Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1994-3-22
pubmed:abstractText
Reconstitution of highly purified aquaporin CHIP (channel-forming integral protein) into proteoliposomes was previously shown to confer high osmotic water permeability (Pf) to the membranes [Zeidel et al. (1992) Biochemistry 31, 7436-7440]. Here we report detailed ultrastructural, pharmacologic, and transport studies of human red cell CHIP in proteoliposomes. Freeze-fracture and transmission electron microscopy revealed a uniform distribution of CHIP which was incorporated into the membranes in both native and inverse orientations. Morphometric analysis of membranes reconstituted at three different concentrations of CHIP revealed that the intramembrane particles correspond to tetramers or possible higher order oligomers, and the Pf increased in direct proportion to the CHIP density. Proteolytic removal of the 4-kDa C-terminal cytoplasmic domain of CHIP did not alter the Pf or oligomerization in red cell membranes. CHIP exhibited a similar conductance for water when reconstituted into membranes of varied lipid compositions. The sensitivities of CHIP-mediated Pf to specific sulfhydryl reagents were identical to known sensitivities of red cell Pf, including a delayed response to p-(chloromercuri)benzenesulfonate. CHIP did not increase the permeability of the proteoliposome membranes to H+/OH- or NH3. These studies demonstrate that CHIP proteoliposomes exhibit all known characteristics of water channels in native red cells and therefore provide a defined system for biophysical analysis of transmembrane water movements.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1606-15
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Ultrastructure, pharmacologic inhibition, and transport selectivity of aquaporin channel-forming integral protein in proteoliposomes.
pubmed:affiliation
Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Presbyterian University Hospital, Pennsylvania 15261.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't