Bergen Open Research Archive

HAMLET interacts with lipid membranes and perturbs their structure and integrity

Bergen Open Research Archive

Show simple item record Mossberg, Ann-Kristin eng Puchades, Maja eng Halskau, Øyvind eng Baumann, Anne eng Lanekoff, Ingela eng Chao, Yinxia eng Martinez, Aurora eng Svanborg, Catharina eng Karlsson, Roger eng 2010-12-13T09:50:15Z 2010-12-13T09:50:15Z 2010-01-23 eng
dc.identifier.citation PLoS ONE 5(2): e9384 en
dc.identifier.issn 1932-6203 eng
dc.description.abstract Background Cell membrane interactions rely on lipid bilayer constituents and molecules inserted within the membrane, including specific receptors. HAMLET (human α-lactalbumin made lethal to tumor cells) is a tumoricidal complex of partially unfolded α-lactalbumin (HLA) and oleic acid that is internalized by tumor cells, suggesting that interactions with the phospholipid bilayer and/or specific receptors may be essential for the tumoricidal effect. This study examined whether HAMLET interacts with artificial membranes and alters membrane structure. Methodology/Principal Findings We show by surface plasmon resonance that HAMLET binds with high affinity to surface adherent, unilamellar vesicles of lipids with varying acyl chain composition and net charge. Fluorescence imaging revealed that HAMLET accumulates in membranes of vesicles and perturbs their structure, resulting in increased membrane fluidity. Furthermore, HAMLET disrupted membrane integrity at neutral pH and physiological conditions, as shown by fluorophore leakage experiments. These effects did not occur with either native HLA or a constitutively unfolded Cys-Ala HLA mutant (rHLAall-Ala). HAMLET also bound to plasma membrane vesicles formed from intact tumor cells, with accumulation in certain membrane areas, but the complex was not internalized by these vesicles or by the synthetic membrane vesicles. Conclusions/Significance The results illustrate the difference in membrane affinity between the fatty acid bound and fatty acid free forms of partially unfolded HLA and suggest that HAMLET engages membranes by a mechanism requiring both the protein and the fatty acid. Furthermore, HAMLET binding alters the morphology of the membrane and compromises its integrity, suggesting that membrane perturbation could be an initial step in inducing cell death. en
dc.language.iso eng eng
dc.publisher Public Library of Science eng
dc.rights Attribution CC BY eng
dc.rights.uri eng
dc.title HAMLET interacts with lipid membranes and perturbs their structure and integrity eng
dc.type Peer reviewed eng
dc.type Journal article eng
dc.subject.nsi VDP::Medisinske Fag: 700::Basale medisinske, odontologiske og veterinærmedisinske fag: 710::Medisinsk biokjemi: 726 nob
dc.rights.holder Copyright 2010 Mossberg et al.
dc.rights.holder Mossberg et al. eng
dc.type.version publishedVersion eng
bora.peerreviewed Peer reviewed eng
bora.cristinID 340800 eng
bibo.doi eng
dc.identifier.cristinID 340800 eng

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