Insights into the complex 3-D architecture of thylakoid membranes in unicellular cyanobacterium <i>Cyanothece</i> sp. ATCC 51142

Liberton, Michelle; Austin, Jotham R.; Berg, R. Howard; Pakrasi, Himadri B.

doi:10.4161/psb.6.4.14946

Cited by 20 publications

(14 citation statements)

References 13 publications

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“…Over the last decade, there has been progress in the 3D visualization of photosynthetic structures. Much of this work has focused on cyanobacteria ( Nevo et al, 2007 ; Ting et al, 2007 ; Konorty et al, 2008 , 2009 ; Iancu et al, 2010 ; Liberton et al, 2011a , 2011b ), as the small size of these prokaryotes allows imaging by whole-cell tomography. With the exception of a few very small cells ( Henderson et al, 2007 ), more complex eukaryotic specimens must be thinned to make them transparent to the electron beam.…”

Section: Introductionmentioning

confidence: 99%

Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography

Engel

Schaffer

Cuellar

et al. 2015

eLife

286

295

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Chloroplast function is orchestrated by the organelle's intricate architecture. By combining cryo-focused ion beam milling of vitreous Chlamydomonas cells with cryo-electron tomography, we acquired three-dimensional structures of the chloroplast in its native state within the cell. Chloroplast envelope inner membrane invaginations were frequently found in close association with thylakoid tips, and the tips of multiple thylakoid stacks converged at dynamic sites on the chloroplast envelope, implicating lipid transport in thylakoid biogenesis. Subtomogram averaging and nearest neighbor analysis revealed that RuBisCO complexes were hexagonally packed within the pyrenoid, with ∼15 nm between their centers. Thylakoid stacks and the pyrenoid were connected by cylindrical pyrenoid tubules, physically bridging the sites of light-dependent photosynthesis and light-independent carbon fixation. Multiple parallel minitubules were bundled within each pyrenoid tubule, possibly serving as conduits for the targeted one-dimensional diffusion of small molecules such as ATP and sugars between the chloroplast stroma and the pyrenoid matrix.DOI: http://dx.doi.org/10.7554/eLife.04889.001

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Section: Introductionmentioning

confidence: 99%

Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography

Engel

Schaffer

Cuellar

et al. 2015

eLife

286

295

View full text Add to dashboard Cite

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“…Similarly, the thylakoids traversing the pyrenoid of the red algae Porphyridium cruentum lack PSII ( McKay and Gibbs, 1990 ), while in the dinoflagellate Gonyaulax polyedra during times of high carbon fixation the Rubisco is spatially relocated to pyrenoids near the cell center away from the O 2 -evolving light-harvesting reactions ( Nassoury et al , 2001 ). Similarly in cyanobacteria, the carboxysomes localize to the cell interior away from the PSII thylakoids lining the cell periphery ( Liberton et al , 2011 ). These strategies for spatially separating O 2 production away from Rubisco appear to be key components of the CCM.…”

Section: Resultsmentioning

confidence: 99%

The role of Rubisco kinetics and pyrenoid morphology in shaping the CCM of haptophyte microalgae

Heureux

Young

Whitney

et al. 2017

Journal of Experimental Botany

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“…Although, many processes occurring at/in TMs have been analyzed to a great extent and are well described, the biogenesis and dynamics of the TM itself are yet to be fully understood (Nickelsen and Zerges, 2013; Rast et al, 2015). In fact, in both cyanobacteria and chloroplast, the structure of the TM network is highly dynamic and fusion of different TM stacks have already been observed in cyanobacteria as well as in chloroplasts of green algae and higher plants (Shimoni et al, 2005; van de Meene et al, 2006; Nevo et al, 2007; Chuartzman et al, 2008; Liberton et al, 2011a,b; van de Meene et al, 2012; Engel et al, 2015). Such dynamic (re)organization of the TM network appears to be critical for optimizing the photosynthetic light reactions (Chuartzman et al, 2008; Barthel et al, 2012; Charuvi et al, 2012; Nevo et al, 2012; Pribil et al, 2014; Flori et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

The Fusion Activity of IM30 Rings Involves Controlled Unmasking of the Fusogenic Core

Thurotte

Schneider

2019

Front. Plant Sci.

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The inner membrane-associated protein of 30 kDa (IM30, also known as Vipp1) is required for thylakoid membrane biogenesis and maintenance in cyanobacteria and chloroplasts. The protein forms large rings of ∼2 MDa and triggers membrane fusion in presence of Mg2+. Based on the here presented observations, IM30 rings are built from dimers of dimers, and formation of these tetrameric building blocks is driven by interactions of the central coiled-coil, formed by helices 2 and 3, and stabilized via additional interactions mainly involving helix 1. Furthermore, helix 1 as well as C-terminal regions of IM30 together negatively regulate ring-ring contacts. We propose that IM30 rings represent the inactive form of IM30, and upon binding to negatively charged membrane surfaces, the here identified fusogenic core of IM30 rings eventually interacts with the lipid bilayer, resulting in membrane destabilization and membrane fusion. Unmasking of the IM30 fusogenic core likely is controlled by Mg2+, which triggers rearrangement of the IM30 ring structure.

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Insights into the complex 3-D architecture of thylakoid membranes in unicellular cyanobacterium Cyanothece sp. ATCC 51142

Cited by 20 publications

References 13 publications

Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography

Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography

The role of Rubisco kinetics and pyrenoid morphology in shaping the CCM of haptophyte microalgae

The Fusion Activity of IM30 Rings Involves Controlled Unmasking of the Fusogenic Core

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