Megadalton Complexes in the Chloroplast Stroma of Arabidopsis thaliana Characterized by Size Exclusion Chromatography, Mass Spectrometry, and Hierarchical Clustering

Olinares, Paul Dominic B.; Ponnala, Lalit; Wijk, Klaas J. van

doi:10.1074/mcp.m000038-mcp201

Cited by 178 publications

(201 citation statements)

References 164 publications

(190 reference statements)

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“…ii) A fusion of GFP to the first 100 N-terminal amino acids of ISE2 that contains the predicted chloroplast transit peptide localizes to chloroplasts (20). iii) Proteomic analyses consistently identified ISE2 in chloroplast extracts (21,22). Further, ISE2 fractionates with high-molecular-weight complexes (1-3 MDa) of the chloroplast stroma (22), consistent with our observation of its localization to relatively large foci.…”

supporting

confidence: 73%

Organelle–nucleus cross-talk regulates plant intercellular communication via plasmodesmata

Burch‐Smith¹,

Brunkard²,

Choi

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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We use Arabidopsis thaliana embryogenesis as a model system for studying intercellular transport via plasmodesmata (PD). A forward genetic screen for altered PD transport identified increased size exclusion limit (ise) 1 and ise2 mutants with increased intercellular transport of fluorescent 10-kDa tracers. Both ise1 and ise2 exhibit increased formation of twinned and branched PD. ISE1 encodes a mitochondrial DEAD-box RNA helicase, whereas ISE2 encodes a DEVH-type RNA helicase. Here, we show that ISE2 foci are localized to the chloroplast stroma. Surprisingly, plastid development is defective in both ise1 and ise2 mutant embryos. In an effort to understand how RNA helicases that localize to different organelles have similar impacts on plastid and PD development/function, we performed whole-genome expression analyses. The most significantly affected class of transcripts in both mutants encode products that target to and enable plastid function. These results reinforce the importance of plastid-mitochondria-nucleus cross-talk, add PD as a critical player in the plant cell communication network, and thereby illuminate a previously undescribed signaling pathway dubbed organelle-nucleus-plasmodesmata signaling. Several genes with roles in cell wall synthesis and modification are also differentially expressed in both mutants, providing new targets for investigating PD development and function.

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supporting

confidence: 73%

Organelle–nucleus cross-talk regulates plant intercellular communication via plasmodesmata

Burch‐Smith¹,

Brunkard²,

Choi

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…When mentioned in previous reports, these proteins were labeled as BCCP-like due to their sequence similarity to BCCP. The BADCs were observed to coelute with Arabidopsis hetACCase during size-exclusion chromatography (Olinares et al, 2010) and were also detected in pull-down experiments with the 2-oxoglutarate binding protein PII along with both BCCP isoforms (Feria Bourrellier et al, 2010). In both cases, a direct interaction between ACCase catalytic subunits and the BADCs was not established, and a functional role was neither determined nor proposed.…”

Section: Discussionmentioning

confidence: 99%

“…Results shown are representative of three biological replicates, i.e., three separate transformation events. many other characteristics with the two BCCP isoforms from Arabidopsis: (1) these proteins contain a canonical plastid target peptide and are plastid localized based upon co-IP results here using purified chloroplasts and proteomic analysis of purified chloroplasts (Olinares et al, 2010); (2) the BADC isoforms share 24 to 29% amino acid sequence identity with the BCCP isoforms ( Figure 5A); (3) structural predictions of the BADC and BCCP proteins show similar b-sheet secondary structure with a characteristic "thumb motif" as previously observed for the E. coli BCCP ) ( Figure 5B). Despite these similarities, BADCs lack the canonical biotinylation motif ( Figure 5C).…”

Section: Badcs Resemble Bccps But Are Not Biotinylatedmentioning

confidence: 99%

“…Other properties of the plant hetACCase suggest additional, noncatalytic components may be involved in its function or regulation: (1) the observed size of the plant hetACCase complex is larger than the calculated mass of the known subunits (Reverdatto et al, 1999;Olinares et al, 2010); (2) the a-and b-CT subunits contain large domains of 200 to 300 residues that are not required for catalytic activity, are not present in prokaryotic homologs, and have no known function (Kozaki et al, 2001;Cronan and Waldrop, 2002); (3) the CT subcomplex associates with the plastid inner envelope through an unknown, non-ionic interaction (Thelen and Ohlrogge, 2002b); and 4) the a-CT subunit is phosphorylated on multiple sites but its functional role is unclear (Nakagami et al, 2010;Meyer et al, 2012). Collectively, these observations suggest that hetACCase may possess additional factors that facilitate the various forms of regulation.…”

Section: Introductionmentioning

confidence: 99%

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A Family of Negative Regulators Targets the Committed Step of de Novo Fatty Acid Biosynthesis

et al. 2016

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ORCID ID: 0000-0002-9686-9645 (V.L.)Acetyl-CoA carboxylase (ACCase) catalyzes the committed step of de novo fatty acid biosynthesis. In prokaryotes, green algae, and most plants, this enzyme is a heteromeric complex requiring four different subunits for activity. The plant complex is recalcitrant to conventional purification schemes and hence the structure and composition of the full assembly have been unclear. In vivo coimmunoprecipitation using subunit-specific antibodies identified a novel family of proteins in Arabidopsis thaliana annotated as biotin/lipoyl attachment domain containing (BADC) proteins. Results from yeast two-hybrid and coexpression in Escherichia coli confirmed that all three BADC isoforms interact with the two biotin carboxyl carrier protein (BCCP) isoforms of Arabidopsis ACCase. These proteins resemble BCCP subunits but are not biotinylated due to a mutated biotinylation motif. We demonstrate that BADC proteins significantly inhibit ACCase activity in both E. coli and Arabidopsis. Targeted gene silencing of BADC isoform 1 in Arabidopsis significantly increased seed oil content when normalized to either mass or individual seed. We conclude the BADC proteins are ancestral BCCPs that gained a new function as negative regulators of ACCase after initial loss of the biotinylation motif. A functional model is proposed.

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“…Despite the fact that they are difficult to study and not identifiable at the gene or transcript levels, the existence of large molecular devices (multiprotein complexes) in the cytosol is very well established (Wiggins 1990;Book et al 2010;Olinares et al 2010). Indeed, it is possible that in an intact system, there are few 'soluble' enzymes; they only appear when cells are disrupted and their contents diluted.…”

Section: Sodium Toxicity Cellular Water and Cytosolic Conditionsmentioning

confidence: 99%

The integration of activity in saline environments: problems and perspectives

Cheeseman

2013

Functional Plant Biol.

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Abstract. The successful integration of activity in saline environments requires flexibility of responses at all levels, from genes to life cycles. Because plants are complex systems, there is no 'best' or 'optimal' solution and with respect to salt, glycophytes and halophytes are only the ends of a continuum of responses and possibilities. In this review, I briefly examine seven major aspects of plant function and their responses to salinity including transporters, secondary stresses, carbon acquisition and allocation, water and transpiration, growth and development, reproduction, and cytosolic function and 'integrity'. I conclude that new approaches are needed to move towards understanding either organismal integration or 'salt tolerance', especially cessation of protocols dependent on sudden, often lethal, shock treatments and the embracing of systems level resources. Some of the tools needed to understand the integration of activity and even 'salt stress' are already in hand, such as those for whole-transcriptome analysis. Others, ranging from discovery studies of the nature of the cytosol to expanded tool kits for proteomic, metabolomic and epigenomic studies, still need to be further developed. After resurrecting the distinction between applied stress and the resultant strain and noting that with respect to salinity, the strain is manifest in changes at all -omic levels, I conclude that it should be possible to model and quantify stress responses.

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Megadalton Complexes in the Chloroplast Stroma of Arabidopsis thaliana Characterized by Size Exclusion Chromatography, Mass Spectrometry, and Hierarchical Clustering

Cited by 178 publications

References 164 publications

Organelle–nucleus cross-talk regulates plant intercellular communication via plasmodesmata

Organelle–nucleus cross-talk regulates plant intercellular communication via plasmodesmata

A Family of Negative Regulators Targets the Committed Step of de Novo Fatty Acid Biosynthesis

The integration of activity in saline environments: problems and perspectives

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