CPK28-mediated Ca2+ signaling regulates STOP1 localization and accumulation to facilitate plant aluminum resistance
Abstract The transcription factor SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) functions as a crucial integrator of plant responses to various stresses, including aluminum (Al) stress. Its stability and accumulation are modulated by stress-specific post-translational mechanisms such as phosphorylatio...
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| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-06-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-60427-8 |
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| Summary: | Abstract The transcription factor SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) functions as a crucial integrator of plant responses to various stresses, including aluminum (Al) stress. Its stability and accumulation are modulated by stress-specific post-translational mechanisms such as phosphorylation and ubiquitination. However, the upstream signaling mechanisms governing these modifications remain poorly understood. Here, we reveal that Ca2+ signaling and Ca2+-dependent phosphorylation are essential for Al stress-responsive regulation of STOP1. Al exposure specifically induces rapid, spatio-temporally defined biphasic Ca2+ signals in Arabidopsis roots and concomitantly activates the Ca2+-dependent kinase CPK28. Al-activated CPK28 phosphorylates STOP1 at Ser163, a modification that promotes the nuclear localization of STOP1 and prevents its degradation by inhibiting its interaction with the F-box protein RAE1. This phosphorylation enhances STOP1 accumulation and Al resistance. Our findings identify Ser163 phosphorylation as a key molecular switch and establish a Ca2+-CPK28-STOP1 signaling axis critical for plant adaptation to Al stress. |
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| ISSN: | 2041-1723 |