Apoptosis-induced translocation of nesprin-2 from the nuclear envelope to mitochondria is associated with mitochondrial dysfunction.

Accumulating evidence suggests that the nuclear envelope (NE) is not just a target, but also a mediator of apoptosis. We showed recently that the NE protein nesprin-2 has pro-apoptotic activity, which involves its subcellular redistribution and Bcl-2 proteins. Here we further characterize the pro-apoptotic activity of nesprin-2 focusing on its redistribution.

mTOR Inhibition Prolongs Survival and Has Beneficial Effects on Heart Function After Onset of Lamin A/C Gene Mutation Cardiomyopathy in Mice.

Background: Mutations in encoding nuclear envelope proteins lamin A/C cause dilated cardiomyopathy. Activation of the AKT/mTOR (RAC-α serine/threonine-protein kinase/mammalian target of rapamycin) pathway is implicated as a potential pathophysiologic mechanism. The aim of this study was to assess whether pharmacological inhibition of mTOR signaling has beneficial effects on heart function and prolongs survival in a mouse model of the disease, after onset of heart failure.

LINC complex protein nesprin-2 has pro-apoptotic activity via Bcl-2 family proteins.

The apoptotic intrinsic pathway is initiated by perforation of the mitochondrial outer membrane by the effector pro-apoptotic proteins of the Bcl-2 family, Bax and Bak. Bax and Bak need to be activated, a process facilitated by the action of BH3-only pro-apoptotic members of the Bcl-2 family. The latter either directly activates the effector proteins or antagonizes the action of pro-survival Bcl-2 family members such as Bcl-x.

Dynamic regulation of hepatic lipid metabolism by torsinA and its activators.

Depletion of torsinA from hepatocytes leads to reduced liver triglyceride secretion and marked hepatic steatosis. TorsinA is an atypical ATPase that lacks intrinsic activity unless it is bound to its activator, lamina-associated polypeptide 1 (LAP1) or luminal domain-like LAP1 (LULL1). We previously demonstrated that depletion of LAP1 from hepatocytes has more modest effects on liver triglyceride secretion and steatosis development than depletion of torsinA.

Long live lamins.

Mutations in genes encoding nuclear lamins cause diseases called laminopathies. In this issue, Hasper et al. (https://doi.