TABLE 1

Protein expression levels of membrane proteins in isolated brain capillary fraction of WT, Mdr1a/1b-KO, and hMDR1-MAC mice

Brain capillary fractions were prepared from pooled frozen brains of WT, Mdr1a/1b-KO, and hMDR1-MAC mice (10 mice/group), and the protein expression levels were quantified by LC-MS/MS. The protein expression levels in four sets of transitions in one pooled sample from 10 mice were used to calculate the average (mean) and variability (S.E.M.), which are shown as the mean ± S.E.M. Peak area ratio was lower than the lowest point of the standard curve (0.5 fmol/5 μg of protein).

Molecular NamesProtein Expression Level
WT MiceMdr1a/1b-KO MicehMDR1-MAC Mice
(fmol/µg of protein)
Human MDR1 and Mouse Mdr1aa5.15 ± 0.62ULQ (<0.10)2.21 ± 0.19*
Human MDR1bULQ (<0.10)ULQ (<0.10)2.77 ± 0.05
Mouse Mdr1ac4.30 ± 0.21ULQ (<0.10)ULQ (<0.10)
Mouse Mdr1bULQ (<0.10)ULQ (<0.10)ULQ (<0.10)
Mrp40.54 ± 0.010.51 ± 0.020.89 ± 0.02*
Bcrp2.24 ± 0.092.61 ± 0.123.61 ± 0.15*
Na+, K+-ATPase66.75 ± 3.41153.18 ± 6.63*116.43 ± 3.09*
  • ULQ, under the limit of quantification.

  • a Measured by using a peptide probe set common for human MDR1 and mouse Mdr1a.

  • b Measured by using a peptide probe set specific for human MDR1.

  • c Measured by using a peptide probe set specific for mouse Mdr1a.

  • * P < 0.01, significantly different from the protein expression amounts in brain capillaries isolated from WT mice.