Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Mol Biol Cell 2015 Jan 15;262:339-49.
Show Gene links Show Anatomy links

Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes.

Gillies LA , Du H , Peters B , Knudson CM , Newmeyer DD , Kuwana T .

Bax induces mitochondrial outer membrane permeabilization (MOMP), a critical step in apoptosis in which proteins are released into the cytoplasm. To resolve aspects of the mechanism, we used cryo-electron microscopy (cryo-EM) to visualize Bax-induced pores in purified mitochondrial outer membranes (MOMs). We observed solitary pores that exhibited negative curvature at their edges. Over time, the pores grew to ∼ 100-160 nm in diameter after 60-90 min, with some pores measuring more than 300 nm. We confirmed these results using flow cytometry, which we used to monitor the release of fluorescent dextrans from isolated MOM vesicles. The dextran molecules were released gradually, in a manner constrained by pore size. However, the release rates were consistent over a range of dextran sizes (10-500 kDa). We concluded that the pores were not static but widened dramatically to release molecules of different sizes. Taken together, the data from cryo-EM and flow cytometry argue that Bax promotes MOMP by inducing the formation of large, growing pores through a mechanism involving membrane-curvature stress.

PubMed ID: 25411335
PMC ID: PMC4294680
Article link:

Species referenced: Xenopus
Genes referenced: bak1 bax bid

Article Images: [+] show captions
References [+] :
Baker, Adding the third dimension to virus life cycles: three-dimensional reconstruction of icosahedral viruses from cryo-electron micrographs. 1999, Pubmed