Phosphatidylinositol transfer protein alpha isoform (PITPNA)
The protein contains 270 amino acids for an estimated molecular weight of 31806 Da.
Catalyzes the transfer of phosphatidylinositol (PI) and phosphatidylcholine (PC) between membranes (PubMed:10531358, PubMed:22822086, PubMed:15522822, PubMed:18636990, PubMed:14962392). Shows a preference for PI and PC containing shorter saturated or monosaturated acyl chains at the sn-1 and sn-2 positions (PubMed:15522822, PubMed:22822086). Preference order for PC is C16:1 > C16:0 > C18:1 > C18:0 > C20:4 and for PI is C16:1 > C16:0 > C18:1 > C18:0 > C20:4 > C20:3 (PubMed:22822086). (updated: Feb. 10, 2021)
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.
- 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.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
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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The reference OMIM entry for this protein is 600174
Phosphatidylinositol transfer protein, alpha; pitpna
Pitpn
DESCRIPTION
Phosphatidylinositol transfer protein is a member of a diverse set of cytosolic phospholipid transfer proteins that are distinguished by their ability to transfer phospholipids between membranes in vitro (Wirtz, 1991).CLONING
The rat Pitpna gene encodes a polypeptide of 271 amino acids and is expressed in a wide range of tissues (Dickeson et al., 1989). The protein predicted by the human PITPNA gene cloned and sequenced by Dickeson et al. (1994) showed only 3 amino acid sequence differences from the rat protein, 2 of which represented conservative substitutions. Hay and Martin (1993) reported studies suggesting that PITPNA is identical to priming-specific factor-3, one of the 3 priming factors involved in the ATP-dependent priming of Ca(2+)-activated secretion. Rat Pitpna shares 40% amino acid homology over its entire length with the Drosophila retinal degeneration B (rdgB) protein (Vihtelic et al., 1993). Flies carrying the rdgB mutation undergo light-enhanced retinal degeneration.MAPPING
As a first step toward investigations of possible involvement of the PITPNA locus in retinal degeneration, Fitzgibbon et al. (1994) mapped the PITPNA gene to human chromosome 17p13.3 by PCR analysis of a somatic cell hybrid panel followed by fluorescence in situ hybridization. They mapped the homologous gene to mouse chromosome 11 by interspecific mouse backcross mapping.ANIMAL MODEL
The mouse 'vibrator' (vb) mutation causes an early-onset progressive action tremor, degeneration of brainstem and spinal cord neurons, and juvenile death. Hamilton et al. (1997) cloned the vb mutation using an in vivo positional complementation approach followed by complete resequencing of the resulting 76-kb critical region in vb and its progenitor strain. The authors showed that the vb mutation is an intracisternal A particle retroposon insertion in intron 4 of the Pitpn gene, causing a 5-fold reduction in Pitpn RNA and protein levels. Expression of neurofilament light chain (NEFL; 162280) was also reduced in vb mice, suggesting 1 signaling pathway that may underlie vb pathology. The vb phenotype was suppressed in 1 intercross. By a complete genome scan, they mapped a major suppressor locus (Mvb1) to proximal mouse chromosome 19. The modifier-of-vibrator-1 locus (Mvb1) controls levels of correctly processed mRNA from genes mutated by endogenous retrovirus insertions into introns, including the Pitpn(vb) tremor mutation. By positional complementation cloning, Floyd et al. (2003) identified Mvb1 as the nuclear export factor Nxf1 (602647), providing an unexpected link between the mRNA export receptor and pre-mRNA processing. By examining lipid profiles, Monaco et al. (2004) observed increased neutral lipids, including cholesterol esters, triglycerides, and free fatty acids, in vb/vb liver compared with wildtype. No changes were detected in vb/vb liver phospholipid content or in the vb/vb brain lipid profile. Mammary glands of vb/vb mice were significantly underdeveloped compared with wildtype, and vb/vb mammary fat pads contained brown rather than white adipose tissue. No defect in phospholipid-mediated signaling was observed in isolated vb/vb fibroblasts. In Ptpa-null mice, Monaco et al. (2004) found reduced circulating triglycerides, overall reduction in body fat, low ATP/ADP ratio, and histologic evidence of steatosis in liver and duodenal tissue. Monaco et al. (2004) suggested that reduced Ptpa activity may res ... More on the omim web site
Feb. 16, 2021: Protein entry updated
Automatic update: Entry updated from uniprot information.
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 600174 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed