The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons
During a plant’s life cycle, plastids undergo several modifications, from undifferentiated pro-plastids to either photosynthetically-active chloroplasts, ezioplasts, chromoplasts or storage organelles, such as amyloplasts, elaioplasts and proteinoplasts. Plastid proteome rearrangements and protein h...
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MDPI AG
2021-09-01
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| Series: | Genes |
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| Online Access: | https://www.mdpi.com/2073-4425/12/9/1387 |
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| author | Nicolaj Jeran Lisa Rotasperti Giorgia Frabetti Anna Calabritto Paolo Pesaresi Luca Tadini |
| author_facet | Nicolaj Jeran Lisa Rotasperti Giorgia Frabetti Anna Calabritto Paolo Pesaresi Luca Tadini |
| author_sort | Nicolaj Jeran |
| collection | DOAJ |
| description | During a plant’s life cycle, plastids undergo several modifications, from undifferentiated pro-plastids to either photosynthetically-active chloroplasts, ezioplasts, chromoplasts or storage organelles, such as amyloplasts, elaioplasts and proteinoplasts. Plastid proteome rearrangements and protein homeostasis, together with intracellular communication pathways, are key factors for correct plastid differentiation and functioning. When plastid development is affected, aberrant organelles are degraded and recycled in a process that involves plastid protein ubiquitination. In this study, we have analysed the Arabidopsis <i>gun1-102 ftsh5-3</i> double mutant, lacking both the plastid-located protein GUN1 (Genomes Uncoupled 1), involved in plastid-to-nucleus communication, and the chloroplast-located <i>FTSH</i>5 (Filamentous temperature-sensitive H5), a metalloprotease with a role in photosystem repair and chloroplast biogenesis. <i>gun1-102 ftsh5-3</i> seedlings show variegated cotyledons and true leaves that we attempted to suppress by introgressing second-site mutations in genes involved in: (i) plastid translation, (ii) plastid folding/import and (iii) cytosolic protein ubiquitination. Different phenotypic effects, ranging from seedling-lethality to partial or complete suppression of the variegated phenotype, were observed in the corresponding triple mutants. Our findings indicate that Plant U-Box 4 (PUB4) E3 ubiquitin ligase plays a major role in the target degradation of damaged chloroplasts and is the main contributor to the variegated phenotype observed in <i>gun1-102 ftsh5-3</i> seedlings. |
| first_indexed | 2024-03-10T07:38:31Z |
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| issn | 2073-4425 |
| language | English |
| last_indexed | 2024-03-10T07:38:31Z |
| publishDate | 2021-09-01 |
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| series | Genes |
| spelling | doaj.art-421b516733af410699d497ab625d76502023-11-22T13:14:17ZengMDPI AGGenes2073-44252021-09-01129138710.3390/genes12091387The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis CotyledonsNicolaj Jeran0Lisa Rotasperti1Giorgia Frabetti2Anna Calabritto3Paolo Pesaresi4Luca Tadini5Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, ItalyDuring a plant’s life cycle, plastids undergo several modifications, from undifferentiated pro-plastids to either photosynthetically-active chloroplasts, ezioplasts, chromoplasts or storage organelles, such as amyloplasts, elaioplasts and proteinoplasts. Plastid proteome rearrangements and protein homeostasis, together with intracellular communication pathways, are key factors for correct plastid differentiation and functioning. When plastid development is affected, aberrant organelles are degraded and recycled in a process that involves plastid protein ubiquitination. In this study, we have analysed the Arabidopsis <i>gun1-102 ftsh5-3</i> double mutant, lacking both the plastid-located protein GUN1 (Genomes Uncoupled 1), involved in plastid-to-nucleus communication, and the chloroplast-located <i>FTSH</i>5 (Filamentous temperature-sensitive H5), a metalloprotease with a role in photosystem repair and chloroplast biogenesis. <i>gun1-102 ftsh5-3</i> seedlings show variegated cotyledons and true leaves that we attempted to suppress by introgressing second-site mutations in genes involved in: (i) plastid translation, (ii) plastid folding/import and (iii) cytosolic protein ubiquitination. Different phenotypic effects, ranging from seedling-lethality to partial or complete suppression of the variegated phenotype, were observed in the corresponding triple mutants. Our findings indicate that Plant U-Box 4 (PUB4) E3 ubiquitin ligase plays a major role in the target degradation of damaged chloroplasts and is the main contributor to the variegated phenotype observed in <i>gun1-102 ftsh5-3</i> seedlings.https://www.mdpi.com/2073-4425/12/9/1387chloroplastubiquitinationvariegated phenotypeprotein homeostasis |
| spellingShingle | Nicolaj Jeran Lisa Rotasperti Giorgia Frabetti Anna Calabritto Paolo Pesaresi Luca Tadini The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons Genes chloroplast ubiquitination variegated phenotype protein homeostasis |
| title | The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons |
| title_full | The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons |
| title_fullStr | The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons |
| title_full_unstemmed | The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons |
| title_short | The PUB4 E3 Ubiquitin Ligase Is Responsible for the Variegated Phenotype Observed upon Alteration of Chloroplast Protein Homeostasis in Arabidopsis Cotyledons |
| title_sort | pub4 e3 ubiquitin ligase is responsible for the variegated phenotype observed upon alteration of chloroplast protein homeostasis in arabidopsis cotyledons |
| topic | chloroplast ubiquitination variegated phenotype protein homeostasis |
| url | https://www.mdpi.com/2073-4425/12/9/1387 |
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