Zinc-alpha-2-glycoprotein (AZGP1)
The protein contains 298 amino acids for an estimated molecular weight of 34259 Da.
Stimulates lipid degradation in adipocytes and causes the extensive fat losses associated with some advanced cancers. May bind polyunsaturated fatty acids. (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.
- 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.
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.
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No binding partner found
Biological Process
Antigen processing and presentation
Antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-independent
Antigen processing and presentation of endogenous peptide antigen via MHC class Ib
Antigen processing and presentation of peptide antigen via MHC class I
Cell adhesion
Detection of chemical stimulus involved in sensory perception of bitter taste
Immune response
Negative regulation of cell population proliferation
Positive regulation of T cell mediated cytotoxicity
Protein transmembrane transport
Retina homeostasis
RNA phosphodiester bond hydrolysis
Transmembrane transport
The reference OMIM entry for this protein is 194460
Alpha-2-glycoprotein, zinc; azgp1
Zinc-alpha-2-glycoprotein; zag; za2g
CLONING
Burgi and Schmid (1961) first purified zinc-alpha-2-glycoprotein from pooled human plasma and studied its physicochemical properties. The glycoprotein was so named for its electrophoretic mobility in the alpha-2 region and for its ability to bind zinc ions. The ZAG glycoprotein has a molecular mass of 41 kD consisting of 18.2% carbohydrate and a single polypeptide chain. The complete amino acid sequence and the carbohydrate structure of ZAG were determined by Araki et al. (1988), who calculated the molecular mass to be 38,478 Da. Ueyama et al. (1991) isolated a cDNA clone for human zinc-alpha-2-glycoprotein. Southern blot analysis suggested the presence of a single gene encoding the protein.MAPPING
Using a panel of rodent-human somatic cell hybrids, Ueyama et al. (1991) assigned the ZAG gene to human chromosome 7. By fluorescence in situ hybridization, Ueyama et al. (1993) mapped the functional gene, which they symbolized ZA2G, to 7q22.1. They concluded that at least one of the pseudogenes is closely linked to the functional chain. Pendas et al. (1994) also used fluorescence in situ hybridization to map the AZGP1 gene to 7q22.GENE STRUCTURE
Freije et al. (1993) found that the AZGP1 gene spans over 9.7 kb and that its overall organization and nucleotide sequence resemble those of the first 4 exons of class I MHC genes (see 142800). However, it differs from those genes by its lack of coding information for transmembrane and cytoplasmic domains typical of MHC genes, which is consistent with its presence as a soluble protein in various physiologic and pathologic fluids. In addition, it contains a high density of repetitive sequences, including Alu, MER, and MIR elements, which are not present at equivalent positions in class I MHC genes. The human genome also contains a putative AZGP1 pseudogene. Ueyama et al. (1993) isolated the functional gene and found it to be 9.3 kb long and composed of 4 exons. The first exon codes for the 5-prime untranslated region, the signal sequence, and the first 6 amino acids. The second exon codes for domain A, the third for domain B, and the fourth for domain C and the 3-prime untranslated region. Ueyama et al. (1993) also isolated 2 pseudogenes retaining exon-intron organization.GENE FUNCTION
Freije et al. (1991) studied the expression of this protein in benign and malignant breast tissues. Freije et al. (1993) suggested that in light of the lack of polymorphism in the AZGP1 gene in comparison with MHC genes, this human glycoprotein may have a role in the transport of nonpolymorphic substances or in intercellular recognition processes.MOLECULAR GENETICS
Nakayashiki and Katsura (1989) studied ZAG in plasma by polyacrylamide gel isoelectric focusing followed by immunoblotting with specific antiserum to ZAG in the Japanese population. Most of 1,224 plasma samples showed a common, single-band pattern, whereas 16 samples showed variant double-band patterns which were classified into 4 types. The desialyzed form of ZAG commonly showed the single band. Differences in ZAG phenotypes appeared to be due to amino acid substitutions of the ZAG molecule. Nakayashiki and Katsura (1989) proposed the existence of 5 alleles, designated ZAG*1, ZAG*2, ZAG*3, ZAG*4 and ZAG*5, with frequencies of 0.9935, 0.0025, 0.0016, 0.0004, and 0.0020, respectively. The codominant transmission of the rare alleles ZAG*3 and ZAG*4 was confirmed in family studies. ... 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
June 20, 2017: Protein entry updated
Automatic update: comparative model was added.
March 25, 2017: Additional information
No protein expression data in P. Mayeux work for AZGP1
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 194460 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed