Probable Role of Allylisothiocyanate-Sensitive H
Keiko Mitsunaga1, Yukio Fujino2, Ikuo Yasumasu1
1Department of Biology, School of Education, Waseda University, 1-6-1, Nishiwaseda, Shinjuku-ku, Tokyo 160, Japan.
Development, Growth & Differentiation
|June 7, 2023
Summary
Allylisothiocyanate inhibits sea urchin spicule formation by blocking H+ , K+ -ATPase, a proton pump crucial for calcium carbonate deposition in mesenchyme cells.
Area of Science:
- Developmental Biology
- Cell Biology
- Biochemistry
Background:
- Sea urchin spicule formation is a critical process in embryonic development.
- Calcium carbonate deposition is essential for skeletal development.
Purpose of the Study:
- To investigate the role of proton pumps in sea urchin spicule formation.
- To identify the specific ATPase involved in mediating H+ release for CaCO3 deposition.
Main Methods:
- Inhibition studies using allylisothiocyanate and amiloride on spicule formation in embryos and cultured cells.
- Measurement of intravesicular acidification using [dimethylamine-14C]-aminopyrine.
- Assay of K+ -dependent ATPase activity in microsome fractions and isolated mesenchyme cells.
Main Results:
- Allylisothiocyanate, an inhibitor of H+ , K+ -ATPase, significantly inhibited spicule formation and intravesicular acidification.
- Amiloride showed minimal effect on spicule formation.
- H+ , K+ -ATPase activity was detected in mesenchyme cells and was sensitive to allylisothiocyanate.
- Valinomycin stimulated intravesicular acidification, suggesting increased K+ permeability post-prism stage.
Conclusions:
- H+ , K+ -ATPase likely mediates H+ release, accelerating CaCO3 deposition during sea urchin spicule formation.
- Increased K+ permeability after the prism stage may activate H+ release, facilitating calcification.
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