Large neutral amino acids transporter small subunit 4 (SLC43A2)
The protein contains 569 amino acids for an estimated molecular weight of 62747 Da.
Sodium-, chloride-, and pH-independent high affinity transport of large neutral amino acids. (updated: April 1, 2015)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
This protein is annotated as membranous in Gene Ontology, is predicted to be membranous by TOPCONS.
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No binding partner found
Biological Process
Amino acid transport
Ion transport
Negative regulation of amino acid transport
Negative regulation of leucine import
Neutral amino acid transport
Transmembrane transport
Cellular Component
Integral component of membrane
Integral component of plasma membrane
Plasma membrane
The reference OMIM entry for this protein is 610791
Solute carrier family 43 (l-type amino acid transporter), member 2; slc43a2
L-type amino acid transporter 4; lat4
DESCRIPTION
System L amino acid transporters, such as SLC43A2, mediate sodium-independent transport of bulky neutral amino acids across cell membranes (Bodoy et al., 2005).CLONING
By searching a database for sequences similar to LAT3 (SLC43A1; 603733), Bodoy et al. (2005) identified SLC43A2, which they called LAT4. The deduced 569-amino acid protein has a calculated molecular mass of 62.7 kD. LAT4 has 12 transmembrane domains with intracellular N and C termini, and a putative N-glycosylation site is located in the extracellular loop between the first 2 transmembrane domains. It shares 57% amino acid identity with LAT3 and 91% identity with mouse Lat4. Northern blot analysis of human tissues detected transcripts of 3.1 and 8 to 9 kb, with highest expression in placenta, followed by kidney and peripheral blood leukocytes. In mouse tissues, expression was highest in small intestine. Immunofluorescence analysis detected LAT4 on the plasma membrane of transfected HeLa cells. In situ hybridization of human kidney showed LAT4 mRNA restricted to epithelial cells of the distal tubule and collecting duct. In mouse intestine, Lat4 was mainly expressed in crypt cells of the intestinal microvilli and in epithelial cells at the base of the villus. Western blot analysis of transfected HeLa cells showed that endoglycosidase treatment reduced the molecular mass of LAT4, confirming that LAT4 is glycosylated.GENE FUNCTION
Bodoy et al. (2005) found that injection of human LAT4 cRNA into Xenopus oocytes resulted in increased uptake of L-phenylalanine, L-leucine, L-isoleucine, and L-methionine. L-phenylalanine transport was independent of chloride, sodium, and pH. Kinetic analysis of L-phenylalanine and L-leucine transport activity revealed a low-affinity component that was sensitive to the sulfhydryl-specific reagent N-ethylmaleimide and a high-affinity component that was not. Substitution of the conserved ser297 in the large intracellular loop of LAT4 with ala partially inhibited transport activity and abolished the sensitivity to N-ethylmaleimide. Lat4 activity localized to basolateral membranes in cultured mouse proximal collecting tubule kidney cells.MAPPING
Hartz (2007) mapped the SLC43A2 gene to chromosome 17p13.3 based on an alignment of the SLC43A2 sequence (GenBank GENBANK AB120364) with the genomic sequence (build 36.1). ... More on the omim web site
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 25, 2017: Additional information
No protein expression data in P. Mayeux work for SLC43A2
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 610791 was added.