Polypeptide N-acetylgalactosaminyltransferase 2 (GALNT2)
The protein contains 571 amino acids for an estimated molecular weight of 64733 Da.
Catalyzes the initial reaction in O-linked oligosaccharide biosynthesis, the transfer of an N-acetyl-D-galactosamine residue to a serine or threonine residue on the protein receptor. Has a broad spectrum of substrates for peptides such as EA2, Muc5AC, Muc1a, Muc1b. Probably involved in O-linked glycosylation of the immunoglobulin A1 (IgA1) hinge region. Involved in O-linked glycosylation of APOC-III, ANGPTL3 and PLTP. It participates to the regulation of HDL-C metabolism (PubMed:27508872, PubMed:32293671). (updated: April 7, 2021)
Protein identification was indicated in the following studies:
- 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.
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 predicted to be membranous by TOPCONS.
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Biological Process
Immunoglobulin biosynthetic process
O-glycan processing
Protein maturation
Protein O-linked glycosylation
Protein O-linked glycosylation via serine
Protein O-linked glycosylation via threonine
The reference OMIM entry for this protein is 602274
Udp-n-acetyl-alpha-d-galactosamine:polypeptide n-acetylgalactosaminyltransferase 2; galnt2
Galnac transferase 2; galnact2
DESCRIPTION
Membrane-bound polypeptide N-acetylgalactosaminyltransferases (EC 2.4.1.41), such as GALNT2, catalyze the first step in mucin-type O-glycosylation of peptides in the Golgi apparatus. These enzymes transfer N-acetylgalactosamine (GalNAc) from UDP-GalNAc to the hydroxyl group of serine or threonine in target proteins (summary by Peng et al., 2010).CLONING
White et al. (1995) purified GALNT2, termed GalNAc-T2 by them, from human placenta, using a defined synthetic acceptor peptide as an affinity ligand. They also identified a cDNA for GALNT2 using polymerase chain reaction with primers derived from the protein sequence of the purified GALNT2. The GALNT2 cDNA encodes a predicted 571-amino acid protein of approximately 64 kD.GENE FUNCTION
Using recombinant human enzymes and UDP-GalNAc as sugar donor, Cheng et al. (2004) compared the catalytic activities of GALNT2 and GALNT15 (615131). The 2 enzymes exhibited distinct substrate specificities against a panel of synthetic peptide acceptor substrates. They also differed in site-specific and order-specific GalNAc incorporation. In general, GALNT15 had weaker catalytic activity than GALNT2. However, GALNT15 transferred up to 7 GalNAc resides onto a peptide derived from MUC5AC (158373), whereas GALNT2 transferred only 5.GENE STRUCTURE
Bennett et al. (1998) found that the GALNT1 (602273), GALNT2, and GALNT3 (601756) genes contain 11, 16, and 10 exons, respectively. Several intron/exon boundaries are conserved within the 3 genes.MAPPING
By FISH, Bennett et al. (1998) mapped the GALNT2 gene to chromosome 1q41-q42. ... More on the omim web site
April 10, 2021: Protein entry updated
Automatic update: Entry updated from uniprot information.
Nov. 17, 2018: Protein entry updated
Automatic update: OMIM entry 602274 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).