Actin-based photo-orientation movement of chloroplasts in plant cells

Takagi, Shingo

doi:10.1242/jeb.00215

Cited by 93 publications

(75 citation statements)

References 41 publications

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“…Since the cytoskeleton is known to function in the positioning and anchorage of organelles (Morris, 2003;Starr & Han, 2003;Takagi, 2003), we assessed whether microtubules or actin filaments were responsible for the anchorage of peripheral punctate spots and tubules. Therefore, protoplasts infected with CPMV MP-GFP were treated with inhibitors of microtubules and actin filaments (oryzalin and latrunculin B) as described previously (Pouwels et al, 2002b), and at 42 h p.i., these protoplasts were embedded in 1?3 % LMP agarose containing the inhibitors.…”

Section: Resultsmentioning

confidence: 99%

Studies on the origin and structure of tubules made by the movement protein of Cowpea mosaic virus

Pouwels¹,

Velden²,

Willemse³

et al. 2004

Journal of General Virology

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Cowpea mosaic virus (CPMV) moves from cell to cell by transporting virus particles via tubules formed through plasmodesmata by the movement protein (MP). On the surface of protoplasts, a fusion between the MP and the green fluorescent protein forms similar tubules and peripheral punctate spots. Here it was shown by time-lapse microscopy that tubules can grow out from a subset of these peripheral punctate spots, which are dynamic structures that seem anchored to the plasma membrane. Fluorescence resonance energy transfer experiments showed that MP subunits interacted within the tubule, where they were virtually immobile, confirming that tubules consist of a highly organized MP multimer. Fluorescence recovery after photobleaching experiments with protoplasts, transiently expressing fluorescent plasma membrane-associated proteins of different sizes, indicated that tubules made by CPMV MP do not interact directly with the surrounding plasma membrane. These experiments indicated an indirect interaction between the tubule and the surrounding plasma membrane, possibly via a host plasma membrane protein. INTRODUCTIONFor successful systemic infection, a plant virus must spread throughout the plant, a process that starts with transport from the initially infected cell to neighbouring uninfected cells (cell-to-cell movement) and is followed by transport through the phloem into roots and young developing leaves (systemic movement). Since plant viruses cannot pass through the rigid cell wall, they have evolved ways of exploiting plasmodesmata, the naturally occurring transport channels present between plant cells (Haywood et al., 2002). Normally, only small molecules are able to pass through plasmodesmata, but plant viruses encode one or more proteins, the so-called movement proteins (MPs), that modify the structure of plasmodesmata in such a way that viral transport is enabled. So far, two basic principles for cell-to-cell movement of plant viruses have been described: tubule-guided movement of virus particles and movement as ribonucleoprotein complexes (Lazarowitz & Beachy, 1999).Cowpea mosaic virus (CPMV), a positive-stranded, bipartite RNA virus belonging to the family Comoviridae, moves from cell to cell by transporting virus particles using tubular structures, which connect the infected cell to the neighbouring uninfected cell (Pouwels et al., 2002a). Immunogold labelling has shown that the CPMV MP is present in these tubular structures (van Lent et al., 1990). On the surface of CPMV-infected protoplasts, similar tubular structures are formed, which protrude up to 20 mm into the culture medium, are tightly surrounded by the plasma membrane and have the same ultrastructure as tubules in plant tissue (van Lent et al., 1991). Remarkably, tubules are also formed on protoplasts transiently expressing MP , showing that MP is the only viral protein required for tubule formation. So far, protoplasts have proved extremely useful as a model system for studying targeting and assembly of both wt and mutant MPs (Bertens et al., 20...

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Section: Resultsmentioning

confidence: 99%

Studies on the origin and structure of tubules made by the movement protein of Cowpea mosaic virus

Pouwels¹,

Velden²,

Willemse³

et al. 2004

Journal of General Virology

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“…If large numbers of cells are aligned in a plant structure, they can cause macroscopic changes in shape. This mechanism is responsible for phototropism or sun tracking (Takagi 2002) and the large and fast …”

Section: Soft Active Plant Structuresmentioning

confidence: 99%

Soft Robotics: Biological Inspiration, State of the Art, and Future Research

Trivedi

Rahn

Kier

et al. 2008

Applied Bionics and Biomechanics

1,192

536

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Traditional robots have rigid underlying structures that limit their ability to interact with their environment. For example, conventional robot manipulators have rigid links and can manipulate objects using only their specialised end effectors. These robots often encounter difficulties operating in unstructured and highly congested environments. A variety of animals and plants exhibit complex movement with soft structures devoid of rigid components. Muscular hydrostats (e.g. octopus arms and elephant trunks) are almost entirely composed of muscle and connective tissue and plant cells can change shape when pressurised by osmosis. Researchers have been inspired by biology to design and build soft robots. With a soft structure and redundant degrees of freedom, these robots can be used for delicate tasks in cluttered and/or unstructured environments. This paper discusses the novel capabilities of soft robots, describes examples from nature that provide biological inspiration, surveys the state of the art and outlines existing challenges in soft robot design, modelling, fabrication and control.

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“…Close links of chloroplasts with actin filaments were shown in vascular plants and algae (Takagi, 2003). Actin filaments are attached to the surface of chloroplasts and regulate chloroplast positioning and plastid stromule movement (Jouhet and Gray, 2009).…”

Section: The Pten Domain Mediates the Association Of Fh5 With Chloropmentioning

confidence: 99%

RICE MORPHOLOGY DETERMINANTEncodes the Type II Formin FH5 and Regulates Rice Morphogenesis

et al. 2011

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Multicellular organisms contain a large number of formins; however, their physiological roles in plants remain poorly understood. Here, we reveal that formin homology 5 (FH5), a type II formin mutated in rice morphology determinant (rmd), plays a crucial role in determining rice (Oryza sativa) morphology. FH5/RMD encodes a formin-like protein consisting of an N-terminal phosphatase tensin (PTEN)-like domain, an FH1 domain, and an FH2 domain. The rmd mutants display a bending growth pattern in seedlings, are stunted as adult plants, and have aberrant inflorescence (panicle) and seed shape. Cytological analysis showed that rmd mutants have severe cell elongation defects and abnormal microtubule and microfilament arrays. FH5/RMD is ubiquitously expressed in rice tissues, and its protein localization to the chloroplast surface is mediated by the PTEN domain. Biochemical assays demonstrated that recombinant FH5 protein can nucleate actin polymerization from monomeric G-actin or actin/profilin complexes, cap the barbed end of actin filaments, and bundle actin filaments in vitro. Moreover, FH5 can directly bind to and bundle microtubules through its FH2 domain in vitro. Our findings suggest that the rice formin protein FH5 plays a critical role in determining plant morphology by regulating actin dynamics and proper spatial organization of microtubules and microfilaments.

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Actin-based photo-orientation movement of chloroplasts in plant cells

Cited by 93 publications

References 41 publications

Studies on the origin and structure of tubules made by the movement protein of Cowpea mosaic virus

Studies on the origin and structure of tubules made by the movement protein of Cowpea mosaic virus

Soft Robotics: Biological Inspiration, State of the Art, and Future Research

RICE MORPHOLOGY DETERMINANTEncodes the Type II Formin FH5 and Regulates Rice Morphogenesis

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