Drug-stimulated ATPase activity of a deletion mutant of the human multidrug-resistance protein (MDR1)

Details

Serval ID
serval:BIB_9C504EF8F563
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Drug-stimulated ATPase activity of a deletion mutant of the human multidrug-resistance protein (MDR1)
Journal
Biochemical and Biophysical Research Communications
Author(s)
Welker  E., Szabo  K., Hollo  Z., Muller  M., Sarkadi  B., Varadi  A.
ISSN
0006-291X (Print)
Publication state
Published
Issued date
11/1995
Volume
216
Number
2
Pages
602-9
Notes
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Nov 13
Abstract
The baculovirus-insect cell system has been used for the functional expression of the human multidrug resistance protein (MDR1) and a mutant MDR1 variant lacking a twenty amino acid segment from the first extracellular loop (delta aa78-97 MDR1). Both MDR1 proteins were found to be correctly inserted into the insect cell membrane as indicated by their interaction with MRK 16 antibody. The removal of the 78-97 segment from the first extracellular loop dramatically altered drug-stimulated ATPase activity. Rhodamine 123 or vinblastine were not able to stimulate the mutant protein and Calcein AM had also little effect. In contrast, verapamil increased the ATPase activity of the mutant almost to the same maximal level as that of the wild type. However, the verapamil concentration needed for the half maximal stimulation of the ATPase activity was found to be about hundred times higher than that for the wild type MDR1. These results indicate that a partial deletion of an extracellular loop modulates the affinity of MDR1 for its transportable substrates in a variable fashion.
Keywords
Adenosine Triphosphatases/isolation & purification/*metabolism Baculoviridae Cell Membrane/metabolism Flow Cytometry Genetic Vectors Humans Kinetics Mutagenesis P-Glycoprotein/isolation & purification/*metabolism Recombinant Proteins/isolation & purification/metabolism Sequence Deletion Transfection Variation (Genetics)
Pubmed
Web of science
Create date
24/01/2008 14:40
Last modification date
20/08/2019 15:03
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