Flip-Flop of Phospholipids in Vesicles: Kinetic Analysis with Time-Resolved Small-Angle Neutron Scattering

Nakano, Minoru; Fukuda, Masahiro; Kudo, Takayuki; Matsuzaki, Naoya; Azuma, Takuto; Sekine, Kazuhisa; Endo, Hitoshi; Handa, Tetsurou

doi:10.1021/jp900913w

Cited by 137 publications

(133 citation statements)

References 32 publications

Supporting

Mentioning

120

Contrasting

Order By: Relevance

“…Cholesterol has been reported to reduce the flip-flop rate of phospholipids [25,27]. The presence of cholesterol increases the acyl chain packing order and thereby inhibits solute permeation [28].…”

Section: Discussionmentioning

confidence: 99%

pH-dependent promotion of phospholipid flip-flop by the KcsA potassium channel

Nakao

Ikeda

Iwamoto

et al. 2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

Self Cite

View full text Add to dashboard Cite

KcsA is a pH-dependent potassium channel that is activated at acidic pH. The channel undergoes global conformational changes upon activation. We hypothesized that the open-close conformational changes of the transmem brane region could promote the flip-flop of phosphoiipids. Based on this hypothesis, we measured the flip-flop ofNBD-labeled phospholipids in KcsA-incorporated proteoliposomes. Both flip and flop rates of ~NBD-PC were significantly enhanced in the presence of KcsA and were several times higher at pH 4.0 than at pH 7.4, suggesting that KcsA promotes the phospholipid flip in a conformation-dependent manner. Phospholipids were nonselectively flipped with respect to the glycerophospholipid structure. In the active state of KcsA channel,tetrabutylammonium locks the channel in the open conformation at acidic pH; however, it did not alter the fliprate of CGNBD-PC. Thus, the open-close transition of the transmembrane region did not affect the flip-flop of phospholipids. In addition, the KcsA mutant that lacked anN-terminal amphipathic helix (MO-helix) was found to show reduced ability to fl ip C6NBD-phospholipids at acidic pH. The closed conformation is stabilized in the absence of MO-heli x, and thus the attenuated flip could be explained by the reduced prevalence of the open conformation.These results suggest that the open conformation of KcsA can disturb the bilayer integrity and facilitate the flip-flop of phospholipids.

show abstract

Section: Discussionmentioning

confidence: 99%

pH-dependent promotion of phospholipid flip-flop by the KcsA potassium channel

Nakao

Ikeda

Iwamoto

et al. 2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

Self Cite

View full text Add to dashboard Cite

show abstract

“…Preparation of Liposomes-Liposomes (large unilamellar vesicles) made of an acyl donor and acceptor mixture (PC/MLCL, PC/dilyso-CL (DLCL), or LPC/DLCL at a 9:1 molar ratio) were prepared by the extrusion method (46,47). Stock solutions of an acyl donor and acceptor in a methanol/chloroform (1:3, v/v) solution were mixed in the required proportion.…”

Section: Methodsmentioning

confidence: 99%

“…9A, taking PC(18:1-18:1)/sn-2Ј-MLCL(18:1-18:1/18:1-OH) liposomes (9:1 molar ratio) as an example. The concentrations of PCs in liposomal preparations were determined using an enzyme assay kit for choline (Wako, Osaka, Japan) (47).…”

Section: Methodsmentioning

confidence: 99%

Mechanism for Remodeling of the Acyl Chain Composition of Cardiolipin Catalyzed by Saccharomyces cerevisiae Tafazzin

Abe

Hasegawa

Oku

et al. 2016

Journal of Biological Chemistry

View full text Add to dashboard Cite

Remodeling of the acyl chains of cardiolipin (CL) is responsible for final molecular composition of mature CL after de novo CL synthesis in mitochondria. Yeast Saccharomyces cerevisiae undergoes tafazzin-mediated CL remodeling, in which tafazzin serves as a transacylase from phospholipids to monolyso-CL (MLCL). In light of the diversity of the acyl compositions of mature CL between different organisms, the mechanism underlying tafazzin-mediated transacylation remains to be elucidated. We investigated the mechanism responsible for transacylation using purified S. cerevisiae tafazzin with liposomes composed of various sets of acyl donors and acceptors. The results revealed that tafazzin efficiently catalyzes transacylation in liposomal membranes with highly ordered lipid bilayer structure. Tafazzin elicited unique acyl chain specificity against phosphatidylcholine (PC) as follows: linoleoyl (18:2) > oleoyl (18:1) ‫؍‬ palmitoleoyl (16:1) > > palmitoyl (16:0). In these reactions, tafazzin selectively removed the sn-2 acyl chain of PC and transferred it into the sn-1 and sn-2 positions of MLCL isomers at equivalent rates. We demonstrated for the first time that MLCL and dilyso-CL have inherent abilities to function as an acyl donor to monolyso-PC and acyl acceptor from PC, respectively. Furthermore, a Barth syndrome-associated tafazzin mutant (H77Q) was shown to completely lack the catalytic activity in our assay. It is difficult to reconcile the present results with the so-called thermodynamic remodeling hypothesis, which premises that tafazzin reacylates MLCL by unsaturated acyl chains only in disordered non-bilayer lipid domain. The acyl specificity of tafazzin may be one of the factors that determine the acyl composition of mature CL in S. cerevisiae mitochondria.

show abstract

“…79 Once established, it takes days to disrupt the asymmetrical distribution of phospholipids because spontaneous translocation across the bilayer is extremely low. 80,81 In this regard, a scramblase(s) is essential for quick PtdSer exposure during apoptosis. Figure 4 Structure of Xkr8, and its caspase-cleavage site.…”

mentioning

confidence: 99%