Ras-related protein Rab-22A (RAB22A)

The protein contains 194 amino acids for an estimated molecular weight of 21855 Da.

 

Plays a role in endocytosis and intracellular protein transport. Mediates trafficking of TF from early endosomes to recycling endosomes (PubMed:16537905). Required for NGF-mediated endocytosis of NTRK1, and subsequent neurite outgrowth (PubMed:21849477). Binds GTP and GDP and has low GTPase activity. Alternates between a GTP-bound active form and a GDP-bound inactive form (PubMed:16537905). (updated: Nov. 22, 2017)

Protein identification was indicated in the following studies:

  1. Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
  2. 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.
  3. 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.
  4. Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
  5. 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.

PublicationIdentification 1Uniprot mapping 2Not mapped /
Obsolete
TrEMBLSwiss-Prot
Goodman (2013)2289 (gene list)227853205992269
Lange (2014)123412347281224
Hegedus (2015)2638262202352387
Wilson (2016)165815281702911068
d'Alessandro (2017)18261817201815
Bryk (2017)20902060101081942
Chu (2018)18531804553621387

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.

No sequence conservation computed yet.

This protein is annotated as membranous in Gene Ontology, is annotated as membranous in UniProt.


Interpro domains
Total structural coverage: 100%
Model score: 0
No model available.

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The reference OMIM entry for this protein is 612966

Ras-associated protein rab22a; rab22a

DESCRIPTION

Small GTPases of the RAB family, such as RAB22A, are involved in the transport of macromolecules along endocytic and exocytic pathways (Magadan et al., 2006).

CLONING

By searching databases for RAS family members, followed by PCR, He et al. (2002) cloned RAB22A. The deduced 194-amino acid RAB22A protein contains 4 highly conserved GTPase motifs. Northern blot analysis detected a major transcript of about 2.4 kb in all tissues examined except testis. Highest expression was in lung, followed by heart, pancreas, and spleen. Using canine Rab22 to probe a Northern blot of mouse tissues, Olkkonen et al. (1993) detected widespread but variable expression of Rab22, with highest levels in brain and heart.

GENE FUNCTION

Kauppi et al. (2002) found that overexpression of canine Rab22a in hamster kidney cells caused formation of abnormally large early endosomal vacuoles. Expression of a GTPase-deficient Rab22a mutant caused accumulation of a fluid-phase marker and aspartylglucosaminidase (AGA; 208400) into abnormal vacuole-like structures that contained both early and late endosome markers. Overexpression of either wildtype or mutant Rab22a in HeLa cells caused redistribution of transferrin (TF; 190000)-positive endosomes to the leading edges of the cells, fragmentation of the Golgi complex, and reduced degradation of EGF (131530). Using immunohistochemical analysis, Weigert et al. (2004) showed that endogenous HeLa cell RAB22A localized on tubular endosomes and vesicles at the cell periphery, both of which contained major histocompatibility complex class I (MHCI; see 142800), but not transferrin. Knockdown of RAB22A in HeLa cells via small interfering RNA inhibited recycling of MHCI to the plasma membrane, but it only slightly affected recycling of transferrin. Internalization of MHCI and transferrin was not altered by knockdown of RAB22A. Weigert et al. (2004) concluded that RAB22A regulates the recycling of cargo proteins that enter the cell independently of clathrin (see CLTC; 118955). Magadan et al. (2006) found that overexpression of human RAB22A, but not canine Rab22a, in HeLa cells affected the distribution of transferrin receptor (TFRC; 190010) and altered transferrin recycling. Both wildtype RAB22A and GTPase-deficient RAB22A mutants affected the morphology of endosomes, inhibited transferrin recycling, and promoted redistribution of TFRC to large RAB22A-containing vesicles.

GENE STRUCTURE

He et al. (2002) determined that the RAB22A gene contains 9 exons and spans over 50.1 kb.

MAPPING

By radiation hybrid analysis, He et al. (2002) mapped the RAB22A gene to chromosome 20q13.3. ... More on the omim web site

Subscribe to this protein entry history

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

March 16, 2016: Protein entry updated
Automatic update: OMIM entry 612966 was added.