Under stress conditions, apoptogenic factors normally sequestered in the mitochondrial intermembrane space are released into the cytosol, caspases are activated and cells die by apoptosis. Although the precise mechanism that leads to the permeabilization of mitochondria is still unclear, the activation of multidomain pro-apoptotic proteins of the Bcl-2 family, such as Bax and Bak, is evidently ...

The net methylation of methyl-accepting chemotaxis proteins (MCPs) is the biochemical manifestation of physiological adaptation to amino acid chemoattractants by Escherichia coli (4). In Bacillus subtilis, demethylation of MCPs occurs during such adaptation (3). The activity of chemotaxis methyltransferase is detectable in vivo and in vitro. As an alternative assay, whole cells can be permeabil...

Melittin (MLT), the 26-residue toxic peptide from the European honeybee Apis mellifera, is widely used for studying the principles of membrane permeabilization by antimicrobial and other host-defense peptides. A striking property of MLT is that its ability to permeabilize zwitterionic phospholipid vesicles is dramatically reduced upon the addition of anionic lipids. Because the mechanism of per...

Obesity in both humans and rodents is characterized by adipocyte hypertrophy and the presence of death adipocytes surrounded by macrophages forming "crown-like structures." However, the biochemical pathways involved in triggering adipocyte death as well as the role of death adipocytes in adipose tissue remodeling and macrophage infiltration remain poorly understood. We now show that induction o...

RNA interference-mediated gene silencing offers the potential of targeted inhibition of disease-relevant genes. In vivo delivery of RNAi reagents can be obtained by a variety of approaches. Physical delivery methods appear safer and lack side effects. Electro-permeabilization is one of the non-viral methods successfully used to transfer small interfering RNAs (siRNAs) in vitro and in vivo. A pr...

Little is known about the temporal relationship between mitochondrial and plasma membrane potential changes and outer mitochondrial membrane permeabilization during apoptosis. Confocal imaging of breast carcinoma and HeLa cells stably transfected with cytochrome-C-GFP demonstrated that mitochondria rapidly depolarized after the release of the fusion protein into the cytosol. Of note, mitochondr...