Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives
SLC6A14 (ATB<sup>0,+</sup>) is unique among SLC proteins in its ability to transport 18 of the 20 proteinogenic (dipolar and cationic) amino acids and naturally occurring and synthetic analogues (including anti-viral prodrugs and nitric oxide synthase (NOS) inhibitors). SLC6A14 mediates...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Biomolecules |
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| Online Access: | https://www.mdpi.com/2218-273X/12/10/1404 |
| _version_ | 1797474968187961344 |
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| author | Catriona M. H. Anderson Noel Edwards Andrew K. Watson Mike Althaus David T. Thwaites |
| author_facet | Catriona M. H. Anderson Noel Edwards Andrew K. Watson Mike Althaus David T. Thwaites |
| author_sort | Catriona M. H. Anderson |
| collection | DOAJ |
| description | SLC6A14 (ATB<sup>0,+</sup>) is unique among SLC proteins in its ability to transport 18 of the 20 proteinogenic (dipolar and cationic) amino acids and naturally occurring and synthetic analogues (including anti-viral prodrugs and nitric oxide synthase (NOS) inhibitors). SLC6A14 mediates amino acid uptake in multiple cell types where increased expression is associated with pathophysiological conditions including some cancers. Here, we investigated how a key position within the core LeuT-fold structure of SLC6A14 influences substrate specificity. Homology modelling and sequence analysis identified the transmembrane domain 3 residue V128 as equivalent to a position known to influence substrate specificity in distantly related SLC36 and SLC38 amino acid transporters. SLC6A14, with and without V128 mutations, was heterologously expressed and function determined by radiotracer solute uptake and electrophysiological measurement of transporter-associated current. Substituting the amino acid residue occupying the SLC6A14 128 position modified the binding pocket environment and selectively disrupted transport of cationic (but not dipolar) amino acids and related NOS inhibitors. By understanding the molecular basis of amino acid transporter substrate specificity we can improve knowledge of how this multi-functional transporter can be targeted and how the LeuT-fold facilitates such diversity in function among the SLC6 family and other SLC amino acid transporters. |
| first_indexed | 2024-03-09T20:37:26Z |
| format | Article |
| id | doaj.art-e25bf220a65546b59212d9766070a338 |
| institution | Directory Open Access Journal |
| issn | 2218-273X |
| language | English |
| last_indexed | 2024-03-09T20:37:26Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Biomolecules |
| spelling | doaj.art-e25bf220a65546b59212d9766070a3382023-11-23T23:08:07ZengMDPI AGBiomolecules2218-273X2022-10-011210140410.3390/biom12101404Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and DerivativesCatriona M. H. Anderson0Noel Edwards1Andrew K. Watson2Mike Althaus3David T. Thwaites4School of Natural & Environmental Sciences, Faculty of Science, Engineering & Agriculture, Newcastle University, Newcastle upon Tyne NE1 7RU, UKBiosciences Institute, Faculty of Medical Sciences, Framlington Place, Newcastle University, Newcastle upon Tyne NE2 4HH, UKBiosciences Institute, Faculty of Medical Sciences, Framlington Place, Newcastle University, Newcastle upon Tyne NE2 4HH, UKSchool of Natural & Environmental Sciences, Faculty of Science, Engineering & Agriculture, Newcastle University, Newcastle upon Tyne NE1 7RU, UKBiosciences Institute, Faculty of Medical Sciences, Framlington Place, Newcastle University, Newcastle upon Tyne NE2 4HH, UKSLC6A14 (ATB<sup>0,+</sup>) is unique among SLC proteins in its ability to transport 18 of the 20 proteinogenic (dipolar and cationic) amino acids and naturally occurring and synthetic analogues (including anti-viral prodrugs and nitric oxide synthase (NOS) inhibitors). SLC6A14 mediates amino acid uptake in multiple cell types where increased expression is associated with pathophysiological conditions including some cancers. Here, we investigated how a key position within the core LeuT-fold structure of SLC6A14 influences substrate specificity. Homology modelling and sequence analysis identified the transmembrane domain 3 residue V128 as equivalent to a position known to influence substrate specificity in distantly related SLC36 and SLC38 amino acid transporters. SLC6A14, with and without V128 mutations, was heterologously expressed and function determined by radiotracer solute uptake and electrophysiological measurement of transporter-associated current. Substituting the amino acid residue occupying the SLC6A14 128 position modified the binding pocket environment and selectively disrupted transport of cationic (but not dipolar) amino acids and related NOS inhibitors. By understanding the molecular basis of amino acid transporter substrate specificity we can improve knowledge of how this multi-functional transporter can be targeted and how the LeuT-fold facilitates such diversity in function among the SLC6 family and other SLC amino acid transporters.https://www.mdpi.com/2218-273X/12/10/1404amino acid transportersolute carrierSLCmembrane transportSLC6A14SLC6 |
| spellingShingle | Catriona M. H. Anderson Noel Edwards Andrew K. Watson Mike Althaus David T. Thwaites Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives Biomolecules amino acid transporter solute carrier SLC membrane transport SLC6A14 SLC6 |
| title | Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives |
| title_full | Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives |
| title_fullStr | Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives |
| title_full_unstemmed | Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives |
| title_short | Reshaping the Binding Pocket of the Neurotransmitter:Solute Symporter (NSS) Family Transporter SLC6A14 (ATB<sup>0,+</sup>) Selectively Reduces Access for Cationic Amino Acids and Derivatives |
| title_sort | reshaping the binding pocket of the neurotransmitter solute symporter nss family transporter slc6a14 atb sup 0 sup selectively reduces access for cationic amino acids and derivatives |
| topic | amino acid transporter solute carrier SLC membrane transport SLC6A14 SLC6 |
| url | https://www.mdpi.com/2218-273X/12/10/1404 |
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