THE EFFECTS OF CALCIUM, TEMPERATURE AND PHOSPHOLAMBAN PHOSPHORYLATION ON THE DYNAMICS OF THE CALCIUM-STIMULATED ATPASE OF CANINE CARDIAC SARCOPLASMIC-RETICULUM
THE EFFECTS OF CALCIUM, TEMPERATURE AND PHOSPHOLAMBAN PHOSPHORYLATION ON THE DYNAMICS OF THE CALCIUM-STIMULATED ATPASE OF CANINE CARDIAC SARCOPLASMIC-RETICULUM
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DOI：
10.1016/0005-2736(89)90323-4
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发表时间：
1989-04-28
期刊：
影响因子：
--
通讯作者：
CHAPMAN, D
中科院分区：
文献类型：
--
作者：
FOWLER, C;HUGGINS, JP;CHAPMAN, D
Highly purified sarcoplasmic reticulum (SR) has been prepared from dog hearts and has been incubated with the triplet probe erythrosinyl isothiocyanate to specifically label the Ca2+-stimulated ATPase (Ca2+-ATPase) of the SR. The rotational mobility of the Ca2+-ATPase has been studied in this erythrosin-labelled SR using time-resolved phosphorescence polarization. Qualitatively, the mobility of the cardiac Ca2+-ATPase resembles that of skeletal muscle SR Ca2+-ATPase. Addition of Ca2+ to SR affects the mobility of the Ca2+-ATPase in a way consistent with a segment of the ATPase altering its orientation relative to the plane of the membrane. Phosphorylation of phospholamban in cardiac SR by the purified catalytic subunit of cAMP-dependent protein kinase, which is known to increase the activity of the Ca2+-ATPase by deinhibition, also alters measured anisotropy. The changes observed are not compatible with dissociation of the Ca2+-ATPase from phospholamban after the latter is phosphorylated. The data are more consistent with phospholamban associating with the Ca2+-ATPase following phosphorylation, or more complex models in which only the hydrophilic domain of phospholamban binds with and dissociates from the Ca2+-ATPase.
