scholarly journals Structural Features of the Glutamate Transporter Family

1999 ◽  
Vol 63 (2) ◽  
pp. 293-307 ◽  
Author(s):  
Dirk Jan Slotboom ◽  
Wil N. Konings ◽  
Juke S. Lolkema
Keyword(s):  
Amino Acid ◽  
Glutamate Transporter ◽  
Glutamate Transporters ◽  
Amino Acid Sequences ◽  
Neutral Amino Acid ◽  
Amino Acid Transporters ◽  
Conserved Sequence ◽  
Transporter Family ◽  
The Family ◽  
Membrane Spanning

SUMMARY Neuronal and glial glutamate transporters remove the excitatory neurotransmitter glutamate from the synaptic cleft and thus prevent neurotoxicity. The proteins belong to a large and widespread family of secondary transporters, including bacterial glutamate, serine, and C4-dicarboxylate transporters; mammalian neutral-amino-acid transporters; and an increasing number of bacterial, archaeal, and eukaryotic proteins that have not yet been functionally characterized. Sixty members of the glutamate transporter family were found in the databases on the basis of sequence homology. The amino acid sequences of the carriers have diverged enormously. Homology between the members of the family is most apparent in a stretch of approximately 150 residues in the C-terminal part of the proteins. This region contains four reasonably well-conserved sequence motifs, all of which have been suggested to be part of the translocation pore or substrate binding site. Phylogenetic analysis of the C-terminal stretch revealed the presence of five subfamilies with characterized members: (i) the eukaryotic glutamate transporters, (ii) the bacterial glutamate transporters, (iii) the eukaryotic neutral-amino-acid transporters, (iv) the bacterial C4-dicarboxylate transporters, and (v) the bacterial serine transporters. A number of other subfamilies that do not contain characterized members have been defined. In contrast to their amino acid sequences, the hydropathy profiles of the members of the family are extremely well conserved. Analysis of the hydropathy profiles has suggested that the glutamate transporters have a global structure that is unique among secondary transporters. Experimentally, the unique structure of the transporters was recently confirmed by membrane topology studies. Although there is still controversy about part of the topology, the most likely model predicts the presence of eight membrane-spanning α-helices and a loop-pore structure which is unique among secondary transporters but may resemble loop-pores found in ion channels. A second distinctive structural feature is the presence of a highly amphipathic membrane-spanning helix that provides a hydrophilic path through the membrane. Recent data from analysis of site-directed mutants and studies on the mechanism and pharmacology of the transporters are discussed in relation to the structural model.

scholarly journals Oligomeric structure of the neutral amino acid transporters KAAT1 and CAATCH1

2007 ◽  
Vol 292 (4) ◽  
pp. C1379-C1387 ◽  
Author(s):  
Elena Bossi ◽  
Andrea Soragna ◽  
Andreea Miszner ◽  
Stefano Giovannardi ◽  
Valeria Frangione ◽  
...  
Keyword(s):  
Amino Acid ◽  
Fluorescent Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Neutral Amino Acid ◽  
Amino Acid Transporters ◽  
Functional Studies ◽  
Transporter Family ◽  
Covalently Linked ◽  
Monomeric Proteins

The highly homologous neutral amino acid transporters KAAT1 and CAATCH1, cloned from the midgut epithelium of the Manduca sexta larva, are members of the Na+/Cl−-dependent transporter family. Recent evidence indicates that transporters of this family form constitutive oligomers. CAATCH1 and KAAT1 give rise to specific kinds of current depending on the transported amino acid, cotransported ion, pH, and membrane voltage. Different substrates induce notably distinct transport-associated currents in the two proteins that represent useful tools in structural-functional studies. To determine whether KAAT1 and CAATCH1 form functional oligomers, we have constructed four concatameric proteins for electrophysiological analysis, consisting of one KAAT1 protein covalently linked to another KAAT1 (K-K concatamer) or to CAATCH1 (K-C concatamer) and vice versa (C-C concatamer and C-K concatamer), and eight constructs where the two transporters were linked to yellow or cyan fluorescent protein in the NH2 or COOH terminus, to determine the oligomer formation and the relative distance between the different subunits by fluorescence resonance energy transfer (FRET) analysis. Heterologous expression of the concatenated constructs and coinjection of the original proteins in different proportions allowed us to compare the characteristics of the currents to those of the oocytes expressing only the wild-type proteins. All the constructs were fully active, and their electrophysiological behavior was consistent with the activity as monomeric proteins. However, the FRET studies indicate that these transporters form oligomers in agreement with the LeuTAa atomic structure and confirm that the COOH termini of the adjacent subunits are closer than NH2 termini.

scholarly journals SLC1 family of amino acid transporters (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Philip M. Beart
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Glutamate Transporters ◽  
Neutral Amino Acid ◽  
Amino Acid Transporters ◽  
Sodium Dependent

The SLC1 family of sodium dependent transporters includes the plasma membrane located glutamate transporters and the neutral amino acid transporters ASCT1 and ASCT2 [1, 49, 36, 37, 7].

The SLC1 high-affinity glutamate and neutral amino acid transporter family

2013 ◽  
Vol 34 (2-3) ◽  
pp. 108-120 ◽  
Author(s):  
Yoshikatsu Kanai ◽  
Benjamin Clémençon ◽  
Alexandre Simonin ◽  
Michele Leuenberger ◽  
Martin Lochner ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Transporter ◽  
Neutral Amino Acid ◽  
High Affinity ◽  
Neutral Amino Acid Transporter ◽  
Transporter Family ◽  
Acid Transporter

Complete Genome Sequence of a Novel Ourmia-like Mycovirus Infecting the Phytopathogenic Fungus Botryosphaeria Dothidea

2021 ◽  
Author(s):  
Liying Sun ◽  
Ziqian Lian ◽  
Subha Das ◽  
Jingxian Luo ◽  
Ida Bagus Andika
Keyword(s):  
Amino Acid ◽  
Genome Sequence ◽  
Amino Acid Sequences ◽  
Shanxi Province ◽  
Phytopathogenic Fungus ◽  
Botryosphaeria Dothidea ◽  
Reading Frame ◽  
Ring Rot ◽  
Ssrna Virus ◽  
The Family

Abstract In this study, we describe the full-length genome sequence of a novel ourmia-like mycovirus, tentatively designated Botryosphaeria dothidea ourmia-like virus 1 (BdOLV1), isolated from the phytopathogenic fungus, Botryosphaeria dothidea strain P8, associated with apple ring rot in Shanxi province, China. The complete BdOLV1 genome is comprised of 2797 nucleotides, a positive-sense (+) single-stranded RNA (ssRNA) with a single open reading frame (ORF). The ORF putatively encodes a 642-amino acid polypeptide with conserved RNA-dependent RNA polymerase (RdRp) motifs, related to viruses of the family Botourmiaviridae. Phylogenetic analysis based on the RdRp amino acid sequences showed that BdOLV1 is grouped with oomycete-infecting unclassified viruses closely related to the genus Botoulivirus in Botourmiaviridae. This is the first report of a novel (+)ssRNA virus in B. dothidea related to the genus Botoulivirus in the family Botourmiaviridae.

scholarly journals Taxonomic status of Bhanja and Kismayo viruses (family Bunyaviridae)

2012 ◽  
Vol 17 (4) ◽  
pp. 4-8
Author(s):  
A. S Klimentov ◽  
A. P Gmyl ◽  
A. M Butenko ◽  
L. V Gmyl ◽  
O. V Isaeva ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Amino Acid ◽  
Nucleotide Sequence ◽  
Taxonomic Status ◽  
Amino Acid Sequences ◽  
The Family ◽  
L Segment

The nucleotide sequence of M= (1398 nucleotides and L= (6186 nucleotides) segments of the genome of Bhanja virus and L-segment (1297 nucleotides) of Kismayo virus has been partially determined. Phylogenetic analysis of deduced amino acid sequences showed that these viruses are novel members of the Flebovirus (Phlebovirus) genus in the family Bunyaviridae

scholarly journals Inhibitors of the Neutral Amino Acid Transporters ASCT1 and ASCT2 Are Effective in In Vivo Models of Schizophrenia and Visual Dysfunction

2018 ◽  
Vol 367 (2) ◽  
pp. 292-301 ◽  
Author(s):  
Yong-Xin Li ◽  
Jia-Ying Yang ◽  
Miguel Alcantara ◽  
Grigor Abelian ◽  
Ashutosh Kulkarni ◽  
...  
Keyword(s):  
Amino Acid ◽  
Neutral Amino Acid ◽  
Amino Acid Transporters ◽  
Visual Dysfunction ◽  
In Vivo Models

Na(+)-independent transport (uniport) of amino acids and glucose in mammalian cells.

1994 ◽  
Vol 196 (1) ◽  
pp. 93-108
Author(s):  
D K Kakuda ◽  
C L MacLeod
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Mammalian Cells ◽  
Glucose Transporter ◽  
Sequence Similarity ◽  
Amino Acid Sequence Similarity ◽  
Amino Acid Transporters ◽  
Cationic Amino Acid ◽  
Transporter Family ◽  
Share Amino Acid Sequence

Recent advances have made possible the isolation of the genes and their cDNAs encoding Na(+)-independent amino acid transporters. Two classes of amino acid 'uniporters' have been isolated. One class contains the mCAT (murine cationic amino acid transporter) gene family that encodes proteins predicted to span the membrane 12-14 times and exhibits structural properties similar to the GLUT (glucose transporter) family and to other well-known transporters. The other class consists of two known genes, rBAT (related to B system amino acid transporters) and 4F2hc, that share amino acid sequence similarity with alpha-amylases and alpha-glucosidases. They are type II glycoproteins predicted to span the membrane only once, yet they mediate the Na(+)-independent transport of cationic and zwitterionic amino acids in Xenopus oocytes. Mutations in the human rBAT gene have been identified by Palacín and his co-workers in several families suffering from a heritable form of cystinuria. This important finding clearly establishes a key role for rBAT in cystine transport. The two classes of amino acid transporters are compared with the well-studied GLUT family of Na(+)-independent glucose transporters.

Partial Proteolysis of Rice Phytochrome: Comparison with Oat Phytochrome

1989 ◽  
Vol 44 (9-10) ◽  
pp. 757-764 ◽  
Author(s):  
Rudolf Schendel ◽  
Zhe Tong ◽  
Wolfhart Rüdiger
Keyword(s):  
Signal Transduction ◽  
Oryza Sativa ◽  
Amino Acid ◽  
Spectral Data ◽  
Active Center ◽  
Oryza Sativa L ◽  
Slight Modification ◽  
Amino Acid Sequences ◽  
Rice Seedlings ◽  
Conserved Sequence

Phytochrome was isolated from etiolated rice seedlings (Oryza sativa L.) by slight modification of the procedure for oat phytochrome. Spectral data of rice phytochrome are comparable with those of oat and rye phytochrome. Controlled proteolysis with endoproteinases Lys-C and Glu-C yielded defined fragments some of which were different for Pr and Pfr. The fragments were identified by comparison with the corresponding fragments of oat phytochrome and by comparison of the amino acid sequences of rice and oat phytochrome. Regions of the peptide chain which are differently exposed in Pr and Pfr were identified. A highly conserved sequence around residues 740-750 is discussed as candidate for an ‘‘active center’’ of signal transduction.

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