Linked Life Data

8529260

Source:http://linkedlifedata.com/resource/pubmed/id/8529260

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1996-1-29
pubmed:abstractText
We previously found in single channel studies that ryanodine receptor (RyR) channel activity can be made insensitive to block by Mg2+ when terminal cisternae of sarcoplasmic reticulum, incorporated into planar bilayers, are treated with protein kinase A (PKA) or Ca2+/calmodulin dependent protein kinase type II (CamPK II), and then again made sensitive by treatment with protein phosphatases [Hain J. Nath S. Mayrleitner M. Fleischer S. Schindler H. (1994) Phosphorylation modulates the function of the calcium release channel of sarcoplasmic reticulum from skeletal muscle. Biophys. J., 67, 1823-1833]. In this study, modulation by protein kinases and phosphatases on net Ca2+ uptake by TC is presented. Phosphorylation of TC vesicles with PKA, CamPK II, or protein kinase C (PKC) reduced the calcium loading rate of TC vesicles 3-fold, 2.1-fold and 1.7-fold, respectively, measured in the presence of 1 mM MgCl2. There is no effect when AMP-PNP is substituted for ATP. Phosphorylation of the RyR was also measured by incorporation of [gamma-32P]-phosphate from ATP. A phosphorylation stoichiometry of 1.94 +/- 0.1 (32P/RyR) for PKA, 0.89 +/- 0.08 for CamPK II and 0.95 +/- 0.16 for PKC was obtained under these conditions. A study of the time dependence of phosphorylation with PKA and CamPK shows a direct correlation of reduction in calcium loading rate with increased phosphorylation of the ryanodine receptor. Treatment with protein phosphatase 1 enhanced the calcium loading rate again, after it was reduced by PKA phosphorylation. Investigation of the magnesium dependency shows that even at higher [Mg2+] (6 mM), PKA phosphorylated TC vesicles have a 2.3-fold reduced calcium loading rate indicating insensitivity to block by Mg2+.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0143-4160
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
197-206
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Phosphorylation with protein kinases modulates calcium loading of terminal cisternae of sarcoplasmic reticulum from skeletal muscle.
pubmed:affiliation
Department of Molecular Biology, Vanderbilt University, Nashville, Tennessee, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't