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@ARTICLE{Wittern:273914,
author = {Wittern, Carla Isabel and Schröder, Sophie and Jensen, Ole
and Brockmöller, Jürgen and Gebauer, Lukas},
title = {{C}omprehensive characterization of the {OCT}1
phenylalanine-244-alanine substitution reveals highly
substrate-dependent effects on transporter function.},
journal = {The journal of biological chemistry},
volume = {300},
number = {11},
issn = {0021-9258},
address = {Bethesda, Md.},
publisher = {Soc.},
reportid = {DZNE-2024-01388},
pages = {107835},
year = {2024},
note = {ISSN 0021-9258 not unique: **2 hits**.},
abstract = {Organic cation transporters (OCTs) can transport
structurally highly diverse substrates. The molecular basis
of this extensive polyspecificity has been further
elucidated by cryo-EM. Apparently, in addition to negatively
charged amino acids, aromatic residues may contribute to
substrate binding and substrate selectivity. In this study,
we provide a comprehensive characterization of phenylalanine
244 in OCT1 function. We analyzed the uptake of 144 OCT1
substrates for the phenylalanine 244 to alanine substitution
compared to WTOCT1. This substitution had highly
substrate-specific effects ranging from transport reduced to
$10\%$ of WT activity up to 8-fold increased transport
rates. Four percent of substrates showed strongly increased
uptake $(>200\%$ of WT) whereas $39\%$ showed strongly
reduced transport $(<50\%$ of WT). Particularly with larger,
more hydrophobic, and more aromatic substrates, the
Phe244Ala substitution resulted in higher transport rates
and lower inhibition of the transporter. In contrast,
substrates with a lower molecular weight and less aromatic
rings showed generally decreased uptake rates. A comparison
of our data to available transport kinetic data demonstrates
that generally, high-affinity low-capacity substrates show
increased uptake by the Phe244Ala substitution, whereas
low-affinity high-capacity substrates are characterized by
reduced transport rates. Altogether, our study provides the
first comprehensive characterization of the functional role
of an aromatic amino acid within the substrate translocation
pathway of OCT1. The pleiotropic function further highlights
that phenylalanine 244 interacts in a highly specific manner
with OCT1 substrates and inhibitors.},
keywords = {Humans / Phenylalanine: metabolism / Phenylalanine:
chemistry / Amino Acid Substitution / Substrate Specificity
/ HEK293 Cells / Alanine: metabolism / Alanine: chemistry /
Kinetics / Biological Transport / Organic Cation Transporter
1: metabolism / Organic Cation Transporter 1: genetics /
Organic Cation Transporter 1: chemistry / alanine
mutagenesis (Other) / binding pocket (Other) / inhibition
(Other) / organic cation transporter 1 (Other) /
polyspecificity (Other) / site-directed mutagenesis (Other)
/ transport (Other) / Phenylalanine (NLM Chemicals) /
Alanine (NLM Chemicals) / Organic Cation Transporter 1 (NLM
Chemicals)},
cin = {Clinical Dementia Research (Göttingen)},
ddc = {540},
cid = {I:(DE-2719)1440015},
pnm = {353 - Clinical and Health Care Research (POF4-353)},
pid = {G:(DE-HGF)POF4-353},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:39342994},
pmc = {pmc:PMC11602988},
doi = {10.1016/j.jbc.2024.107835},
url = {https://pub.dzne.de/record/273914},
}