Type 1 phosphatidylinositol 4,5-bisphosphate 4-phosphatase (TMEM55B)
The protein contains 277 amino acids for an estimated molecular weight of 29470 Da.
Catalyzes the hydrolysis of phosphatidylinositol-4,5-bisphosphate (PtdIns-4,5-P2) to phosphatidylinositol-4-phosphate (PtdIns-4-P) (PubMed:16365287). Does not hydrolyze phosphatidylinositol 3,4,5-trisphosphate, phosphatidylinositol 3,4-bisphosphate, inositol 3,5-bisphosphate, inositol 3,4-bisphosphate, phosphatidylinositol 5-monophosphate, phosphatidylinositol 4-monophosphate and phosphatidylinositol 3-monophosphate (PubMed:16365287). Regulates lysosomal positioning by recruiting JIP4 to lysosomal membranes, thus inducing retrograde transport of lysosomes along microtubules (PubMed:29146937). Contributes to assembly of the V-ATPase complex in lipid rafts of the lysosomal membrane and to subsequent amino acid-dependent activation of mTORC1 (PubMed:29644770). May play a role in the regulation of cellular cholesterol metabolism (PubMed:25035345). (updated: June 5, 2019)
Protein identification was indicated in the following studies:
- 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.
- 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, is predicted to be membranous by TOPCONS.
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Biological Process
Cholesterol metabolic process
Lysosome localization
Phosphatidylinositol dephosphorylation
Phospholipid metabolic process
Positive regulation of TORC1 signaling
Proton-transporting V-type ATPase complex assembly
Regulation of signal transduction by p53 class mediator
Response to sterol depletion
The reference OMIM entry for this protein is 609865
Transmembrane protein 55b; tmem55b
Phosphatidylinositol 4,5-bisphosphate 4-phosphatase, type i
DESCRIPTION
TMEM55B catalyzes the degradation of phosphatidylinositol 4,5-bisphosphate (PtdIns-4,5-P2) by removing the 4-phosphate (Ungewickell et al., 2005).CLONING
By searching a database for genes encoding proteins similar to Burkholderia pseudomallei virulence factor BopB, a putative phosphatase, Ungewickell et al. (2005) identified TMEM55B. The deduced 257-amino acid protein contains a central Cx(5)R phosphatase catalytic motif and 2 transmembrane domains near its C terminus, a characteristic of lysosomal transmembrane proteins. RNA dot blot analysis detected expression in all tissues examined. Fluorescence-tagged TMEM55B localized with membrane markers of late endosomes or lysosomes. Endogenous HeLa cell TMEM55B showed a similar distribution.GENE FUNCTION
Ungewickell et al. (2005) assayed the phosphatase activity of TMEM55B synthesized in insect cells and found that it specifically catalyzed removal of the 4-phosphate from PtdIns-4,5-P2. It showed no activity toward other phosphatidylinositol substrates or inositol phosphates tested. Overexpression of TMEM55B in human embryonic kidney cells reduced the total cellular level of PtdIns-4,5-P2.MAPPING
By genomic sequence analysis, Ungewickell et al. (2005) mapped the TMEM55B gene to chromosome 14q11.2. ... More on the omim web site
June 7, 2019: Protein entry updated
Automatic update: Entry updated from uniprot information.
May 13, 2019: Protein entry updated
Automatic update: model status changed
Nov. 17, 2018: Protein entry updated
Automatic update: model status changed
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Oct. 27, 2017: Protein entry updated
Automatic update: model status changed
March 25, 2017: Additional information
No protein expression data in P. Mayeux work for TMEM55B
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 609865 was added.
Feb. 25, 2016: Protein entry updated
Automatic update: model status changed
Feb. 24, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed