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A Cyclic GMP-Dependent K+ Channel in the Blastocladiomycete Fungus Blastocladiella emersonii.
- Source :
-
Eukaryotic cell [Eukaryot Cell] 2015 Sep; Vol. 14 (9), pp. 958-63. Date of Electronic Publication: 2015 Jul 06. - Publication Year :
- 2015
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Abstract
- Phototaxis in flagellated zoospores of the aquatic fungus Blastocladiella emersonii depends on a novel photosensor, Blastocladiella emersonii GC1 (BeGC1), comprising a type I (microbial) rhodopsin fused to a guanylyl cyclase catalytic domain, that produces the conserved second messenger cyclic GMP (cGMP). The rapid and transient increase in cGMP levels during the exposure of zoospores to green light was shown to be necessary for phototaxis and dependent on both rhodopsin function and guanylyl cyclase activity. It is noteworthy that BeGC1 was localized to the zoospore eyespot apparatus, in agreement with its role in the phototactic response. A putative cyclic nucleotide-gated channel (BeCNG1) was also identified in the genome of the fungus and was implicated in flagellar beating via the action of a specific inhibitor (l-cis-diltiazem) that compromised zoospore motility. Here we show that B. emersonii expresses a K(+) channel that is activated by cGMP. The use of specific channel inhibitors confirmed the activation of the channel by cGMP and its K(+) selectivity. These characteristics are consistent with the function of an ion channel encoded by the BeCNG1 gene. Other blastocladiomycete fungi, such as Allomyces macrogynus and Catenaria anguillulae, possess genes encoding a similar K(+) channel and the rhodopsin-guanylyl cyclase fusion protein, while the genes encoding both these proteins are absent in nonflagellated fungi. The presence of these genes as a pair seems to be an exclusive feature of blastocladiomycete fungi. Taken together, these data demonstrate that the B. emersonii cGMP-activated K(+) channel is involved in the control of zoospore motility, most probably participating in the cGMP-signaling pathway for the phototactic response of the fungus.<br /> (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Subjects :
- Blastocladiomycota genetics
Blastocladiomycota physiology
Cyclic GMP metabolism
Cyclic Nucleotide-Gated Cation Channels genetics
Fungal Proteins genetics
Membrane Potentials
Potassium metabolism
Potassium Channels genetics
Spores, Fungal metabolism
Blastocladiomycota metabolism
Cyclic Nucleotide-Gated Cation Channels metabolism
Fungal Proteins metabolism
Potassium Channels metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1535-9786
- Volume :
- 14
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Eukaryotic cell
- Publication Type :
- Academic Journal
- Accession number :
- 26150416
- Full Text :
- https://doi.org/10.1128/EC.00087-15