|
Description |
Detection of ATPase
activity of the MDR1 protein is a measure of transporter activity.
The assay is performed using purified membrane vesicles from Sf9 (Spodoptera
frugiperda) cells, expressing high levels of MDR1 protein. The ABC
transporters pump substrates out of the cell by using hydrolysis of
ATP as an energy source. ATP hydrolysis yields inorganic phosphate
(Pi), which can be detected by a simple colorimetric reaction. The
amount of Pi liberated is proportional to the activity of the
transporter. |
|
Diagnostic
Implications |
The MDR1 protein is
involved in cancer drug resistance and in the transport of
hydrophobic drugs and xenobiotics in the bowel, kidney, liver, and
the blood-brain barrier. In rodents, there are two MDR1 genes, mdr1a
and mdr1b, while in human, there is a single MDR1 gene. Based on
function and tissue distribution in rodents, the equivalent of the
human MDR1 gene product (PgP) is the product of the rodent mdr1b
gene. There have been no reported significant differences in
function, substrate specificity, or substrate affinity between these
two proteins. |