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[Calcium inhibition, a new mode for Ca2+ regulation]
1Department of Pharmacology, Gunma University School of Medicine, Japan.
Nihon Yakurigaku Zasshi. Folia Pharmacologica Japonica
|September 1, 1991
Summary
Calcium ions (Ca2+) can surprisingly inhibit cellular functions. This study reveals how elevated Ca2+ levels inhibit the actin-myosin-ATP interaction in Physarum polycephalum, a finding extended to plant and animal cells.
Area of Science:
- Cell Biology
- Biochemistry
Context:
- Intracellular calcium concentration ([Ca2+]i) is typically low in resting eukaryotic cells.
- Elevated [Ca2+]i from extracellular stimulation usually triggers excitatory cellular responses.
- A novel inhibitory role of Ca2+ on cellular function was observed in Physarum polycephalum.
Purpose:
- To describe the inhibitory mechanism of Ca2+ regulation on the actomyosin system in Physarum.
- To review the discovery and prevalence of this Ca2+-mediated inhibition in various cell types.
Summary:
- Micromolar concentrations of Ca2+ were found to inhibit the actin-myosin-ATP interaction in Physarum polycephalum.
- This inhibition is linked to reduced myosin phosphorylation, as Ca2+ also inhibits myosin kinase activity.
- This represents a unique instance where elevated [Ca2+]i leads to a transient abolition of a cellular process.
Impact:
- This research identified a previously unrecognized inhibitory role for calcium signaling in eukaryotic cells.
- The findings challenge the classical view of Ca2+ as solely an excitatory ion.
- This inhibitory mode of Ca2+ regulation has been subsequently observed in diverse plant and animal cell types, highlighting its broad biological significance.