nuclear envelope rupture and discharge of nuclear proteins into the cytosol. We show here that the apoptotic stimuli cisplatin and staurosporine induce a Bax/Bak-dependent degradation and subcellular redistribution of nesprin-1 and nesprin-2 but not nesprin-3, of the linker of nucleoskeleton and cytoskeleton (LINC) complex. The degradation and redistribution were caspase-independent and did not occur in Bax/Bak double knockout (DKO) mouse embryo fibroblasts (MEFs). Re-expression of Bax in Bax/Bak DKO MEFs restored stress-induced redistribution of nesprin-2 by a mechanism which requires Bax membrane localization and integrity of the α helices 5/6, and the Bcl-2 homology 3 (BH3) domain. We found that nesprin-2 interacts with Bax in close proximity to perinuclear mitochondria in mouse and human cells. This interaction requires the mitochondrial targeting and N-terminal region but not the BH3 domain of Bax. Our results identify nesprin-2 as a Bax binding partner and also a new function of Bax in impairing the integrity of the LINC complex.
Birks S, Howard S, Wright C, ORourke C, Day E, Lamb A PLoS One. 2024; 19(11):e0307816.
PMID: 39565744 PMC: 11578491. DOI: 10.1371/journal.pone.0307816.
Zohar H, Lindenboim L, Gozlan O, Gundersen G, Worman H, Stein R Nucleus. 2024; 15(1):2413501.
PMID: 39402980 PMC: 11486236. DOI: 10.1080/19491034.2024.2413501.
Bai J, Sun W, Zheng W, Wang X, Bai Y Mol Cell Biochem. 2024; .
PMID: 39377871 DOI: 10.1007/s11010-024-05130-w.
Calpain-1 weakens the nuclear envelope and promotes the release of neutrophil extracellular traps.
Singh J, Zlatar L, Munoz-Becerra M, Lochnit G, Herrmann I, Pfister F Cell Commun Signal. 2024; 22(1):435.
PMID: 39252008 PMC: 11384698. DOI: 10.1186/s12964-024-01785-6.
The minimal membrane requirements for BAX-induced pore opening upon exposure to oxidative stress.
Mystek P, Singh V, Horvath M, Honzejkova K, Riegerova P, Evci H Biophys J. 2024; 123(20):3519-3532.
PMID: 39188056 PMC: 11494524. DOI: 10.1016/j.bpj.2024.08.017.