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Abstract Calcium ion transporting systems control cytosol Ca2+ levels ([Ca2+]cyt) and generate transient calcium (Ca2+) signatures that are key to environmental responses. Here, we report an impact of resting [Ca2+]cyt on plants from the functional study of calmodulin-regulated Ca2+ pumps or Ca2+-ATPases in Arabidopsis (Arabidopsis thaliana). The plasma membrane-localized pumps ACA8 (autoinhibited Ca2+-ATPase) and ACA10, as well as the vacuole-localized pumps ACA4 and ACA11, were critical in maintaining low resting [Ca2+]cyt and essential for plant survival under chilling and heat-stress conditions. Their loss-of-function mutants aca8 aca10 and aca4 aca11 had autoimmunity at normal temperatures, and this deregulated immune activation was enhanced by low temperature, leading to chilling lethality. Furthermore, these mutants showed an elevated resting [Ca2+]cyt, and a reduction of external Ca2+ lowered [Ca2+]cyt and repressed their autoimmunity and cold susceptibility. The aca8 aca10 and the aca4 aca11 mutants were also susceptible to heat, likely resulting from more closed stomata and higher leaf surface temperature than the wild type. These observations support a model in which the regulation of resting [Ca2+]cyt is critical to how plants regulate biotic and abiotic responses.
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Interference of pH buffer with Pb2+-peripheral domain interactions: obstacle or opportunity?
Abstract Pb2+ is a xenobiotic metal ion that competes for Ca2+-binding sites in proteins. Using the peripheral Ca2+-sensing domains of Syt1, we show that the chelating pH buffer Bis–Tris enables identification and functional characterization of high-affinity Pb2+ sites that are likely to be targeted by bioavailable Pb2+.
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- Award ID(s):
- 1905116
- PAR ID:
- 10528943
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Metallomics
- Volume:
- 12
- Issue:
- 2
- ISSN:
- 1756-5901
- Format(s):
- Medium: X Size: p. 164-172
- Size(s):
- p. 164-172
- Sponsoring Org:
- National Science Foundation
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