Photosynthetic electron flow to oxygen and diffusion of hydrogen peroxide through the chloroplast envelope via aquaporins

Borisova, Maria M Mubarakshina; Kozuleva, Marina; Rudenko, Natalia N.; Naydov, Ilya A.; Klenina, I. B.; Иванов, Б. Н.

doi:10.1016/j.bbabio.2012.02.036

Cited by 107 publications

(44 citation statements)

References 58 publications

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“…Till now, several ions or small molecules have been considered as potential AQP1 inhibitors, including Hg 2+ [26], TEA + [27], AZA [28] and AqB013 [29]. Among these inhibitors, AZA was firstly indentified by our lab to act as AQP1 inhibitor [11], [28], and after that several groups have confirmed this finding [12], [13], [30]–[32]. Also, based on structure of AZA and bumetanide, novel synthesized compound was discovered to be a putative inhibitor of AQP1 [29], [33].…”

Section: Discussionmentioning

confidence: 97%

Aquaporin-1 Translocation and Degradation Mediates the Water Transportation Mechanism of Acetazolamide

Zhang

Gao

et al. 2012

PLoS ONE

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BackgroundDiuretic agents are widely used on the treatment of water retention related diseases, among which acetazolamide (AZA) acts originally as a carbonic anhydrase (CA) inhibitor. Aquaporin-1 (AQP1) being located in renal proximal tubules is required for urine concentration. Previously our lab has reported AZA putatively modulated AQP1. Aim of this study is to testify our hypothesis that regulating AQP1 may mediate diuretic effect of AZA.Methodology/Principal FindingsFor in vivo study, we utilized Sprague Dawley rats, as well as AQP1 knock-out (AQP1−/−) mice to examine urine volume, and human kidney-2 (HK-2) cell line was used for in vitro mechanism study. In our present study we found that AZA decreased CAs activity initially but the activity gradually recovered. Contrarily, diuretic effect was consistently significant. AQP1 protein expression was significantly decreased on day 7 and 14. By utilizing AQP1−/− mice, we found diuretic effect of AZA was cancelled on day 14, while urine volume continuously increased in wild-type mice. Surface plasmon resonance (SPR) results indicated AQP1 was physiologically bound by myosin heavy chain (MHC), immunoprecipitation and immunofluorescence results confirmed this protein interaction. In vitro study results proved AZA facilitated AQP1 translocation onto cell membrane by promoting interaction with MHC, dependent on ERK/ myosin light chain kinase (MLCK) pathway activation. MHC inhibitor BDM and ERK inhibitor U0126 both abolished above effect of AZA. Eventually AZA induced AQP1 ubiquitination, while proteasome inhibitor MG132 reversed AZA's down-regulating effect upon AQP1.Conclusions/SignificanceOur results identified AZA exerted diuretic effect through an innovative mechanism by regulating AQP1 and verified its inhibitory mechanism was via promoting MHC-dependent translocation onto cell membrane and then ubiquitin mediated degradation, implicating a novel mechanism and target for diuretic agent discovering.

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Section: Discussionmentioning

confidence: 97%

Aquaporin-1 Translocation and Degradation Mediates the Water Transportation Mechanism of Acetazolamide

Zhang

Gao

et al. 2012

PLoS ONE

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“…To move from the chloroplast stroma, H 2 O 2 must move across the inner chloroplast membrane, the outer chloroplast membrane and the nuclear envelope to finally arrive in the nucleus. H 2 O 2 cannot freely diffuse across the chloroplast envelope membranes and instead uses aquaporins (Mubarakshina Borisova et al, 2012). H 2 O 2 most likely moves across the nuclear envelope through nuclear pores, which appear to be in close proximity to stromules (Figure 5E).…”

Section: Discussionmentioning

confidence: 99%

Chloroplast Stromules Function during Innate Immunity

et al. 2015

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Summary Inter-organellar communication is vital for successful innate immune responses that confer defense against pathogens. However, little is known about how chloroplasts, which are a major production site of pro-defense molecules, communicate and coordinate with other organelles during defense. Here we show that chloroplasts send out dynamic tubular extensions called stromules during innate immunity or exogenous application of the pro-defense signals, hydrogen peroxide (H2O2) and salicylic acid (SA). Interestingly, numerous stromules surround nuclei during defense response and these connections correlate with an accumulation of chloroplast-localized NRIP1 defense protein and H2O2 in the nucleus. Furthermore, silencing and knockout of CHloroplast Unusual Positioning 1 (CHUP1) that encodes a chloroplast outer envelope protein constitutively induces stromules in the absence of pathogen infection and enhances programmed cell death (PCD). These results support a model in which stromules aid in the amplification and/or transport of pro-defense signals into the nucleus and other subcellular compartments during immunity.

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“…Diffusion of H 2 O 2 from chloroplasts has also been demonstrated in vitro (Mubarakshina et al, 2010). Aquaporins in the chloroplast envelope ( Figure 2 ) seem to be involved in this H 2 O 2 leakage (Borisova et al, 2012), but how the aquaporins are regulated is unknown. In any case, H 2 O 2 itself is not likely to be the retrograde signaling substance that directly affects nuclear gene expression.…”

Section: Chloroplastic Ros As Signalsmentioning

confidence: 99%

ROS-talk – how the apoplast, the chloroplast, and the nucleus get the message through

et al. 2012

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The production of reactive oxygen species (ROS) in different plant subcellular compartments is the hallmark of the response to many stress stimuli and developmental cues. The past two decades have seen a transition from regarding ROS as exclusively cytotoxic agents to being considered as reactive compounds which participate in elaborate signaling networks connecting various aspects of plant life. We have now arrived at a stage where it has become increasingly difficult to disregard the communication between different types and pools of ROS. Production of ROS in the extracellular space, the apoplast, can influence their generation in the chloroplast and both can regulate nuclear gene expression. In spite of existing information on these signaling events, we can still barely grasp the mechanisms of ROS signaling and communication between the organelles. In this review, we summarize evidence that supports the mutual influence of extracellular and chloroplastic ROS production on nuclear gene regulation and how this interaction might occur. We also reflect on how, and via which routes signals might reach the nucleus where they are ultimately integrated for transcriptional reprogramming. New ideas and approaches will be needed in the future to address the pressing questions of how ROS as signaling molecules can participate in the coordination of stress adaptation and development and how they are involved in the chatter of the organelles.

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Photosynthetic electron flow to oxygen and diffusion of hydrogen peroxide through the chloroplast envelope via aquaporins

Cited by 107 publications

References 58 publications

Aquaporin-1 Translocation and Degradation Mediates the Water Transportation Mechanism of Acetazolamide

Aquaporin-1 Translocation and Degradation Mediates the Water Transportation Mechanism of Acetazolamide

Chloroplast Stromules Function during Innate Immunity

ROS-talk – how the apoplast, the chloroplast, and the nucleus get the message through

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