Linked Life Data

7677994

Source:http://linkedlifedata.com/resource/pubmed/id/7677994

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1993-1-28
pubmed:abstractText
Water channels provide the plasma membranes of red cells and renal proximal tubules with high permeability to water, thereby permitting water to move in the direction of an osmotic gradient. Molecular identification of CHIP28 protein as the membrane water channel was first accomplished by measurement of osmotic swelling of Xenopus oocytes injected with CHIP28 RNA (Preston, G.M., Carroll, T.P., Guggino, W.B., and Agre, P. (1992) Science 256, 385-387). Since water channels are pharmacologically inhibited by submillimolar concentrations of Hg2+, site-directed mutagenesis was undertaken to demonstrate which of the 4 cysteines (87, 102, 152, or 189) is the Hg(2+)-sensitive residue in the CHIP28 molecule. Each cysteine was individually replaced by serine, and oocytes expressing each of the four mutants exhibited osmotic water permeability (Pf) equivalent to wild-type CHIP28. After incubation in HgCl2, all were significantly inhibited, except C189S exists as a multisubunit complex in the native membrane; however, although oocytes injected with mixed CHIP28 and C189S RNAs exhibited Pf corresponding to the sum of their individual activities, exposure to Hg2+ only reduced the Pf to the level of the C189S mutant. Of the six substitutions at residue 189, only the serine and alanine mutants exhibited increased Pf and had glycosylation patterns resembling wild-type CHIP28 on immunoblots. These studies demonstrated: (i) CHIP28 water channel activity is retained despite substitution of individual cysteines with serine; (ii) cysteine 189 is the Hg(2+)-sensitive residue; (iii) the subunits of the CHIP28 complex are individually active water pores; (iv) residue 189 is critical to proper processing of the CHIP28 protein.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
268
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17-20
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
The mercury-sensitive residue at cysteine 189 in the CHIP28 water channel.
pubmed:affiliation
Department of Medicine and Cell Biology/Anatomy, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't