Linked Life Data

9830046

Source:http://linkedlifedata.com/resource/pubmed/id/9830046

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
1999-1-8
pubmed:abstractText
Native large conductance, voltage-dependent, and Ca2+-sensitive K+ channels are activated by cGMP-dependent protein kinase. Two possible mechanisms of kinase action have been proposed: 1) direct phosphorylation of the channel and 2) indirect via PKG-dependent activation of a phosphatase. To scrutinize the first possibility, at the molecular level, we used the human pore-forming alpha-subunit of the Ca2+-sensitive K+ channel, Hslo, and the alpha-isoform of cGMP-dependent protein kinase I. In cell-attached patches of oocytes co-expressing the Hslo channel and the kinase, 8-Br-cGMP significantly increased the macroscopic currents. This increase in current was due to an increase in the channel voltage sensitivity by approximately 20 mV and was reversed by alkaline phosphatase treatment after patch excision. In inside-out patches, however, the effect of purified kinase was negative in 12 of 13 patches. In contrast, and consistent with the intact cell experiments, purified kinase applied to the cytoplasmic side of reconstituted channels increased their open probability. This stimulatory effect was absent when heat-denatured kinase was used. Biochemical experiments show that the purified kinase incorporates gamma-33P into the immunopurified Hslo band of approximately 125 kDa. Furthermore, in vivo phosphorylation largely attenuates this labeling in back-phosphorylation experiments. These results demonstrate that the alpha-subunit of large conductance Ca2+-sensitive K+ channels is substrate for G-Ialpha kinase in vivo and support direct phosphorylation as a mechanism for PKG-Ialpha-induced activation of maxi-K channels.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
32950-6
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
The large conductance, voltage-dependent, and calcium-sensitive K+ channel, Hslo, is a target of cGMP-dependent protein kinase phosphorylation in vivo.
pubmed:affiliation
Department of Anesthesiology, UCLA, Los Angeles, CA 90095-1778, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't