Linked Life Data

1646298

Source:http://linkedlifedata.com/resource/pubmed/id/1646298

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1991-7-15
pubmed:abstractText
By incorporating plasma membrane vesicles into planar lipid bilayers, we previously characterized a family of four types of Ca(2+)-activated K+ channels from rat brain (Reinhart et al., 1989). Two of these are "large-conductance" or "maxi"-K+ channels, which differ in their gating kinetics and toxin sensitivity and are henceforth referred to as "type 1" and "type 2" channels. Here we show that the gating of these two channel types can be modulated by phosphorylation and dephosphorylation. The effects of cAMP-dependent protein kinase catalytic subunit (PK-A) on type 1 maxi-K+ channels are complex in that, while half of these channels are upregulated by the kinase, about one out of seven channels is downregulated. Thus, there may be several distinct channels within the type 1 category. Type 2 maxi-K+ channels are consistently downregulated by PK-A. The effects of PK-A on both channel types are reversed by the catalytic subunit of protein phosphatase 2A (PP-2A), but not by protein phosphatase 1 (PP-1). Furthermore, some of the type 1 maxi-K+ channels can be modulated by PP-2A, even without any prior PK-A treatment, indicating they are in a phosphorylated state when they are incorporated into the bilayer. The results demonstrate that (1) type 1 and type 2 maxi-K+ channels are substrates for PK-A; (2) phosphorylation can shift the open probability of channels in either direction, by a mechanism involving multiple phosphorylation sites; (3) phosphorylation alters the Ca2+/voltage sensitivity of these channels; and (4) dephosphorylation of type 1 and type 2 channels is catalyzed by specific phosphatases.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1627-35
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Modulation of calcium-activated potassium channels from rat brain by protein kinase A and phosphatase 2A.
pubmed:affiliation
Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.