RHAG explained

Rh-associated glycoprotein (RHAG) is an ammonia transporter protein that in humans is encoded by the RHAG gene.^{[1] [2]} RHAG has also recently been designated CD241 (cluster of differentiation 241). Mutations in the RHAG gene can cause stomatocytosis.^[3]

Function

The Rh blood group antigens (MIM 111700) are associated with human erythrocyte membrane proteins of approximately 30 kD, the so-called Rh30 polypeptides. Heterogeneously glycosylated membrane proteins of 50 and 45 kD, the Rh50 glycoproteins, are coprecipitated with the Rh30 polypeptides on immunoprecipitation with anti-Rh-specific mono- and polyclonal antibodies. The Rh antigens appear to exist as a multisubunit complex of CD47 (MIM 601028), LW (MIM 111250), glycophorin B (MIM 111740), and play a critical role in the Rh50 glycoprotein [supplied by OMIM].

Interactions

RHAG has been shown to interact with ANK1.^[4]

See also

• Rh deficiency syndrome

Further reading

• Bakouh N, Benjelloun F, Cherif-Zahar B, Planelles G . The challenge of understanding ammonium homeostasis and the role of the Rh glycoproteins . Transfusion Clinique et Biologique . 13 . 1–2 . 139–46 . 2006 . 16564724 . 10.1016/j.tracli.2006.02.008 .
• Ripoche P, Goossens D, Devuyst O, Gane P, Colin Y, Verkman AS, Cartron JP . Role of RhAG and AQP1 in NH3 and CO2 gas transport in red cell ghosts: a stopped-flow analysis . Transfusion Clinique et Biologique . 13 . 1–2 . 117–22 . 2006 . 16574458 . 10.1016/j.tracli.2006.03.004 .
• Ridgwell K, Spurr NK, Laguda B, MacGeoch C, Avent ND, Tanner MJ . Isolation of cDNA clones for a 50 kDa glycoprotein of the human erythrocyte membrane associated with Rh (rhesus) blood-group antigen expression . The Biochemical Journal . 287 . 1. 223–8 . Oct 1992 . 1417776 . 1133147 . 10.1042/bj2870223. 287 .
• Avent ND, Ridgwell K, Mawby WJ, Tanner MJ, Anstee DJ, Kumpel B . Protein-sequence studies on Rh-related polypeptides suggest the presence of at least two groups of proteins which associate in the human red-cell membrane . The Biochemical Journal . 256 . 3 . 1043–6 . Dec 1988 . 3146980 . 1135522 . 10.1042/bj2561043.
• Cherif-Zahar B, Raynal V, Gane P, Mattei MG, Bailly P, Gibbs B, Colin Y, Cartron JP . Candidate gene acting as a suppressor of the RH locus in most cases of Rh-deficiency . Nature Genetics . 12 . 2 . 168–73 . Feb 1996 . 8563755 . 10.1038/ng0296-168 . 1999844 .
• Huang CH . The human Rh50 glycoprotein gene. Structural organization and associated splicing defect resulting in Rh(null) disease . The Journal of Biological Chemistry . 273 . 4 . 2207–13 . Jan 1998 . 9442063 . 10.1074/jbc.273.4.2207 . free .
• Hyland CA, Chérif-Zahar B, Cowley N, Raynal V, Parkes J, Saul A, Cartron JP . A novel single missense mutation identified along the RH50 gene in a composite heterozygous Rhnull blood donor of the regulator type . Blood . 91 . 4 . 1458–63 . Feb 1998 . 9454778 . 10.1182/blood.V91.4.1458. free .
• Iwamoto S, Omi T, Yamasaki M, Okuda H, Kawano M, Kajii E . Identification of 5' flanking sequence of RH50 gene and the core region for erythroid-specific expression . Biochemical and Biophysical Research Communications . 243 . 1 . 233–40 . Feb 1998 . 9473510 . 10.1006/bbrc.1997.8023 .
• Huang CH, Liu Z, Cheng G, Chen Y . Rh50 glycoprotein gene and rhnull disease: a silent splice donor is trans to a Gly279→Glu missense mutation in the conserved transmembrane segment . Blood . 92 . 5 . 1776–84 . Sep 1998 . 9716608 . 10.1182/blood.V92.5.1776.
• Chérif-Zahar B, Matassi G, Raynal V, Gane P, Delaunay J, Arrizabalaga B, Cartron JP . Rh-deficiency of the regulator type caused by splicing mutations in the human RH50 gene . Blood . 92 . 7 . 2535–40 . Oct 1998 . 9746795 . 10.1182/blood.V92.7.2535. free .
• Huang C, Cheng GJ, Reid ME, Chen Y . Rhmod syndrome: a family study of the translation-initiator mutation in the Rh50 glycoprotein gene . American Journal of Human Genetics . 64 . 1 . 108–17 . Jan 1999 . 9915949 . 1377708 . 10.1086/302215 .
• Huang CH, Cheng G, Liu Z, Chen Y, Reid ME, Halverson G, Okubo Y . Molecular basis for Rh(null) syndrome: identification of three new missense mutations in the Rh50 glycoprotein gene . American Journal of Hematology . 62 . 1 . 25–32 . Sep 1999 . 10467273 . 10.1002/(SICI)1096-8652(199909)62:1<25::AID-AJH5>3.0.CO;2-K . free .
• Iwamoto S, Suganuma H, Kamesaki T, Omi T, Okuda H, Kajii E . Cloning and characterization of erythroid-specific DNase I-hypersensitive site in human rhesus-associated glycoprotein gene . The Journal of Biological Chemistry . 275 . 35 . 27324–31 . Sep 2000 . 10862620 . 10.1074/jbc.M003297200 . free .
• Marini AM, Matassi G, Raynal V, André B, Cartron JP, Chérif-Zahar B . The human Rhesus-associated RhAG protein and a kidney homologue promote ammonium transport in yeast . Nature Genetics . 26 . 3 . 341–4 . Nov 2000 . 11062476 . 10.1038/81656 . 21313219 .
• Westhoff CM, Ferreri-Jacobia M, Mak DO, Foskett JK . Identification of the erythrocyte Rh blood group glycoprotein as a mammalian ammonium transporter . The Journal of Biological Chemistry . 277 . 15 . 12499–502 . Apr 2002 . 11861637 . 10.1074/jbc.C200060200 . free .
• Mouro-Chanteloup I, D'Ambrosio AM, Gane P, Le Van Kim C, Raynal V, Dhermy D, Cartron JP, Colin Y . Cell-surface expression of RhD blood group polypeptide is posttranscriptionally regulated by the RhAG glycoprotein . Blood . 100 . 3 . 1038–47 . Aug 2002 . 12130520 . 10.1182/blood.V100.3.1038. free .
• Chen BS, Xu ZX, Xu X, Cai Y, Han YL, Wang J, Xia SH, Hu H, Wei F, Wu M, Wang MR . RhCG is downregulated in oesophageal squamous cell carcinomas, but expressed in multiple squamous epithelia . European Journal of Cancer . 38 . 14 . 1927–36 . Sep 2002 . 12204676 . 10.1016/S0959-8049(02)00190-9 .
• Dahl KN, Westhoff CM, Discher DE . Fractional attachment of CD47 (IAP) to the erythrocyte cytoskeleton and visual colocalization with Rh protein complexes . Blood . 101 . 3 . 1194–9 . Feb 2003 . 12393442 . 10.1182/blood-2002-04-1187 . free .

External links

• • RhAG blood group system in the BGMUT blood group antigen gene mutation database

Notes and References

1. Matassi G, Chérif-Zahar B, Raynal V, Rouger P, Cartron JP . Organization of the human RH50A gene (RHAG) and evolution of base composition of the RH gene family . Genomics . 47 . 2 . 286–93 . Jan 1998 . 9479501 . 10.1006/geno.1997.5112 .
2. Web site: Entrez Gene: RHAG Rh-associated glycoprotein.
3. Stewart AK, Shmukler BE, Vandorpe DH, Rivera A, Heneghan JF, Li X, Hsu A, Karpatkin M, O'Neill AF, Bauer DE, Heeney MM, John K, Kuypers FA, Gallagher PG, Lux SE, Brugnara C, Westhoff CM, Alper SL . Loss-of-function and gain-of-function phenotypes of stomatocytosis mutant RhAG F65S . American Journal of Physiology. Cell Physiology . 301 . 6 . C1325-43 . Dec 2011 . 21849667 . 3233792 . 10.1152/ajpcell.00054.2011 .
4. Nicolas V, Le Van Kim C, Gane P, Birkenmeier C, Cartron JP, Colin Y, Mouro-Chanteloup I . Rh-RhAG/ankyrin-R, a new interaction site between the membrane bilayer and the red cell skeleton, is impaired by Rh(null)-associated mutation . The Journal of Biological Chemistry . 278 . 28 . 25526–33 . Jul 2003 . 12719424 . 10.1074/jbc.M302816200 . free .