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Sulfhydryl oxidation and Ca2+ release from sarcoplasmic reticulum
1Department of Physics, Portland State University, Oregon 97207.
Molecular and Cellular Biochemistry
|July 1, 1988
Summary
Heavy metals binding to or oxidation of critical sulfhydryl groups (SH) on skeletal muscle sarcoplasmic reticulum (SR) proteins trigger rapid calcium (Ca2+) release. This process also induces muscle contraction, suggesting redox control of Ca2+ channels.
Area of Science:
- Biochemistry
- Muscle Physiology
- Membrane Transport
Background:
- Sulfhydryl groups (SH) play crucial roles in protein function and regulation.
- Sarcoplasmic reticulum (SR) is the primary calcium storage site in muscle cells.
- Calcium (Ca2+) release from the SR is essential for muscle contraction.
Purpose of the Study:
- To investigate the role of a specific sulfhydryl group in the Ca2+-release protein of skeletal muscle SR.
- To determine how heavy metal binding and oxidation of this SH group affect Ca2+ transport and muscle function.
Main Methods:
- Utilized SR vesicles isolated from skeletal muscle.
- Studied the effects of heavy metal binding and sulfhydryl oxidation on Ca2+ release.
- Examined muscle contraction in skinned muscle fibers.
Main Results:
- Binding of heavy metals to the critical SH group induced rapid Ca2+ release from SR vesicles.
- Oxidation of the SH group to a disulfide also triggered rapid Ca2+ release and muscle contraction.
- Demonstrated a direct link between the redox state of the SH group and Ca2+ channel activity.
Conclusions:
- A critical sulfhydryl group on the SR Ca2+-release protein is essential for regulating Ca2+ transport.
- Heavy metal interactions and oxidative modification of this SH group lead to channel activation.
- Oxidation-reduction mechanisms may control the gating of the SR Ca2+-release channel, influencing muscle contraction.