Transmembrane 9 superfamily member 2 (TM9SF2)
The protein contains 663 amino acids for an estimated molecular weight of 75776 Da.
In the intracellular compartments, may function as a channel or small molecule transporter. (updated: Oct. 10, 2018)
Protein identification was indicated in the following studies:
- 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.
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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No binding partner found
Cellular Component
Cytoskeleton
Endosome
Endosome membrane
Extracellular exosome
Golgi apparatus
Integral component of plasma membrane
Membrane
Postsynaptic Golgi apparatus
Molecular Function
The reference OMIM entry for this protein is 604678
Transmembrane 9 superfamily, member 2; tm9sf2
P76
CLONING
Endosomes are intracellular acidic compartments that participate in the sorting of proteins in the endocytic pathway. Proteins endocytosed from the plasma membrane are transported to early endosomes by clathrin-coated vesicles and then are either transported to lysosomes via late endosomes or recycled to the cell surface. In response to the low pH of the endosomes, endocytosed proteins undergo structural changes that affect their fate. Thus, the pH of the endosome, and therefore ion-translocating proteins in the endosome membrane, are important for endosome function. Using a yeast 2-hybrid system to identify proteins that interact preferentially with the active form of RAB9 (300284), Diaz et al. (1997) isolated a partial human cDNA encoding TM9SF2. By screening a Jurkat T-cell cDNA library with a fragment of the partial TM9SF2 cDNA, Schimmoller et al. (1998) isolated a cDNA containing the full-length coding sequence of TM9SF2, which they called p76. The deduced 663-amino acid TM9SF2 protein has a calculated molecular mass of 76 kD. TM9SF2 contains a putative signal sequence, a hydrophilic N-terminal region, and 9 predicted C-terminal transmembrane domains. The authors demonstrated that TM9SF2 adopts a type I topology within the membrane, with its hydrophilic N terminus facing the lumen. TM9SF2 shares 35% amino acid sequence identity with the S. cerevisiae Emp70 protein. By indirect immunofluorescence microscopy, recombinant TM9SF2 appeared to be localized to endosomes by virtue of its apparent colocalization with transferrin receptors (190010) and some mannose 6-phosphate receptors; TM9SF2 was not detected in the plasma membrane or in the Golgi apparatus. Northern blot analysis detected an approximately 3.2-kb TM9SF2 transcript in all human tissues tested, with the highest expression in pancreas, high expression in kidney, lower expression in heart, brain, skeletal muscle, and placenta, and the lowest expression in lung and liver. Schimmoller et al. (1998) suggested that TM9SF2 functions as an endosome ion channel or small molecule transporter.MAPPING
Gross (2014) mapped the TM9SF2 gene to chromosome 13q32.3 based on an alignment of the TM9SF2 sequence (GenBank GENBANK BC110656) with the genomic sequence (GRCh37). ... More on the omim web site
June 30, 2020: Protein entry updated
Automatic update: OMIM entry 604678 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).