Ferritin light chain (FTL)
The protein contains 175 amino acids for an estimated molecular weight of 20020 Da.
Stores iron in a soluble, non-toxic, readily available form. Important for iron homeostasis. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation. Also plays a role in delivery of iron to cells. Mediates iron uptake in capsule cells of the developing kidney (By similarity). (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.
- 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.
- 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.
Biological Process
Cellular iron ion homeostasis
Intracellular sequestering of iron ion
Iron ion homeostasis
Iron ion transport
Membrane organization
Neutrophil degranulation
Oxidation-reduction process
Post-Golgi vesicle-mediated transport
Receptor-mediated endocytosis
Transmembrane transport
The reference OMIM entry for this protein is 134790
Ferritin light chain; ftl
DESCRIPTION
The iron storage protein ferritin is a complex of 24 L-ferritin (FTL) and H-ferritin (FTH1; 134770) subunits in ratios that vary in different cell types. FTH subunits exhibit ferroxidase activity, converting Fe(2+) to Fe(3+), so that iron may be stored in the ferritin mineral core, which prevents undesirable reactions of Fe(2+) with oxygen. FTL subunits are devoid of catalytic activity but are thought to facilitate nucleation and mineralization of the iron center (summary by Sammarco et al., 2008).CLONING
Studies of ferritin synthesis in cell-free systems by Watanabe and Drysdale (1981) suggested that the H and L subunits in human and rat are derived from different mRNA molecules. Brown et al. (1983) noted that mammalian liver and spleen ferritin (relative mass about 450 kD) consists of 24 subunits of 2 species, the heavy subunit (relative mass, 21 kD) and the light subunit (relative mass, 19 kD). They presented evidence that, in rat, the 2 subunits are coded by separate mRNAs and that a family of genes encodes the light subunit. Cazzola et al. (1997) stated that the human ferritin L chain contains 174 residues and has an apparent molecular mass of 19 kD. They found that serum ferritin, with an apparent molecular mass of 23 kD, was a glycosylated form of intracellular ferritin L chain. Curtis et al. (2001) reported that the human ferritin light chain contains 175 residues and that the peptide folds into 5 alpha-helical domains designated A through E.MAPPING
By study of human/Chinese hamster hybrid cells and use of a radioimmunoassay specific for human ferritin, Caskey et al. (1983) showed that chromosome 19 encodes the structural gene for ferritin. By in situ hybridization, McGill et al. (1984) confirmed the assignment of the light chain gene to chromosome 19 but concluded that the heavy chain is encoded by 1p. By study of hamster-human and mouse-human hybrid cells, some with translocations involving chromosome 19, Worwood et al. (1985) concluded that light subunits of ferritin (rich in human spleen ferritin) are coded by a gene in segment 19q13.3-qter and that the gene for the heavy subunit (rich in human heart ferritin) is located on chromosome 11. By miniaturized restriction enzyme analysis of sorted chromosomes, Lebo et al. (1985) demonstrated ferritin light-chain genes on at least 3 chromosomes. Munro et al. (1988) reviewed information on the ferritin genes. They pointed out that in both the rat and the human, several ferritin pseudogenes can be recognized not only because they are flanked by 5-prime and 3-prime direct repeats representing the site of their retroinsertion into the chromatin, but also because they differ from functional genes by the absence of introns and by the presence of polyadenylic acid tails that have been inserted onto the 3-prime end of the messenger transcription of the functional gene. They cited the evidence of Santoro et al. (1986) and of Hentze et al. (1986) that there is only one expressed H and one expressed L gene in the human genome. By typing the progeny of 2 sets of genetic crosses, Filie et al. (1998) determined the map location of loci containing sequences related to the ferritin light chain gene in the mouse. Twelve loci were positioned on 11 different chromosomes. One of these genes mapped to a position on chromosome 7 predicted to contain the expressed Flt1 gene on the basis of the previously determined position of the human homolog on 19q13.3-q1 ... 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 16, 2016: Protein entry updated
Automatic update: OMIM entry 134790 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 24, 2016: Protein entry updated
Automatic update: model status changed