Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-2 (GNB2)
The protein contains 340 amino acids for an estimated molecular weight of 37331 Da.
Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction. (updated: April 1, 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.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- 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.
This protein is annotated as membranous in Gene Ontology.
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Biological Process
Cellular response to glucagon stimulus
Chemical synaptic transmission
Energy reserve metabolic process
G protein-coupled receptor signaling pathway
Protein folding
Small molecule metabolic process
The reference OMIM entry for this protein is 139390
Guanine nucleotide-binding protein, beta-2; gnb2
DESCRIPTION
Heterotrimeric G proteins, made up of an alpha subunit (see GNAS, 139320), a beta subunit, like GNB2, and a gamma subunit (see GNG2, 606981), relay signals from cell surface receptors to internal effectors. The alpha subunit is a GTPase that interacts in the GDP-bound state with beta-gamma dimers (Rosskopf et al., 2003).CLONING
Gao et al. (1987) isolated a cDNA that encodes a second form of the beta-subunit of signal-transducing guanine nucleotide-binding regulatory proteins (G proteins). The cDNA corresponded to a 1.8-kb mRNA, and nucleotide sequence analysis indicated that the encoded polypeptide consists of 340 amino acid residues with a molecular weight of 37,335. Although the deduced polypeptide was found to be of the same size as that reported previously for the beta subunit (beta-1), 10% of the amino acid residues were different.GENE FUNCTION
Peng et al. (1992) pointed out that although the alpha subunit shows great diversity and is thought to confer functional specificity to a particular G protein, the beta subunit, which is much less diverse, is believed to have no role in G protein specificity. Using immunocytochemistry, they found, however, distinct distribution patterns for different beta and gamma subunits in the retina. In particular, rod and cone photoreceptors, which both subserve phototransduction but differ in light-response properties, have different beta and gamma subunits in their outer segments. Thus, the G protein mediating phototransduction shows cell-specific forms of the beta and gamma subunits in addition to the alpha subunit. This surprising finding supported the hypothesis that these subunits contribute to functional specificity of the G protein. Wolfe et al. (2003) demonstrated that inhibition of the alpha-1H (Ca(v)3.2) (CACNA1H; 607904), but not alpha-1G (Ca(v)3.1) (CACNA1G; 604065), low voltage-activated calcium channels is mediated selectively by G protein beta-2-gamma-2 subunits (GNB2 and GNG2) subunits that bind to the intracellular loop connecting channel transmembrane domains II and III. This region of the alpha-1H channel is crucial for inhibition, because its replacement abrogates inhibition and its transfer to nonmodulated alpha-1G channels confers beta-2-gamma-2-dependent inhibition. Beta-gamma reduces channel activity independent of voltage, a mechanism distinct from the established beta-gamma-dependent inhibition of non-L-type high voltage-activated channels of the Ca(v)2 family. Wolfe et al. (2003) concluded that their studies identified the alpha-1H channel as a new effector for G protein beta-gamma subunits, and highlight the selective signaling roles available for particular beta-gamma combinations.GENE STRUCTURE
Rosskopf et al. (2003) determined that the GNB2 gene contains 10 exons. The first exon is noncoding.MAPPING
Blatt et al. (1988) assigned the GNB2 gene to human chromosome 7 by hybridization of clones to DNA from somatic cell hybrids. By studying a YAC containing the EPO gene (133170), Kere et al. (1991) demonstrated that the GNB2 gene is located within 30 to 80 kb of EPO and most likely centromeric of it. GNAI1 (139310) is located in the same area. Lovett et al. (1991) developed a strategy for the rapid enrichment and identification of cDNAs encoded by large genomic regions. The basis of this 'direct selection' scheme was the hybridization of an entire library of cDNAs to an immobilized genomic clone. The scheme ... 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
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 GNB2
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 139390 was added.