Chloroplast Photorelocation Movement

Suetsugu, Noriyuki; Wada, Masamitsu

doi:10.1007/978-3-540-68696-5_8

Cited by 17 publications

(15 citation statements)

References 145 publications

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“…Chloroplasts change their positions in cells according to the quality, intensity, and position of the incident light; they move from the periclinal to the anticlinal wall in strong-intensity light (the avoidance response); conversely, they accumulate at the periclinal wall of palisade cells in low-intensity light (the accumulation response). This type of chloroplast movement is a common and dynamic phenomenon found in almost all of the land plants that have been tested to date Suetsugu and Wada, 2009).…”

Section: Introductionmentioning

confidence: 99%

Rapid Severing and Motility of Chloroplast-Actin Filaments Are Required for the Chloroplast Avoidance Response inArabidopsis

et al. 2013

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Phototropins (phot1 and phot2 in Arabidopsis thaliana) relay blue light intensity information to the chloroplasts, which move toward weak light (the accumulation response) and away from strong light (the avoidance response). Chloroplast-actin (cpactin) filaments are vital for mediating these chloroplast photorelocation movements. In this report, we examine in detail the cp-actin filament dynamics by which the chloroplast avoidance response is regulated. Although stochastic dynamics of cortical actin fragments are observed on the chloroplasts, the basic mechanisms underlying the disappearance (including severing and turnover) of the cp-actin filaments are regulated differently from those of cortical actin filaments. phot2 plays a pivotal role in the strong blue light-induced severing and random motility of cp-actin filaments, processes that are therefore essential for asymmetric cp-actin formation for the avoidance response. In addition, phot2 functions in the bundling of cpactin filaments that is induced by dark incubation. By contrast, the function of phot1 is dispensable for these responses. Our findings suggest that phot2 is the primary photoreceptor involved in the rapid reorganization of cp-actin filaments that allows chloroplasts to change direction rapidly and control the velocity of the avoidance movement according to the light's intensity and position.

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Section: Introductionmentioning

confidence: 99%

Rapid Severing and Motility of Chloroplast-Actin Filaments Are Required for the Chloroplast Avoidance Response inArabidopsis

et al. 2013

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“…Nevertheless, because of the sessile nature of plants, the control of chloroplast location is particularly important to respond optimally to light stimuli. For example, chloroplast movement allows plants to adequately adapt to the constant changes in light levels resulting from earth's rotation, weather, seasons, and different overlapping patterns between leaves (Suetsugu and Wada ; Morita and Nakamura ; Kong and Wada ).…”

Section: Introductionmentioning

confidence: 99%

The kinesin‐like proteins, KAC1/2, regulate actin dynamics underlying chloroplast light‐avoidance inPhyscomitrella patens

Shen

Liu

Bibeau

et al. 2015

JIPB

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In plants, light determines chloroplast position; these organelles show avoidance and accumulation responses in high and low fluence-rate light, respectively. Chloroplast motility in response to light is driven by cytoskeletal elements. The actin cytoskeleton mediates chloroplast photorelocation responses in Arabidopsis thaliana. In contrast, in the moss Physcomitrella patens, both, actin filaments and microtubules can transport chloroplasts. Because of the surprising evidence that two kinesin-like proteins (called KACs) are important for actin-dependent chloroplast photorelocation in vascular plants, we wanted to determine the cytoskeletal system responsible for the function of these proteins in moss. We performed genespecific silencing using RNA interference in P. patens. We confirmed existing reports using gene knockouts, that PpKAC1 and PpKAC2 are required for chloroplast dispersion under uniform white light conditions, and that the two proteins are functionally equivalent. To address the specific cytoskeletal elements responsible for motility, this loss-offunction approach was combined with cytoskeleton-targeted drug studies. We found that, in P. patens, these KACs mediate the chloroplast light-avoidance response in an actin filamentdependent, rather than a microtubule-dependent manner. Using correlation-decay analysis of cytoskeletal dynamics, we found that PpKAC stabilizes cortical actin filaments, but has no effect on microtubule dynamics.

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“…Chloroplasts move to low-intensity light to capture photosynthetic light efficiently (accumulation response), whereas they escape from high-intensity light to avoid Structure and activity of JAC1 J-domain implicate the involvement of the cochaperone activity with HSC70 in chloroplast photorelocation movement Noriyuki photodamage (avoidance response). [1][2][3] Blue light is the most effective to induce chloroplast movement in various plant species. Blue light receptors, phototropins (phot), mediate chloroplast photorelocation movement in green plants.…”

Section: An Overview Of the Molecular Components For Chloroplast Photmentioning

confidence: 99%

“…Blue light receptors, phototropins (phot), mediate chloroplast photorelocation movement in green plants. 1,2 With a few exceptions, plants exclusively utilize actin filaments in the chloroplast motility system. 1,2,4 Recent molecular genetic analyses using Arabidopsis thaliana identified various molecular components.…”

Section: An Overview Of the Molecular Components For Chloroplast Photmentioning

confidence: 99%

Structure and activity of JAC1 J-domain implicate the involvement of the cochaperone activity with HSC70 in chloroplast photorelocation movement

Suetsugu

Takano

Kohda

et al. 2010

Plant Signaling & Behavior

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Chloroplast photorelocation movement towards weak light and away from strong light is essential for plants to adapt to the fluctuation of ambient light conditions. In the previous study, we showed that blue light receptor phototropins mediated blue light-induced chloroplast movement in Arabidopsis by regulating short actin filaments localized at the chloroplast periphery (cp-actin filaments) rather than actin cables in the cytoplasm. However, the signaling pathway for the chloroplast photorelocation movement is still unclear. We also identified JAC1 (J-domain protein required for chloroplast accumulation response 1) as an essential component for the accumulation response and dark positioning in Arabidopsis. We recently determined the crystal structure of the J-domain of JAC1. The JAC1 J-domain has a positively charged surface, which forms a putative interface with the Hsc70 chaperone by analogy to that of bovine auxilin. Furthermore, the mutation of the highly conserved HPD motif in the JAC1 J-domain impaired the in vivo activity of JAC1. These data suggest that JAC1 cochaperone activity with HSC70 is essential for chloroplast photorelocation movement.

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Chloroplast Photorelocation Movement

Cited by 17 publications

References 145 publications

Rapid Severing and Motility of Chloroplast-Actin Filaments Are Required for the Chloroplast Avoidance Response inArabidopsis

Rapid Severing and Motility of Chloroplast-Actin Filaments Are Required for the Chloroplast Avoidance Response inArabidopsis

The kinesin‐like proteins, KAC1/2, regulate actin dynamics underlying chloroplast light‐avoidance inPhyscomitrella patens

Structure and activity of JAC1 J-domain implicate the involvement of the cochaperone activity with HSC70 in chloroplast photorelocation movement

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