New insights into the Rh superfamily of genes and proteins in erythroid cells and nonerythroid tissues

Authors
Citation
Ch. Huang et Pz. Liu, New insights into the Rh superfamily of genes and proteins in erythroid cells and nonerythroid tissues, BL CELL M D, 27(1), 2001, pp. 90-101
Citations number
48
Categorie Soggetti
Cardiovascular & Hematology Research
Journal title
BLOOD CELLS MOLECULES AND DISEASES
ISSN journal
10799796 → ACNP
Volume
27
Issue
1
Year of publication
2001
Pages
90 - 101
Database
ISI
SICI code
1079-9796(200101)27:1<90:NIITRS>2.0.ZU;2-Q
Abstract
The past decade has seen extensive studies of the erythrocyte Rh30 polypept ides and Rh-associated glycoprotein, which specify the clinically important Rh blood group system. Here we consider recent advances on these and other Rh homologues in the context of gene organization, molecular evolution, ti ssue-specific expression, protein structure, and potential biological funct ions. The Rh family is now known to contain a large number of homologues th at form a unique branch in the eucarya life domain. The ancient origin and broad distribution imply central roles for the various Rh proteins in maint aining normal cellular and organismal homeostatic conditions. Rh homologues occur in the form of multiple chromosomal loci in mice and humans, but as single-copy genes in unicellular organisms (e.g., green alga and slime mold ). While primitive Rh genes vary largely in exon/intron design, the mammali an Rh homologues bear a similar genomic organization. Sequence comparisons have revealed the signatures and a consensus 12-transmembrane fold characte ristic of the Rh family. Phylogenetic analysis has placed all Rh homologues as a related cluster that intercepts ammonium transporter (Amt) clusters, indicating an intimate evolutionary and structural relationship between the Rh and Amt families. The biochemical identification and epithelial express ion of RhBG and RhCG orthologues in mammalian kidney, liver, skin, testis, and brain suggest that they serve as transporters likely participating in a mmonia homeostasis. Further inquires into the structure, function, biosynth esis, and interaction of Rh proteins will shed new light on ammonia homeost asis in a wide range of human physiological and pathological states. (C) 20 01 Academic Press.