RhCG is the major putative ammonia transporter expressed in the human kidney, and RhBG is not expressed at detectable levels.

Rhesus glycoprotein homologs RhAG, RhBG, and RhCG comprise a recently identified branch of the Mep/Amt ammonia transporter family. Animal studies have shown that RhBG and RhCG are present in the kidney distal tubules. Studies in mouse and rat tissue suggest a basolateral localization for RhBG in cells of the distal tubules including the alpha-intercalated cells (alpha-IC), but no localization of RhBG has been reported in human tissue.

Human kidney anion exchanger 1 localisation in MDCK cells is controlled by the phosphorylation status of two critical tyrosines.

An important question in renal physiology is how the alpha-intercalated cells of the kidney regulate the distribution of the basolateral kidney anion exchanger 1 (kAE1) according to systemic acid-base status. Previous work using a MDCKI model system demonstrated that kAE1 basolateral targeting requires an N-terminal determinant and a critical C-terminal tyrosine (Y904). Here, we show that the N-terminal determinant is residue Y359, because a Y359A substitution mutant was mistargeted to the apical membrane.

Identification of abundant proteins and potential allergens in Culicoides nubeculosus salivary glands.

IgE-mediated type 1 hypersensitivity reactions to the bites of insects are a common cause of skin disease in horses. Insect bite hypersensitivity (IBH) is most frequently associated with bites of Culicoides spp. and occurs in all parts of the world where horses and Culicoides coexist.

Analysis of tryptic digests indicates regions of GvpC that bind to gas vesicles of Anabaena flos-aquae.

The gas vesicles of the cyanobacterium Anabaena flos-aquae contain two main proteins: GvpA, which forms the ribs of the hollow cylindrical shell, and GvpC, which occurs on the outer surface. Analysis by MALDI-TOF MS shows that after incubating Anabaena gas vesicles in trypsin, GvpA was cleaved only at sites near the N-terminus, whereas GvpC was cleaved at most of its potential tryptic sites. Many of the resulting tryptic peptides from GvpC remained attached to the underlying GvpA shell: the pattern of attachment indicated that there are binding sites to GvpA at both ends of the 33-residue repeats (33RRs) in GvpC, although one of the tryptic peptides within the 33RR did not remain attached.

Absence of CD47 in protein 4.2-deficient hereditary spherocytosis in man: an interaction between the Rh complex and the band 3 complex.

We present data on a patient of South Asian origin with recessive hereditary spherocytosis (HS) due to absence of protein 4.2 [4.2 (-) HS].

The low-frequency MNS blood group antigens Ny(a) (MNS18) and Os(a) (MNS38) are associated with GPA amino acid substitutions.

Background: Antigens of the MNS blood group system are located on two sialoglycoproteins, GPA and GPB, encoded by GYPA and GYPB. The molecular backgrounds of the low-frequency antigens Ny(a) and Os(a) are not known.

Study Design And Methods: Immunoblotting and a monoclonal antibody-specific immobilization of erythrocyte antigens (MAIEA) assay were used to analyze Os(a).

Complementation studies with Co-expressed fragments of the human red cell anion transporter (Band 3; AE1). The role of some exofacial loops in anion transport.

We constructed cDNA clones encoding fragments of band 3 in which the membrane domain was truncated from either the N or the C terminus within each of the first four exofacial loops. The truncations containing the C terminus of the protein were fused with the cleavable N-terminal signal sequence of glycophorin A to facilitate the correct orientation of the most N-terminal band 3 membrane span. Cleavage of the glycophorin A signal sequence was observed, except when the truncation was in the first exofacial loop where the signal peptidase cleavage site was probably too close to the membrane.

The Oka blood group antigen is a marker for the M6 leukocyte activation antigen, the human homolog of OX-47 antigen, basigin and neurothelin, an immunoglobulin superfamily molecule that is widely expressed in human cells and tissues.

The high-frequency blood group antigen Ok(a) is carried on a red cell membrane glycoprotein (gp) of 35-69 kDa that is widely distributed on malignant cells of different origins. Immunostaining of hemopoietic cells and a range of normal human tissues demonstrated a wide distribution of the Ok(a) gp that appears to be nonlineage-restricted, although certain tissues show differentiation-related expression. Ok(a) gp was purified from red cell membranes by immunoaffinity chromatography using mAb A103 and amino acid sequence analysis was performed.

Immunochemical analysis of the human erythrocyte Rh polypeptides.

We have used rabbit polyclonal antisera raised against synthetic peptides complementary to different domains of the Rh polypeptides and Rh glycoprotein to examine the topography and organization of these proteins in the human erythrocyte membrane. Previously unrecognized exofacial protease sites have been identified on Rh CcEe, D proteins, and Rh glycoprotein. The Rh D protein has two specific bromelain cleavage sites located within the first and sixth predicted external domains, with the site of cleavage localized in the sixth domain to lie between residues 353 and 354.

The Lutheran blood group glycoprotein, another member of the immunoglobulin superfamily, is widely expressed in human tissues and is developmentally regulated in human liver.

Glycoproteins expressing the Lutheran blood group antigens were isolated from human erythrocyte membranes and from human fetal liver. Amino acid sequence analyses allowed the design of redundant oligonucleotides that were used to generate a 459-bp, sequence-specific probe by PCR. A cDNA clone of 2400 bp was isolated from a human placental lambda gt 11 library and sequenced, and the deduced amino acid sequence was studied.

Reactivity with erythroid and non-erythroid tissues of a murine monoclonal antibody to a synthetic peptide having amino acid sequence common to cytoplasmic domain of human glycophorins C and D.

Three synthetic peptides encompassing the entire cytoplasmic polypeptide sequence (amino acid residues 82-128) of glycophorin C (GPC) and glycophorin D (GPD) were used to immunize mice for the production of monoclonal antibodies (MoAbs). Only the synthetic peptide (GPC-peptide-1) corresponding to C-terminal residues 112-128 elicited a MoAb (named BGRL-100) which could react with native and denatured GPC and GPD. We characterized BGRL-100 by inhibition using GPC-peptide 1 and red cell sialoglycoproteins.

Isolation and characterization of CD47 glycoprotein: a multispanning membrane protein which is the same as integrin-associated protein (IAP) and the ovarian tumour marker OA3.

The CD47 glycoprotein was isolated from human erythrocytes by immunoprecipitation using monoclonal antibody (mAb) BRIC-125. Enzymic deglycosylation of the protein showed it contained N-linked oligosaccharides, and trypsin proteolysis of the protein in situ in the erythrocyte membrane cleaved it into two portions, one of which was glycosylated. Both the intact protein and the glycosylated fragment had blocked N-termini.

Duplication of exon 3 in the glycophorin C gene gives rise to the Lsa blood group antigen.

Background: The Gerbich-related Lsa blood group antigen (Ge6) resides on the higher-molecular-weight forms of glycophorin C (GPC) and glycophorin D (GPD). Southern blot analysis has previously revealed an additional GPC exon 3 insert in the genomic DNA from an Ls(a+) individual.

Study Design And Methods: To confirm the duplication of exon 3 in the GPC mRNA, total RNA prepared from the Epstein-Barr virus-transformed lymphocytes of an Ls(a+) individual was used in the synthesis of first-strand cDNA.

Localization of the protein 4.1-binding site on human erythrocyte glycophorins C and D.

The flexibility of the human erythrocyte membrane is mediated by an underlying network of skeletal proteins which interact with the membrane through ankyrin and protein 4.1. The nature of the membrane attachment site(s) for protein 4.

Topology and organization of human Rh (rhesus) blood group-related polypeptides.

The Rh blood group antigens are associated with nonglycosylated human erythrocyte membrane proteins of molecular mass 30 kDa (the Rh30 polypeptides) and a glycoprotein of 40-100 kDa (the Rh glycoprotein). We have studied the topology of this family of proteins in the erythrocyte membrane. We confirmed the predicted cytosolic localization of the C and N termini of the Rh protein family.

Studies on the glycoprotein associated with Rh (rhesus) blood group antigen expression in the human red blood cell membrane.

The blood group Rh antigens are associated with non-glycosylated 30-kDa erythrocyte membrane proteins (the Rh30 polypeptides) and the Rh glycoprotein. We used antipeptide antibodies to study the Rh glycoprotein in human erythrocyte membranes. The Rh glycoprotein was present in Rhnull U+ve cells.

Localization of the C termini of the Rh (rhesus) polypeptides to the cytoplasmic face of the human erythrocyte membrane.

We have raised a rabbit antiserum to a synthetic peptide corresponding to the C terminus (residues 400-416) of the Rh30A polypeptide. The rabbit antiserum reacted with the Rh30B (D30) polypeptide in addition to the Rh30A (C/c and/or E/e) polypeptide(s), indicating that these proteins share homology at their C termini. The antiserum did not react with erythrocyte membranes from an individual with Rh(null) syndrome.

The abundance and organization of polypeptides associated with antigens of the Rh blood group system.

Twelve murine monoclonal antibodies, which react with human red cells of common Rh phenotype but give weak or negative reactions with Rh null erythrocytes, were used in quantitative binding assays and competitive binding assays to investigate the abundance and organization of polypeptides involved in the expression of antigens of the Rh blood group system. Antibodies of the R6A-type (R6A, BRIC-69, BRIC-207) and the 2D10-type (MB-2D10, LA18.18, LA23.

The membrane domain of the human erythrocyte anion transport protein. Epitope mapping of a monoclonal antibody defines the location of a cytoplasmic loop near the C-terminus of the protein.

We have used synthetic peptides to study the location of the amino acid sequences in the human erythrocyte anion transport protein (band 3) which are recognized by four murine monoclonal antibodies, BRIC 130, 132, 154 and 155. These antibodies are known to react with epitopes in the protein which are on the cytoplasmic side of the membrane. The results suggest that the amino acid residues important for the reaction of BRIC 130 and BRIC 154/155 are located within amino acids 899-908 and 895-901 respectively in the cytoplasmic tail of the protein.

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 Rh D blood-group antigen forms part of a complex, involving several other polypeptides, that is deficient in the red cells of individuals who lack all the antigens of the Rh blood-group system (Rhnull red cells). These include components recognized by anti-(Rh D) antibodies and the murine monoclonal antibodies R6A and BRIC 125. We have carried out protein-sequence studies on the components immunoprecipitated by these antibodies.

Incomplete glycosylation of erythrocyte membrane proteins in congenital dyserythropoietic anaemia type II (CDA II).

The alterations in the erythrocyte membrane proteins of individuals with congenital dyserythropoietic anaemia (CDA II) were studied. Alterations were observed in both the erythrocyte sialoglycoproteins and erythrocyte anion transport protein (Band 3). There was a decrease in the apparent molecular weight of the major sialoglycoprotein alpha (glycophorin A) as well as a general reduction in the intensity of staining of all the sialoglycoproteins by the PAS stain.

Characterization and partial sequence of di-iodosulphophenyl isothiocyanate-binding peptide from human erythrocyte anion-transport protein.

We investigated the presumed anion-binding domain of the anion-transport protein from human erythrocyte membranes, using 2,6-di-iodo-4-sulphophenyl isothiocyanate, an inhibitor of anion transport. The 125I-labelled reagent binds covalently to the protein with a half-maximal inhibitory concentration of 86 microM. Treatment of unsealed erythrocyte 'ghosts' with chymotrypsin yielded a membrane-bound fragment (mol.

Immunochemical evidence for hybrid sialoglycoproteins of human erythrocytes.

The two major sialoglycoproteins of the human erythrocyte membrane (alpha and delta, glycophorins A and B) have identical amino acid sequences for the first 26 residues from the amino terminus, except that alpha expresses M or N blood group antigen activity whereas deta carries only blood group N activity. In addition, the asparagine at position 26 on alpha carries an oligosaccharide chain which is absent from the same position on delta. The two sialoglycoproteins differ in their remaining amino acid sequence and delta expresses blood group Ss activity.

Studies on the blood of an MiV homozygote.

An individual, whose parents are third cousins, has been shown to be homozygous for the rare Mi.V. condition.