SEC14-like protein 2 (SEC14L2)
The protein contains 403 amino acids for an estimated molecular weight of 46145 Da.
Carrier protein. Binds to some hydrophobic molecules and promotes their transfer between the different cellular sites. Binds with high affinity to alpha-tocopherol. Also binds with a weaker affinity to other tocopherols and to tocotrienols. May have a transcriptional activatory activity via its association with alpha-tocopherol. Probably recognizes and binds some squalene structure, suggesting that it may regulate cholesterol biosynthesis by increasing the transfer of squalene to a metabolic active pool in the cell. (updated: March 4, 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.
- 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.
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.
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| Variant | Description |
|---|---|
| dbSNP:rs757660 |
No binding partner found
Biological Process
Positive regulation of transcription, DNA-templated
Regulation of cholesterol biosynthetic process
Transcription, DNA-templated
Cellular Component
Cytoplasm
Cytosol
Extracellular exosome
Integral component of membrane
Nucleoplasm
Nucleus
The reference OMIM entry for this protein is 607558
Sec14-like 2; sec14l2
Sec14, s. cerevisiae, homolog of, 2
Tocopherol-associated protein 1; tap1
Tap kiaa1186
CLONING
By sequencing clones obtained from a size-fractionated human brain cDNA library, Hirosawa et al. (1999) cloned a partial cDNA encoding SEC14L2, which they designated KIAA1186. RT-PCR followed by ELISA detected moderate expression in kidney, spleen, testis, ovary, and fetal liver. Lower levels were detected in whole brain, lung, and adult liver. Zimmer et al. (2000) sequenced peptide fragments from bovine SEC14L2, which they called TAP, and searched a database using these sequences to identify human TAP. Using RT-PCR they cloned full-length TAP from human small intestine total RNA. The deduced 403-amino acid protein has a calculated molecular mass of about 46 kD and contains a conserved hydrophobic lipid-binding pocket called the CRAL (cis-retinal binding)/TRIO (triple function) domain. Human and bovine TAP share about 84% amino acid identity. mRNA dot blot analysis detected broad tissue distribution, with highest expression in liver, prostate, and brain. Northern blot analysis detected a major transcript of 2.8 kb and 2 minor transcripts of approximately 4.2 and 2.8 kb expressed at highest levels in liver and brain and more weakly in kidney. By immunocytochemical studies, Kempna et al. (2003) showed that SEC14L2 localized to intracellular membranes of the cytoplasm in HeLa cells, including partial localization to the ER and Golgi, with more intense staining surrounding but not within the nucleus.GENE FUNCTION
Using a biotinylated alpha-tocopherol derivative, Zimmer et al. (2000) demonstrated that recombinant TAP binds alpha-tocopherol at physiologic concentrations. Binding was dose dependent and saturable. By ligand competition analysis, Yamauchi et al. (2001) confirmed specific interaction between recombinant TAP and alpha-tocopherol. TAP did not significantly interact with any other tocopherols or tocotrienols examined. Alpha-tocopherol induced the translocation of TAP from the cytosol to the nucleus of transfected COS-7 cells. Transient transfection experiments showed that TAP activated transcription of a reporter gene in an alpha-tocopherol-dependent manner. Yamauchi et al. (2001) hypothesized that alpha-tocopherol is not only an antioxidant, but also a transcriptional regulator via its association with TAP. Kempna et al. (2003) showed that in HeLa cells deletion of the C-terminal Golgi dynamics (GOLD) domain reduced SEC14L2 localization in the region surrounding the nucleus with some tubular sacs emerging. They suggested that the SEC14L2 GOLD domain may play a role in docking to other proteins or in intracellular transport of bound ligands. Using several assays, Kempna et al. (2003) demonstrated that SEC14L2 bound tocopherol, squalene, and phospholipids (phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol). Although SEC14L2 bound phospholipids, it failed to complement an S. cerevisiae temperature-sensitive Sec14 allele in yeast. Using immunoprecipitation assays, Kempna et al. (2003) showed that SEC14L2 may interact with and regulate phosphatidylinositol 3-kinase activity, and SEC14L2 displayed low basal GTPase activity.GENE STRUCTURE
Zimmer et al. (2000) determined that the SEC14L2 gene contains 12 exons.MAPPING
By radiation hybrid analysis, Hirosawa et al. (1999) mapped the SEC14L2 gene to chromosome 22. By genomic sequence analysis, Zimmer et al. (2000) mapped the SEC14L2 gene to chromosome 22q12.1-qter. ... 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
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 607558 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed