Journal Article

DZNE-2024-01388

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Comprehensive characterization of the OCT1 phenylalanine-244-alanine substitution reveals highly substrate-dependent effects on transporter function.

Wittern, C. I. ; Schröder, S.DZNE* ; Jensen, O. ; Brockmöller, J. ; Gebauer, L.

2024
Soc. Bethesda, Md.

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Please use a persistent id in citations: doi:10.1016/j.jbc.2024.107835

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.

Keyword(s): Humans (MeSH) ; Phenylalanine: metabolism (MeSH) ; Phenylalanine: chemistry (MeSH) ; Amino Acid Substitution (MeSH) ; Substrate Specificity (MeSH) ; HEK293 Cells (MeSH) ; Alanine: metabolism (MeSH) ; Alanine: chemistry (MeSH) ; Kinetics (MeSH) ; Biological Transport (MeSH) ; Organic Cation Transporter 1: metabolism (MeSH) ; Organic Cation Transporter 1: genetics (MeSH) ; Organic Cation Transporter 1: chemistry (MeSH) ; alanine mutagenesis ; binding pocket ; inhibition ; organic cation transporter 1 ; polyspecificity ; site-directed mutagenesis ; transport ; Phenylalanine ; Alanine ; Organic Cation Transporter 1

Note: ISSN 0021-9258 not unique: **2 hits**.

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Contributing Institute(s):

1. Clinical Dementia Research (Göttingen) (Clinical Dementia Research (Göttingen))

Research Program(s):

1. 353 - Clinical and Health Care Research (POF4-353) (POF4-353)

Appears in the scientific report 2024

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Database coverage:
; ; ; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; PubMed Central ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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