ABCMdb

ABCB1 p.Ala266Phe

Predicted by SNAP2:	C: D (66%), D: D (85%), E: D (85%), F: D (85%), G: D (71%), H: D (80%), I: D (80%), K: D (85%), L: D (75%), M: D (53%), N: D (80%), P: D (91%), Q: D (80%), R: D (85%), S: N (66%), T: D (63%), V: D (80%), W: D (91%), Y: D (85%),
Predicted by PROVEAN:	C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D,

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Publications
[hide] Human P-glycoprotein contains a greasy ball-and-so... J Biol Chem. 2013 Jul 12;288(28):20326-33. doi: 10.1074/jbc.M113.484550. Epub 2013 Jun 3. Loo TW, Bartlett MC, Clarke DM
Human P-glycoprotein contains a greasy ball-and-socket joint at the second transmission interface.
J Biol Chem. 2013 Jul 12;288(28):20326-33. doi: 10.1074/jbc.M113.484550. Epub 2013 Jun 3., [PMID:23733192]

Abstract [show]
The P-glycoprotein drug pump protects us from toxins. Drug-binding sites in the transmembrane (TM) domains (TMDs) are connected to the nucleotide-binding domains (NBDs) by intracellular helices (IHs). TMD-NBD cross-talk is a key step in the transport mechanism because drug binding stimulates ATP hydrolysis followed by drug efflux. Here, we tested whether the IHs are critical for maturation and TMD-NBD coupling by characterizing the effects of mutations to the IH1 and IH2 interfaces. Although IH1 mutations had little effect, most mutations at the IH2-NBD2 interface inhibited maturation or activity. For example, the F1086A mutation at the IH2-NBD2 interface abolished drug-stimulated ATPase activity. The mutant F1086A, however, retained the ability to bind ATP and drug substrates. The mutant was defective in mediating ATP-dependent conformational changes in the TMDs because binding of ATP no longer promoted cross-linking between cysteines located at the extracellular ends of TM segments 6 and 12. Replacement of Phe-1086 (in NBD2) with hydrophobic but not charged residues yielded active mutants. The activity of the F1086A mutant could be restored when the nearby residue Ala-266 (in IH2) was replaced with aromatic residues. These results suggest that Ala-266/Phe-1086 lies in a hydrophobic IH2-NBD2 "ball-and-socket" joint.

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Sentences [show]
No. Sentence Comment
83 The double cysteine T333C/ L975C constructs (with or without the F1086A or A266F mutations) were transiently expressed in HEK 293 cells. Login to comment
110 The Ala-266/Phe-1086 contact point appeared to be critical for function because mutant A266C/F1086C was inactive (21). Login to comment