RGD Reference Report - Changes in subcellular distribution of the ammonia transporter, Rhcg, in response to chronic metabolic acidosis. - Rat Genome Database

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Changes in subcellular distribution of the ammonia transporter, Rhcg, in response to chronic metabolic acidosis.

Authors: Seshadri, RM  Klein, JD  Smith, T  Sands, JM  Handlogten, ME  Verlander, JW  Weiner, ID 
Citation: Seshadri RM, etal., Am J Physiol Renal Physiol. 2006 Jun;290(6):F1443-52. Epub 2006 Jan 24.
RGD ID: 8554189
Pubmed: PMID:16434569   (View Abstract at PubMed)
DOI: DOI:10.1152/ajprenal.00459.2005   (Journal Full-text)

The primary mechanism by which the kidneys mediate net acid excretion is through ammonia metabolism. In the current study, we examined whether chronic metabolic acidosis, which increases ammonia metabolism, alters the cell-specific and/or the subcellular expression of the ammonia transporter family member, Rhcg, in the outer medullary collecting duct in the inner stripe (OMCDi). Chronic metabolic acidosis was induced in normal SD rats by HCl ingestion for 7 days; controls were pair-fed. The subcellular distribution of Rhcg was determined using immunogold electron microscopy and morphometric analyses. In intercalated cells, acidosis increased total Rhcg, apical plasma membrane Rhcg, and the proportion of total cellular Rhcg in the apical plasma membrane. Intracellular Rhcg decreased significantly, and basolateral Rhcg was unchanged. Because apical plasma membrane length increased in parallel with apical Rhcg immunolabel, apical plasma membrane Rhcg density was unchanged. In principal cells, acidosis increased total Rhcg, apical plasma membrane Rhcg, and the proportion of total cellular Rhcg in the apical plasma membrane while decreasing the intracellular proportion. In contrast to the intercalated cell, chronic metabolic acidosis did not significantly alter apical boundary length; accordingly, apical plasma membrane Rhcg density increased. In addition, basolateral Rhcg immunolabel increased in response to chronic metabolic acidosis. These results indicate that in the rat OMCDi 1) chronic metabolic acidosis increases apical plasma membrane Rhcg in both the intercalated cell and principal cell where it may contribute to enhanced apical ammonia secretion; 2) increased apical plasma membrane Rhcg results from both increased total protein and changes in the subcellular distribution of Rhcg; 3) the mechanism of Rhcg subcellular redistribution differs in intercalated and principal cells; and 4) Rhcg may contribute to regulated basolateral ammonia transport in the principal cell.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
ammonium transmembrane transport involved_inIDA 8554189PMID:16434569UniProt 

Cellular Component
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
apical plasma membrane located_inIDA 8554189PMID:16434569UniProt 
basolateral plasma membrane located_inIDA 8554189PMID:16434569UniProt 
cytoplasmic vesicle located_inIDA 8554189PMID:16434569UniProt 

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
ammonium transmembrane transporter activity enablesIDA 8554189PMID:16434569UniProt 

Objects Annotated

Genes (Rattus norvegicus)
Rhcg  (Rh family, C glycoprotein)


Additional Information