Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
2003-12-9
pubmed:abstractText
It is known that the proapoptotic protein Bax facilitates the formation of pores in bilayers, resulting in the release of proteins from the intermitochondrial space. We demonstrate that another consequence of the interaction of Bax with membranes is an increase in the rate of lipid transbilayer diffusion. We use two independent assays for transbilayer diffusion, one involving the formation of asymmetric liposomes by placing a pyrene-labeled lipid into the outer monolayer of preformed vesicles and another assay based on the initial preparation of liposomes having an asymmetric transbilayer distribution of lipids. With both methods we find that oligomeric BaxDeltaC or full-length Bax in the presence of tBid, but not monomeric full-length Bax, strongly promotes the rate of transbilayer diffusion. Although biological membranes exhibit rates of lipid transbilayer diffusion of minutes or less, they are able to maintain an asymmetric distribution of lipids across the bilayer. In the case of mitochondria, cardiolipin is sequestered on the inner leaflet of the inner mitochondrial membrane. However, during apoptosis this lipid translocates to the outer surface of the outer mitochondrial membrane. This phenomenon must involve an increase in the rate of transbilayer diffusion. The results of the present paper demonstrate that an activated form of Bax can cause this increased rate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14576-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:14661970-Apoptosis, pubmed-meshheading:14661970-BH3 Interacting Domain Death Agonist Protein, pubmed-meshheading:14661970-Cardiolipins, pubmed-meshheading:14661970-Carrier Proteins, pubmed-meshheading:14661970-Diffusion, pubmed-meshheading:14661970-Humans, pubmed-meshheading:14661970-Intracellular Membranes, pubmed-meshheading:14661970-Lipid Bilayers, pubmed-meshheading:14661970-Liposomes, pubmed-meshheading:14661970-Mitochondria, pubmed-meshheading:14661970-Models, Chemical, pubmed-meshheading:14661970-Molecular Mimicry, pubmed-meshheading:14661970-Permeability, pubmed-meshheading:14661970-Protein Transport, pubmed-meshheading:14661970-Proto-Oncogene Proteins, pubmed-meshheading:14661970-Proto-Oncogene Proteins c-bcl-2, pubmed-meshheading:14661970-Scattering, Radiation, pubmed-meshheading:14661970-bcl-2-Associated X Protein
pubmed:year
2003
pubmed:articleTitle
Transbilayer lipid diffusion promoted by Bax: implications for apoptosis.
pubmed:affiliation
Department of Biochemistry, McMaster University Health Sciences Centre, Hamilton, Ontario L8N 3Z5, Canada. epand@mcmaster.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't