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  3. Chloroplast precursor protein preClpD overaccumulation triggers multilevel reprogramming of gene expression and a heat shock-like response

Chloroplast precursor protein preClpD overaccumulation triggers multilevel reprogramming of gene expression and a heat shock-like response

  • Nat Commun. 2025 Apr 22;16(1):3777. doi: 10.1038/s41467-025-59043-3.
Zheng-Hui Hong 1,  Liyu Zhu 1,  Lin-Lin Gao 1,  Zhe Zhu 2,  Tong Su 1,  Leonard Krall 2,  Xu-Na Wu 2,  Ralph Bock 3,  Guo-Zhang Wu 4
Affiliations

Affiliations

  • 1 Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
  • 2 School of Life Sciences, Yunnan University, Kunming, Yunnan Province, China.
  • 3 Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany.
  • 4 Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China. gzwu@sjtu.edu.cn.
PMID: 40263324 DOI: 10.1038/s41467-025-59043-3
Abstract

Thousands of nucleus-encoded chloroplast proteins are synthesized as precursors on cytosolic ribosomes and posttranslationally imported into chloroplasts. Cytosolic accumulation of unfolded chloroplast precursor proteins (e.g., under stress conditions) is hazardous to the cell. The global cellular responses and regulatory pathways involved in triggering appropriate responses are largely unknown. Here, by inducible and constitutive overexpression of ClpD-GFP to result in precursor protein overaccumulation, we present a comprehensive picture of multilevel reprogramming of gene expression in response to chloroplast precursor overaccumulation stress (cPOS), reveal a critical role of translational activation in the expression of cytosolic chaperones (heat-shock proteins, HSPs), and demonstrate that chloroplast-derived Reactive Oxygen Species act as retrograde signal for the transcriptional activation of small HSPs. Furthermore, we reveal an important role of the chaperone ClpB1/HOT1 in maintaining cellular proteostasis upon cPOS. Together, our observations uncover a cytosolic heat shock-like response to cPOS and provide insights into the underlying molecular mechanisms.

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