title: Tubulin-blocked state of VDAC studied by polymer and ATP partitioning.
abstract: Recently reported functional interaction between voltage-dependent anion channel of the outer mitochondrial membrane, VDAC, and dimeric tubulin is observed as a reversible channel blockage. Using partitioning of poly-(ethylene glycol)s of different molecular weights and reversal potential measurements, we probe the size and ion selectivity of the fully open and tubulin-blocked states of VDAC reconstituted into planar lipid bilayers. While the effective radius of the channel decreases by only a factor of 1.34±0.15, the selectivity reverses from initially anionic to cationic. Directly measuring ATP partitioning we demonstrate that these changes prohibit ATP from entering the channel in its tubulin-blocked state.
authors: Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Philip A
authors: PA
authors: Gurnev
authors: Tatiana K
authors: TK
authors: Rostovtseva
authors: Sergey M
authors: SM
authors: Bezrukov
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism*; D015640:Ion Channel Gating / Q000502:physiology*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000737:chemistry / Q000378:metabolism; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism*; D050994:Voltage-Dependent Anion Channels / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008051:Lipid Bilayers; D011108:Polymers; D014404:Tubulin; D050994:Voltage-Dependent Anion Channels; D000255:Adenosine Triphosphate