Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 281, Issue 25, Pages 17347-17358Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M600906200
Keywords
-
Categories
Funding
- NIDDK NIH HHS [DK51526] Funding Source: Medline
Ask authors/readers for more resources
Cell function depends on the distribution of cytosolic and mitochondrial factors across the outer mitochondrial membrane (OMM). Passage of metabolites through the OMM has been attributed to the voltage-dependent anion-selective channel (VDAC), which can form a large conductance and permanently open a channel in lipid bilayers. However, recent data indicate that the transport of metabolites through the OMM is controlled in the cells. Recognizing that the bilayer studies had been commonly conducted at supraphysiological [Ca2+] and [K+], we determined the effect of Ca2+ on VDAC activity. In liposomes, the purified VDAC displays Ca2+ -dependent control of the molecular cut-off size and shows Ca2+ -regulated Ca2+ permeability in the physiological [Ca2+] range. In bilayer experiments, at submicromolar [Ca2+], the purified VDAC or isolated OMM does not show sustained large conductance but rather exhibits gating between a nonconducting state and various subconductance states. Ca2+ addition causes a reversible increase in the conductance and may evoke channel opening to full conductance. Furthermore, single cell imaging data indicate that Ca2+ may facilitate the cation and ATP transport across the OMM. Thus, the VDAC gating is dependent on the physiological concentrations of cations, allowing the OMM to control the passage of ions and some small molecules. The OMM barrier is likely to decrease during the calcium signal.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available