scholarly journals The challenge of determining the role of Rh glycoproteins in transport of NH3and NH4+

2014 ◽  
Vol 3 (3) ◽  
pp. 53-61 ◽  
Author(s):  
Nazih L. Nakhoul ◽  
L. Lee Hamm
Keyword(s):  
Rh Glycoproteins

scholarly journals Mechanisms of ammonia and ammonium transport by rhesus-associated glycoproteins

2015 ◽  
Vol 309 (11) ◽  
pp. C747-C758 ◽  
Author(s):  
Tolga Caner ◽  
Solange Abdulnour-Nakhoul ◽  
Karen Brown ◽  
M. Toriqul Islam ◽  
L. Lee Hamm ◽  
...  
Keyword(s):  
Xenopus Oocytes ◽  
Collecting Duct ◽  
Unique Property ◽  
Ammonium Transport ◽  
Surface Ph ◽  
Methyl Amine ◽  
Electrode Voltage ◽  
Rh Proteins ◽  
Rh Glycoproteins

In this study we characterized ammonia and ammonium (NH3/NH4+) transport by the rhesus-associated (Rh) glycoproteins RhAG, Rhbg, and Rhcg expressed in Xenopus oocytes. We used ion-selective microelectrodes and two-electrode voltage clamp to measure changes in intracellular pH, surface pH, and whole cell currents induced by NH3/NH4+ and methyl amine/ammonium (MA/MA+). These measurements allowed us to define signal-specific signatures to distinguish NH3 from NH4+ transport and to determine how transport of NH3 and NH4+ differs among RhAG, Rhbg, and Rhcg. Our data indicate that expression of Rh glycoproteins in oocytes generally enhanced NH3/NH4+ transport and that cellular changes induced by transport of MA/MA+ by Rh proteins were different from those induced by transport of NH3/NH4+. Our results support the following conclusions: 1) RhAG and Rhbg transport both the ionic NH4+ and neutral NH3 species; 2) transport of NH4+ is electrogenic; 3) like Rhbg, RhAG transport of NH4+ masks NH3 transport; and 4) Rhcg is likely to be a predominantly NH3 transporter, with no evidence of enhanced NH4+ transport by this transporter. The dual role of Rh proteins as NH3 and NH4+ transporters is a unique property and may be critical in understanding how transepithelial secretion of NH3/NH4+ occurs in the renal collecting duct.

scholarly journals Effect of collecting duct-specific deletion of both Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg) on renal response to metabolic acidosis

2014 ◽  
Vol 306 (4) ◽  
pp. F389-F400 ◽  
Author(s):  
Hyun-Wook Lee ◽  
Jill W. Verlander ◽  
Mary E. Handlogten ◽  
Ki-Hwan Han ◽  
I. David Weiner
Keyword(s):  
Metabolic Acidosis ◽  
Collecting Duct ◽  
Ammonia Excretion ◽  
Severe Metabolic Acidosis ◽  
Urine Ph ◽  
Renal Response ◽  
Rh Glycoproteins ◽  
Acid Loading ◽  
Specific Deletion

The Rhesus (Rh) glycoproteins, Rh B and Rh C Glycoprotein (Rhbg and Rhcg, respectively), are ammonia-specific transporters expressed in renal distal nephron and collecting duct sites that are necessary for normal rates of ammonia excretion. The purpose of the current studies was to determine the effect of their combined deletion from the renal collecting duct (CD-Rhbg/Rhcg-KO) on basal and acidosis-stimulated acid-base homeostasis. Under basal conditions, urine pH and ammonia excretion and serum HCO3− were similar in control (C) and CD-Rhbg/Rhcg-KO mice. After acid-loading for 7 days, CD-Rhbg/Rhcg-KO mice developed significantly more severe metabolic acidosis than did C mice. Acid loading increased ammonia excretion, but ammonia excretion increased more slowly in CD-Rhbg/Rhcg-KO and it was significantly less than in C mice on days 1–5. Urine pH was significantly more acidic in CD-Rhbg/Rhcg-KO mice on days 1, 3, and 5 of acid loading. Metabolic acidosis increased phosph enolpyruvate carboxykinase (PEPCK) and Na+/H+ exchanger NHE-3 and decreased glutamine synthetase (GS) expression in both genotypes, and these changes were significantly greater in CD-Rhbg/Rhcg-KO than in C mice. We conclude that 1) Rhbg and Rhcg are critically important in the renal response to metabolic acidosis; 2) the significantly greater changes in PEPCK, NHE-3, and GS expression in acid-loaded CD-Rhbg/Rhcg-KO compared with acid-loaded C mice cause the role of Rhbg and Rhcg to be underestimated quantitatively; and 3) in mice with intact Rhbg and Rhcg expression, metabolic acidosis does not induce maximal changes in PEPCK, NHE-3, and GS expression despite the presence of persistent metabolic acidosis.

The challenge of understanding ammonium homeostasis and the role of the Rh glycoproteins

2006 ◽  
Vol 13 (1-2) ◽  
pp. 139-146 ◽  
Author(s):  
N. Bakouh ◽  
F. Benjelloun ◽  
B. Cherif-Zahar ◽  
G. Planelles
Keyword(s):  
Rh Glycoproteins

oPnosDsA ib F le m lo o c le a c ti uolnesdoefdCurcoemdefrrosm ys t M em AI EaAntt ig e e st nss Understanding of the biochemical structures and molecular basis of Rh antigens is emerging rapidly. Absence of Rh antigens, as occurs in the RhnuN phenotype, compromises the integrity of red cells and cells from people with an RhnuN phenotype have been extensively studied. These studies contributed to the recognition of Rh polypeptides and some related glycoproteins [see 20,21,22]. Partial amino acid sequencing of the proteins in Bristol, Paris and Baltimore [23,24,25] led to recognition of involvement of two genes and isolation of cDNA by the Paris and Bristol workers [26,27] and cloning of the D gene [28]. One gene is responsible for the D polypeptide and another for the C and E series of antigens. However, although encoded by the same gene there is evidence that the C and E series of antigens are carried by different proteins. The molecular genetic basis of Rh antigens is discussed in another presentation. Immune precipitation using anti-D, -c, -E or R6A antibodies demonstrated the proteins which carried the Rh antigens. Two bands are co-precipitated by anti-D: one with an apparent Mr 30,000 called D30 polypeptide by the Bristol group and the other a diffuse band of 50-100 kD called the D50 polypeptide. Similar bands were observed when immune precipitation were done using anti-c, -E or R6A [see 20-22]. The D30 polypeptide was an unusual membrane protein because it was not glycosylated, the gene producing this protein and the other Rh protein were subsequently cloned. Assignment of the genes to chromosome 1p34-p36 confirmed that they are responsible for the Rh polymorphism [see 22]. The role of the Rh glycoproteins, the diffuse band of 50-1 OOkD, is not yet understood: the gene encoding the Rh glycoprotein when cloned was assigned to chromosome 6p21-qter [29].

1995 ◽  
pp. 192-192
Keyword(s):  
Molecular Basis ◽  
Molecular Genetic ◽  
The Other ◽  
Diffuse Band ◽  
Gene Encoding ◽  
Molecular Genetic Basis ◽  
Immune Precipitation ◽  
Rh Glycoproteins ◽  
Chromosome 1P34

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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