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Blanco, Nicolas E.
Publications (6 of 6) Show all publications
Blanco, N. E., Liebsch, D., Guinea Diaz, M., Strand, Å. & Whelan, J. (2019). Dual and dynamic intracellular localization of Arabidopsis thaliana SnRK1.1. Journal of Experimental Botany, 70(8), 2325-2338
Open this publication in new window or tab >>Dual and dynamic intracellular localization of Arabidopsis thaliana SnRK1.1
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2019 (English)In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 70, no 8, p. 2325-2338Article in journal (Refereed) Published
Abstract [en]

Sucrose non-fermenting 1 (SNF1)-related protein kinase 1.1 (SnRK1.1; also known as KIN10 or SnRK1 alpha) has been identified as the catalytic subunit of the complex SnRK1, the Arabidopsis thaliana homologue of a central integrator of energy and stress signalling in eukaryotes dubbed AMPK/Snf1/SnRK1. A nuclear localization of SnRK1.1 has been previously described and is in line with its function as an integrator of energy and stress signals. Here, using two biological models (Nicotiana benthamiana and Arabidopsis thaliana), native regulatory sequences, different microscopy techniques, and manipulations of cellular energy status, it was found that SnRK1.1 is localized dynamically between the nucleus and endoplasmic reticulum (ER). This distribution was confirmed at a spatial and temporal level by co-localization studies with two different fluorescent ER markers, one of them being the SnRK1.1 phosphorylation target HMGR. The ER and nuclear localization displayed a dynamic behaviour in response to perturbations of the plastidic electron transport chain. These results suggest that an ER-associated SnRK1.1 fraction might be sensing the cellular energy status, being a point of crosstalk with other ER stress regulatory pathways.

Place, publisher, year, edition, pages
Oxford University Press, 2019
Keywords
Arabidopsis, chloroplast, dual localization, endoplasmic reticulum (ER), ER localization, energy atus, Nicotiana benthamiana, nuclear localization, retrograde signalling, SnRK1.1
National Category
Cell Biology
Identifiers
urn:nbn:se:umu:diva-163707 (URN)10.1093/jxb/erz023 (DOI)000483170800010 ()30753728 (PubMedID)
Available from: 2019-10-16 Created: 2019-10-16 Last updated: 2019-10-16Bibliographically approved
Blanco, N. E., Guinea-Diaz, M., Whelan, J. & Strand, Å. (2014). Interaction between plastid and mitochondrial retrograde signalling pathways during changes to plastid redox status. Philosophical Transactions of the Royal Society of London. Biological Sciences, 369(1640), Article ID 20130231.
Open this publication in new window or tab >>Interaction between plastid and mitochondrial retrograde signalling pathways during changes to plastid redox status
2014 (English)In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 369, no 1640, article id 20130231Article in journal (Refereed) Published
Abstract [en]

Mitochondria and chloroplasts depend upon each other; photosynthesis provides substrates for mitochondrial respiration and mitochondrial metabolism is essential for sustaining photosynthetic carbon assimilation. In addition, mitochondrial respiration protects photosynthesis against photoinhibition by dissipating excess redox equivalents from the chloroplasts. Genetic defects in mitochondrial function result in an excessive reduction and energization of the chloroplast. Thus, it is clear that the activities of mitochondria and plastids need to be coordinated, but the manner by which the organelles communicate to coordinate their activities is unknown. The regulator of alternative oxidase (rao1) mutant was isolated as a mutant unable to induce AOX1a expression in response to the inhibitor of the mitochondrial cytochrome c reductase (complex III), antimycin A. RAO1 encodes the nuclear localized cyclin-dependent kinase E1 (CDKE1). Interestingly, the rao1 mutant demonstrates a genome uncoupled phenotype also in response to redox changes in the photosynthetic electron transport chain. Thus, CDKE1 was shown to regulate both LIGHT HARVESTING COMPLEX B (LHCB) and ALTERNATIVE OXIDASE 1 (AOX1a) expression in response to retrograde signals. Our results suggest that CDKE1 is a central nuclear component integrating mitochondrial and plastid retrograde signals and plays a role in regulating energy metabolism during the response to stress.

Place, publisher, year, edition, pages
Royal Society Publishing, 2014
Keywords
redox, retrograde, chloroplast, mitochondria, kinase
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-87866 (URN)10.1098/rstb.2013.0231 (DOI)000332468400011 ()
Note

Special Issue: Changing the light environment: chloroplast signalling and response mechanisms

Available from: 2014-04-14 Created: 2014-04-14 Last updated: 2018-06-08Bibliographically approved
Ng, S., Giraud, E., Duncan, O., Law, S. R., Wang, Y., Xu, L., . . . Ivanova, A. (2013). Cyclin-dependent Kinase E1 (CDKE1) Provides a Cellular Switch in Plants between Growth and Stress Responses. Journal of Biological Chemistry, 288(5), 3449-3459
Open this publication in new window or tab >>Cyclin-dependent Kinase E1 (CDKE1) Provides a Cellular Switch in Plants between Growth and Stress Responses
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2013 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 288, no 5, p. 3449-3459Article in journal (Refereed) Published
Abstract [en]

Plants must deal effectively with unfavorable growth conditions that necessitate a coordinated response to integrate cellular signals with mitochondrial retrograde signals. A genetic screen was carried out to identify regulators of alternative oxidase (rao mutants), using AOX1a expression as a model system to study retrograde signaling in plants. Two independent rao1 mutant alleles identified CDKE1 as a central nuclear component integrating mitochondrial retrograde signals with energy signals under stress. CDKE1 is also necessary for responses to general cellular stresses, such as H2O2 and cold that act, at least in part, via anterograde pathways, and integrates signals from central energy/stress sensing kinase signal transduction pathways within the nucleus. Together, these results place CDKE1 as a central kinase integrating diverse cellular signals and shed light on a mechanism by which plants can effectively switch between growth and stress responses.

National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-66784 (URN)10.1074/jbc.M112.416727 (DOI)000314397900049 ()
Available from: 2013-03-12 Created: 2013-03-05 Last updated: 2018-06-08Bibliographically approved
Blanco, N. E., Ceccoli, R. D., Dalla Via, M. V., Voss, I., Segretin, M. E., Bravo-Almonacid, F. F., . . . Hanke, G. T. (2013). Expression of the Minor Isoform Pea Ferredoxin in Tobacco Alters Photosynthetic Electron Partitioning and Enhances Cyclic Electron Flow. Plant Physiology, 161(2), 866-879
Open this publication in new window or tab >>Expression of the Minor Isoform Pea Ferredoxin in Tobacco Alters Photosynthetic Electron Partitioning and Enhances Cyclic Electron Flow
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2013 (English)In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 161, no 2, p. 866-879Article in journal (Refereed) Published
Abstract [en]

Ferredoxins (Fds) are ferrosulfoproteins that function as low-potential electron carriers in plants. The Fd family is composed of several isoforms that share high sequence homology but differ in functional characteristics. In leaves, at least two isoforms conduct linear and cyclic photosynthetic electron transport around photosystem I, and mounting evidence suggests the existence of at least partial division of duties between these isoforms. To evaluate the contribution of different kinds of Fds to the control of electron fluxes along the photosynthetic electron transport chain, we overexpressed a minor pea (Pisum sativum) Fd isoform (PsFd1) in tobacco (Nicotiana tabacum) plants. The transplastomic OeFd1 plants exhibited variegated leaves and retarded growth and developmental rates. Photosynthetic studies of these plants indicated a reduction in carbon dioxide assimilation rates, photosystem II photochemistry, and linear electron flow. However, the plants showed an increase in nonphotochemical quenching, better control of excitation pressure at photosystem II, and no evidence of photoinhibition, implying a better dynamic regulation to remove excess energy from the photosynthetic electron transport chain. Finally, analysis of P700 redox status during illumination confirmed that the minor pea Fd isoform promotes enhanced cyclic flow around photosystem I. The two novel features of this work are: (1) that Fd levels achieved in transplastomic plants promote an alternative electron partitioning even under greenhouse light growth conditions, a situation that is exacerbated at higher light intensity measurements; and (2) that an alternative, minor Fd isoform has been overexpressed in plants, giving new evidence of labor division among Fd isoforms.

National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-66791 (URN)10.1104/pp.112.211078 (DOI)000314360100022 ()
Available from: 2013-03-11 Created: 2013-03-05 Last updated: 2018-06-08Bibliographically approved
Barajas-Lopez, J. d., Blanco, N. E. & Strand, Å. (2013). Plastid-to-nucleus communication, signals controlling the running of the plant cell. Biochimica et Biophysica Acta. Molecular Cell Research, 1833(2), 425-437
Open this publication in new window or tab >>Plastid-to-nucleus communication, signals controlling the running of the plant cell
2013 (English)In: Biochimica et Biophysica Acta. Molecular Cell Research, ISSN 0167-4889, E-ISSN 1879-2596, Vol. 1833, no 2, p. 425-437Article, review/survey (Refereed) Published
Abstract [en]

The presence of genes encoding organellar proteins in both the nucleus and the organelle necessitates tight coordination of expression by the different genomes, and this has led to the evolution of sophisticated intracellular signaling networks. Organelle-to-nucleus signaling, or retrograde control, coordinates the expression of nuclear genes encoding organellar proteins with the metabolic and developmental state of the organelle. Complex networks of retrograde signals orchestrate major changes in nuclear gene expression and coordinate cellular activities and assist the cell during plant development and stress responses. It has become clear that, even though the chloroplast depends on the nucleus for its function, plastid signals play important roles in an array of different cellular processes vital to the plant. Hence, the chloroplast exerts significant control over the running of the cell. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids. 

Keywords
Signaling, Retrograde, Plastids, Stress, Redox, Photosynthesis
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-66637 (URN)10.1016/j.bbamcr.2012.06.020 (DOI)000314002000020 ()
Available from: 2013-03-06 Created: 2013-02-26 Last updated: 2018-06-08Bibliographically approved
Kindgren, P., Kremnev, D., Blanco, N. E., Lopez, J. d., Fernandez, A. P., Tellgren-Roth, C., . . . Strand, Å. (2012). The plastid redox insensitive 2 mutant of Arabidopsis is impaired in PEP activity and high light-dependent plastid redox signalling to the nucleus. The Plant Journal, 70(2), 279-291
Open this publication in new window or tab >>The plastid redox insensitive 2 mutant of Arabidopsis is impaired in PEP activity and high light-dependent plastid redox signalling to the nucleus
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2012 (English)In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 70, no 2, p. 279-291Article in journal (Refereed) Published
Abstract [en]

The photosynthetic apparatus is composed of proteins encoded by genes from both the nuclear and the chloroplastic genomes. The activities of the nuclear and chloroplast genomes must therefore be closely coordinated through intracellular signalling. The plastids produce multiple retrograde signals at different times of their development, and in response to changes in the environment. These signals regulate the expression of nuclear-encoded photosynthesis genes to match the current status of the plastids. Using forward genetics we identified PLASTID REDOX INSENSITIVE 2 (PRIN2), a chloroplast component involved in redox-mediated retrograde signalling. The allelic mutants prin2-1 and prin2-2 demonstrated a misregulation of photosynthesis-associated nuclear gene expression in response to excess light, and an inhibition of photosynthetic electron transport. As a consequence of the misregulation of LHCB1.1 and LHCB2.4, the prin2 mutants displayed a high irradiance-sensitive phenotype with significant photoinactivation of photosystem II, indicated by a reduced variable to maximal fluorescence ratio (Fv/Fm). PRIN2 is localized to the nucleoids, and plastid transcriptome analyses demonstrated that PRIN2 is required for full expression of genes transcribed by the plastid-encoded RNA polymerase (PEP). Similarly to the prin2 mutants, the ys1 mutant with impaired PEP activity also demonstrated a misregulation of LHCB1.1 and LHCB2.4 expression in response to excess light, suggesting a direct role for PEP activity in redox-mediated retrograde signalling. Taken together, our results indicate that PRIN2 is part of the PEP machinery, and that the PEP complex responds to photosynthetic electron transport and generates a retrograde signal, enabling the plant to synchronize the expression of photosynthetic genes from both the nuclear and plastidic genomes.

Keywords
chloroplast, redox, signalling, PEP, photosynthesis, LHCB
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-55360 (URN)10.1111/j.1365-313X.2011.04865.x (DOI)000302300100008 ()
Note

In accordance with a correction published in The Plant Journal vol. 70, issue 2, page 366 (available at http://dx.doi.org/10.1111/j.1365-313X.2012.04978.x) Tatjana Kleine has been added to the list of authors for this paper.

Available from: 2012-05-31 Created: 2012-05-14 Last updated: 2018-06-08Bibliographically approved
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