DnaJ homolog subfamily B member 4 (DNAJB4)
The protein contains 337 amino acids for an estimated molecular weight of 37807 Da.
Probable chaperone. Stimulates ATP hydrolysis and the folding of unfolded proteins mediated by HSPA1A/B (in vitro) (PubMed:24318877). (updated: Oct. 25, 2017)
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.
- 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, is annotated as membranous in UniProt.
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The reference OMIM entry for this protein is 611327
Dnaj/hsp40 homolog, subfamily b, member 4; dnajb4
Human liver dnaj-like; hlj1
DESCRIPTION
DNAJB4 belongs to the evolutionarily conserved DNAJ/HSP40 protein family. For background information on the DNAJ family, see 608375.CLONING
Using the G protein beta subunit (GNB1; 139380) as bait in a yeast 2-hybrid screen of a liver cDNA library, Hoe et al. (1998) cloned DNAJB4, which they called HLJ1. The deduced 337-amino acid protein contains an N-terminal J domain and a glycine and phenylalanine (G/F)-rich region. It shares 84% sequence similarity with DNAJB1 (604572). Northern blot analysis detected high expression in skeletal muscle, heart, and pancreas, and lower expression in brain, placenta, and liver.GENE FUNCTION
By Northern blot analysis, Hoe et al. (1998) demonstrated that the expression of DNAJB4 increased following heat-shock treatment in human liver and pancreas carcinoma cell lines. E-cadherin (ECAD, or CDH1; 192090) is the main component of adherens junctions in epithelia and acts as the master regulator of cell-cell adhesion. Using a Drosophila-based genetic screen and transfected Chinese hamster ovary (CHO) cells, Simoes-Correia et al. (2014) showed that human DNAJB4 interacted with and functioned as a chaperone for Ecad, promoting its proper folding and plasma membrane localization. Silencing of Dnajb4 in CHO cells partly decreased expression of Ecad at the plasma membrane. Conversely, overexpression of human DNAJB4 increased plasma membrane expression of Ecad and increased cell-cell adhesion. DNAJB4 bound more strongly to an unfolded Ecad mutant and promoted its elimination in the proteasome via endoplasmic reticulum-associated degradation (ERAD). DNAJB4 appeared to distinguish between wildtype and unfolded mutant Ecad and to chaperone each appropriately to the plasma membrane or ERAD, respectively.MAPPING
Hartz (2007) mapped the DNAJB4 gene to chromosome 1p31.1 based on an alignment of the DNAJB4 sequence (GenBank GENBANK U40992) with the genomic sequence (build 36.1). ... More on the omim web site
Feb. 10, 2018: 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 611327 was added.