Ras GTPase-activating-like protein IQGAP2 (IQGAP2)

The protein contains 1575 amino acids for an estimated molecular weight of 180578 Da.

 

Binds to activated CDC42 and RAC1 but does not seem to stimulate their GTPase activity. Associates with calmodulin. (updated: March 4, 2015)

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. Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
  4. D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
  5. 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.

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.


Interpro domains
Total structural coverage: 26%
Model score: 0
No model available.

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VariantDescription
dbSNP:rs7722711
dbSNP:rs3822530
dbSNP:rs2431352
dbSNP:rs2909888
dbSNP:rs2455230
dbSNP:rs35366349
dbSNP:rs2431363
dbSNP:rs34950321
dbSNP:rs2287932
dbSNP:rs10454915
dbSNP:rs17681908
dbSNP:rs369078465
dbSNP:rs150409607

The reference OMIM entry for this protein is 605401

Iq motif-containing gtpase-activating protein 2; iqgap2

CLONING

GTPase-activating proteins (GAPs) accelerate the intrinsic GTPase activity of Ras proteins, resulting in conversion of these GTPases from their active GTP-bound form to the inactive GDP-bound form (see 139150). IQ motif-containing GAP1 (IQGAP1; 603379) was identified based on its homology to a RasGAP homolog from S. pombe, Sar1. Brill et al. (1996) identified IQGAP2 by screening a mouse brain cDNA library with a human IQGAP1 probe at low stringency. Human IQGAP2 cDNA clones were then isolated from liver cDNA libraries. The assembled full-length sequence encodes a 1,575-amino acid protein that is 62% identical to IQGAP1 and contains all domains previously identified in IQGAP1. These domains include a calponin homology (CH) domain, which is present in several actin-binding proteins; an IQGAP repeat domain containing 5 copies of a novel 50- to 55-amino acid repeat; a WW putative protein interaction domain; and 4 IQ motifs implicated in calmodulin (CALM1; 114180) binding. Like IQGAP1, IQGAP2 has several segments that have a high probability of forming coiled-coil structures similar to those in myosin heavy chains and intermediate filament proteins. IQGAP1 and IQGAP2 also share 25% amino acid identity with Sar1 over a 700-amino acid region. Northern blot analysis detected expression of an IQGAP2 transcript in mouse liver and of a shorter transcript in mouse testis. IQGAP2 expression was also detected in human hepatoblastoma and hepatocellular carcinoma cell lines, suggesting that IQGAP2 is expressed within hepatocytes in the liver.

GENE FUNCTION

By transfection and coprecipitation experiments, Brill et al. (1996) demonstrated that IQGAP2 bound CALM1 and that this binding required the IQ motifs of IQGAP2. IQGAP2 also bound the GTPases CDC42 (116952) and RAC1 (602048) through its C terminus, but it showed no evidence of GAP activity toward them.

MAPPING

By Southern blot analysis of somatic cell hybrid DNA, Brill et al. (1996) mapped the IQGAP2 gene to chromosome 5q11-q13. ... More on the omim web site

Subscribe to this protein entry history

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 605401 was added.

Jan. 28, 2016: Protein entry updated
Automatic update: model status changed

Jan. 25, 2016: Protein entry updated
Automatic update: model status changed