Photosensory transduction in unicellular eukaryotes: A comparison between related ciliates Blepharisma japonicum and Stentor coeruleus and photoreceptor cells of higher organisms

Sobierajska, Katarzyna; Fabczak, Hanna; Fabczak, S.

doi:10.1016/j.jphotobiol.2006.01.005

Cited by 24 publications

(15 citation statements)

References 79 publications

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“…Signaling mainly involved GTP-binding proteins (G proteins). In Alveolata, G proteins are involved in sensory/ mechanical signal transduction in dinoflagellates (e.g., the response to shear stress triggering bioluminescence [7]) and in phototransduction in ciliates (45). Calmodulin and calmodulin-related proteins were also highly represented in our library.…”

Section: Discussionmentioning

confidence: 99%

Gene Expression in Proliferating Cells of the Dinoflagellate Alexandrium catenella (Dinophyceae)

Toulza

Shin

Blanc

et al. 2010

Appl Environ Microbiol

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Understanding the conditions leading to harmful algal blooms, especially those produced by toxic dinoflagellate species, is important for environmental and health safety. In addition to investigations into the environmental conditions necessary for the formation of toxic blooms, we postulate that investigating gene expression in proliferating cells is essential for understanding bloom dynamics. Expressed sequence tags were produced from cultured cells of the toxic dinoflagellate Alexandrium catenella sampled during the initiation phase of growth using Sanger's method and by 454 pyrosequencing. A significant proportion of identified genes (ca. 25%) represented enzymes and proteins that participate in a variety of cellular regulatory mechanisms that may characterize proliferating cells, e.g., control of the cell cycle and division, regulation of transcription, translation and posttranslational protein modifications, signaling, intracellular trafficking, and transport. All of the several genes selected for gene expression assays due to their involvement in metabolism and the cell cycle were overexpressed during exponential growth. These data will be useful for investigating the mechanisms underlying growth and toxin production in toxic Alexandrium species and for studying and monitoring the development of toxic blooms.

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Section: Discussionmentioning

confidence: 99%

Gene Expression in Proliferating Cells of the Dinoflagellate Alexandrium catenella (Dinophyceae)

Toulza

Shin

Blanc

et al. 2010

Appl Environ Microbiol

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“…This mechanism for the biased movement of M. xanthus in a repellent gradient is consistent with all experimental results without the requirement of adaptation and without invoking spatial sensing. This is also somewhat reminiscent of the photophobic or light‐induced avoidance response by many phototrophic microbes (Diehn, 1973; Spudich and Bogomolni, 1984; Sprenger et al ., 1993; Lucia et al ., 1996; Armitage and Hellingwerf, 2003; Sobierajska et al ., 2006).…”

Section: Discussionmentioning

confidence: 99%

Chemotaxis mediated by NarX–FrzCD chimeras and nonadapting repellent responses in Myxococcus xanthus

Black

Mauriello

et al. 2007

Molecular Microbiology

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SummaryMyxococcus xanthus requires gliding motility for swarming and fruiting body formation. It uses the Frz chemosensory pathway to regulate cell reversals. FrzCD is a cytoplasmic chemoreceptor required for sensing effectors for this pathway. NarX is a transmembrane sensor for nitrate from Escherichia coli. In this study, two NarX-FrzCD chimeras were constructed to investigate M. xanthus chemotaxis: NazDF contains the N-terminal sensory module of NarX fused to the C-terminal signalling domain of FrzCD; NazDR is similar except that it contains a G51R mutation in the NarX domain known to reverse the signalling output of a NarX-Tar chimera to nitrate. We report that while nitrate had no effect on the wild type, it decreased the reversal frequency of M. xanthus expressing NazDF and increased that of M. xanthus expressing NazDR. These results show that directional motility in M. xanthus can be regulated independently of cellular metabolism and physiology. Surprisingly, the NazDR strain failed to adapt to nitrate in temporal assays as did the wild type to known repellents. The lack of temporal adaptation to negative stimuli appears to be a general feature in M. xanthus chemotaxis. Thus, the appearance of biased movements by M. xanthus in repellent gradients is likely due to the inhibition of net translocation by repellents.

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“…The observed decrease in phosphorylation of this protein correlates with the motile photophobic response elicited by photoactivation of the specific cellular photoreceptor system present in Blepharisma (Tao et al, 1994;Maeda et al, 1997;Fabczak, 2000b;Matsuoka et al, 2000;Sobierajska et al, 2006). As reported recently, the deduced amino acid sequence of the ciliate phosphoprotein exhibits high levels of homology to phosducins of other organisms (Sobierajska et al, 2006). The Blepharisma Pdc homolog also contains an amino acid motif (gi_124020703; GenBank accession no.…”

Section: Discussionmentioning

confidence: 74%

Phosducin interacts with the G-protein βγ-dimer of ciliate protozoanBlepharisma japonicumupon illumination

Sobierajska

Fabczak

2007

Journal of Experimental Biology

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SUMMARY Immunological techniques and high-resolution FRET analysis were employed to investigate the in vivo colocalization and interaction of phosducin(Pdc) with the βγ-subunits of G-protein (Gβγ) in the ciliate Blepharisma japonicum. Immunological techniques revealed that illumination of cells resulted in a decrease in phosphorylation levels of Pdc and its colocalization with Gβγ. The observed light-induced Pdc dephosphorylation was also accompanied by significant enhancement of Gβγ binding by this molecule. Possible formation of the Pdc–Gβγ complex in cells exposed to light was corroborated by FRET between these proteins. Treatment of cells with okadaic acid, an inhibitor of phosphatase activity, entirely prevented Pdc dephosphorylation by light, colocalization of this phosphoprotein with Gβγ and generation of the Pdc–Gβγ complex. Cell fractionation and immunoblotting revealed that in cells exposed to light, the formation of Pdc–Gβγ complex and its translocation into the cytoplasm occur simultaneously with a change in the gel migration of Gβ. Moreover, a 33 kDa immunoanalog of 14-3-3 protein was identified and we showed that this protein is bound by phosphorylated Pdc in a cell adapted to darkness. The results of this study provide additional detailed characterization of the functional properties of the ciliate Pdc. The likely functional role of Pdc in Blepharisma is discussed.

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Photosensory transduction in unicellular eukaryotes: A comparison between related ciliates Blepharisma japonicum and Stentor coeruleus and photoreceptor cells of higher organisms

Cited by 24 publications

References 79 publications

Gene Expression in Proliferating Cells of the Dinoflagellate Alexandrium catenella (Dinophyceae)

Gene Expression in Proliferating Cells of the Dinoflagellate Alexandrium catenella (Dinophyceae)

Chemotaxis mediated by NarX–FrzCD chimeras and nonadapting repellent responses in Myxococcus xanthus

Phosducin interacts with the G-protein βγ-dimer of ciliate protozoanBlepharisma japonicumupon illumination

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