Relevance of conserved lysine and arginine residues in transmembrane helices for the transport activity of organic anion transporting polypeptide 1B3.

ABSTRACT:

Background and purpose

Organic anion transporting polypeptide 1B3 (OATP1B3) (SLCO1B3) mediates the uptake of endogenous substrates (e.g. estrone-3-sulphate) and drugs (e.g. pravastatin) from blood into hepatocytes. Structure-based modelling of OATP1B3 suggested that a pore with a positive electrostatic potential contributes to the transport mechanism. Therefore, we investigated the role of conserved positively charged amino acids for OATP1B3-mediated uptake of sulphobromophthalein (BSP) and pravastatin.

Experimental approach

Residues Lys28, Lys41 and Arg580 in OATP1B3 were substituted by alanine, arginine, glutamine, glycine or lysine. Using immunofluorescence, immunoblot analysis and cellular uptake assays, the effect of these mutations on protein expression and transport a

SUBMITTER: Glaeser H 

PROVIDER: S-EPMC2828033 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature