Linked Life Data

11297561

Source:http://linkedlifedata.com/resource/pubmed/id/11297561

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2001-6-11
pubmed:abstractText
Mutations in the aquaporin-2 (AQP2) water channel cause the hereditary renal disease nephrogenic diabetes insipidus (NDI). The missense mutation AQP2-T126M causes human recessive NDI by retention at the endoplasmic reticulum (ER) of renal epithelial cells. To determine whether the ER retention of AQP2-T126M is due to relative immobilization in the ER, we measured by fluorescence recovery after photobleaching the intramembrane mobility of green fluorescent protein (GFP) chimeras containing human wild-type and mutant AQP2. In transfected LLC-PK1 renal epithelial cells, GFP-labeled AQP2-T126M was localized to the ER, and wild-type AQP2 to endosomes and the plasma membrane; both were localized to the ER after brefeldin A treatment. Photobleaching with image detection indicated that the GFP-AQP2 chimeras were freely mobile throughout the ER. Quantitative spot photobleaching revealed a diffusion-dependent irreversible process whose recovery depended on spot size and was abolished by paraformaldehyde fixation. In addition, a novel slow reversible fluorescence recovery (t(12) approximately 2 s) was characterized whose recovery was independent of spot size and not affected by fixation. AQP2 translational diffusion in the ER was not slowed by the T126M mutation; diffusion coefficients were (in cm(2)/s x 10(-)10) 2.6 +/- 0.5 (wild-type) and 3.0 +/- 0.4 (T126M). Much faster diffusion was found for a lipid probe (diOC(4)(3), 2.7 x 10(-)8 cm(2)/s) in the ER membrane and for unconjugated GFP in the aqueous ER lumen (6 x 10(-)8 cm(2)/s). ER diffusion of GFP-T126M was not significantly affected by up-regulation of molecular chaperones, cAMP activation, or actin filament disruption. ATP depletion by 2-deoxyglucose and azide resulted in comparable slowing/immobilization of wild-type and T126M AQP2. These results indicate that the ER retention of AQP2-T126M does not result from restricted or slowed mobility and suggest that the majority of AQP2-T126M is not aggregated or bound to slowly moving membrane proteins.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21331-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:11297561-Animals, pubmed-meshheading:11297561-Aquaporin 2, pubmed-meshheading:11297561-Aquaporin 6, pubmed-meshheading:11297561-Aquaporins, pubmed-meshheading:11297561-Brefeldin A, pubmed-meshheading:11297561-Cell Line, pubmed-meshheading:11297561-Cell Membrane, pubmed-meshheading:11297561-Diabetes Insipidus, Nephrogenic, pubmed-meshheading:11297561-Diffusion, pubmed-meshheading:11297561-Endoplasmic Reticulum, pubmed-meshheading:11297561-Humans, pubmed-meshheading:11297561-Kidney, pubmed-meshheading:11297561-Kinetics, pubmed-meshheading:11297561-Models, Molecular, pubmed-meshheading:11297561-Mutation, Missense, pubmed-meshheading:11297561-Protein Structure, Secondary, pubmed-meshheading:11297561-Protein Synthesis Inhibitors, pubmed-meshheading:11297561-Recombinant Fusion Proteins, pubmed-meshheading:11297561-Transfection, pubmed-meshheading:11297561-Urothelium
pubmed:year
2001
pubmed:articleTitle
Diffusion in the endoplasmic reticulum of an aquaporin-2 mutant causing human nephrogenic diabetes insipidus.
pubmed:affiliation
Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, California 94143-0521.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't