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Silver ions trigger Ca2+ release by interaction with the (Ca2+-Mg2+)-ATPase in reconstituted systems
The Journal of Biological Chemistry
|June 5, 1987
Summary
Silver ions (Ag+) trigger rapid calcium (Ca2+) release from skeletal muscle sarcoplasmic reticulum by interacting with the (Ca2+-Mg2+)-ATPase, suggesting this enzyme acts as a Ca2+ efflux pathway.
Area of Science:
- Muscle Physiology
- Biochemistry
- Ion Transport
Background:
- Sarcoplasmic reticulum vesicles are implicated in skeletal muscle calcium (Ca2+) regulation.
- Previous research suggested Ca2+ channels in these vesicles respond to sulfhydryl reagents like silver (Ag+).
Purpose of the Study:
- To investigate the role of the (Ca2+-Mg2+)-ATPase in Ca2+ efflux from sarcoplasmic reticulum.
- To determine if silver ions (Ag+) can induce Ca2+ release via the (Ca2+-Mg2+)-ATPase.
Main Methods:
- Purification of the (Ca2+-Mg2+)-ATPase from skeletal muscle sarcoplasmic reticulum.
- Reconstitution of purified ATPase into vesicles.
- Measurement of Ca2+ release from reconstituted vesicles in the presence of Ag+.
- Assay of ATPase activity.
Main Results:
- The purified (Ca2+-Mg2+)-ATPase alone in reconstituted vesicles facilitated Ca2+ efflux.
- Ag+ induced rapid Ca2+ release from these vesicles.
- Ag+ significantly inhibited the ATPase activity of the purified enzyme.
Conclusions:
- The (Ca2+-Mg2+)-ATPase can function as a pathway for Ca2+ efflux from sarcoplasmic reticulum.
- Silver ions (Ag+) can trigger rapid Ca2+ release by interacting with the (Ca2+-Mg2+)-ATPase, potentially by inhibiting its activity.