Sodium regulation of GAF domain function

2007 ◽  
Vol 35 (5) ◽  
pp. 1032-1034 ◽  
Author(s):  
M.J. Cann
Keyword(s):  
Cyclic Nucleotides ◽  
Protein Domain ◽  
Genetic Ablation ◽  
Anabaena Pcc 7120 ◽  
Cyanobacterium Anabaena ◽  
Signal Changes ◽  
Sodium Regulation ◽  
Pcc 7120 ◽  
Camp And Cgmp

Cyclic nucleotide PDEs (phosphodiesterases) regulate cellular levels of cAMP and cGMP by controlling the rate of degradation. Several mammalian PDE isoforms possess N-terminal GAF (found in cGMP PDEs, Anabaena adenylate cyclases and Escherichia coli FhlA; where FhlA is formate hydrogen lyase transcriptional activator) domains that bind cyclic nucleotides. Similarly, the CyaB1 and CyaB2 ACs (adenylate cyclases) of the cyanobacterium Anabaena PCC 7120 bind cAMP through one (CyaB1) or two (CyaB2) N-terminal GAF domains and mediate autoregulation of the AC domain. Sodium inhibits the activity of CyaB1, CyaB2 and mammalian PDE2A in vitro through modulation of GAF domain function. Furthermore, genetic ablation of cyaB1 and cyaB2 gives rise to Anabaena strains defective in homoeostasis at limiting sodium. Sodium regulation of GAF domain function has therefore been conserved since the eukaryotic/prokaryotic divergence. The GAF domain is the first identified protein domain to directly sense and signal changes in environmental sodium.

A novel glutaredoxin domain-containing peroxiredoxin ‘All1541’ protects the N2-fixing cyanobacterium Anabaena PCC 7120 from oxidative stress

2012 ◽  
Vol 442 (3) ◽  
pp. 671-680 ◽  
Author(s):  
Manisha Banerjee ◽  
Anand Ballal ◽  
Shree K. Apte
Keyword(s):  
Oxidative Stress ◽  
Peroxidase Activity ◽  
Bioinformatic Analysis ◽  
Open Reading Frames ◽  
Site Directed Mutagenesis ◽  
Cysteine Residues ◽  
Anabaena Pcc 7120 ◽  
Cyanobacterium Anabaena ◽  
Pcc 7120

Prxs (peroxiredoxins) are ubiquitous thiol-based peroxidases that detoxify toxic peroxides. The Anabaena PCC 7120 genome harbours seven genes/ORFs (open reading frames) which have homology with Prxs. One of these (all1541) was identified to encode a novel Grx (glutaredoxin) domain-containing Prx by bioinformatic analysis. A recombinant N-terminal histidine-tagged All1541 protein was overexpressed in Escherichia coli and purified. Analysis with the protein alkylating agent AMS (4-acetamido-4′-maleimidyl-stilbene-2,2′-disulfonate) showed All1541 to form an intra-molecular disulfide bond. The All1541 protein used glutathione (GSH) more efficiently than Trx (thioredoxin) to detoxify H2O2. Deletion of the Grx domain from All1541 resulted in loss of GSH-dependent peroxidase activity. Employing site-directed mutagenesis, the cysteine residues at positions 50 and 75 were identified as peroxidatic and resolving cysteine residues respectively, whereas both the cysteine residues within the Grx domain (positions 181 and 184) were shown to be essential for GSH-dependent peroxidase activity. On the basis of these data, a reaction mechanism has been proposed for All1541. In vitro All1541 protein protected plasmid DNA from oxidative damage. In Anabaena PCC 7120, all1541 was transcriptionally activated under oxidative stress. Recombinant Anabaena PCC 7120 strain overexpressing All1541 protein showed superior oxidative stress tolerance to H2O2 as compared with the wild-type strain. The results suggest that the glutathione-dependent peroxidase All1541 plays an important role in protecting Anabaena from oxidative stress.

CGRP and ANF cause relaxation of opossum internal anal sphincter via different mechanisms

1991 ◽  
Vol 260 (5) ◽  
pp. G764-G769 ◽  
Author(s):  
S. Rattan ◽  
C. Moummi ◽  
S. Chakder
Keyword(s):  
Smooth Muscle ◽  
Anal Sphincter ◽  
Cyclic Nucleotides ◽  
Internal Anal Sphincter ◽  
Camp Content ◽  
Calcitonin Gene ◽  
Before And After ◽  
Camp And Cgmp

This investigation examined and compared the role of cyclic nucleotides in the mediation of internal anal sphincter (IAS) relaxation caused by the addition of neuropeptide calcitonin gene-related peptide (CGRP) and atrial natriuretic factor (ANF). The studies were performed in vitro on smooth muscle strips of opossum IAS. The relaxation produced by CGRP and ANF was examined before and after the addition of tetrodotoxin (TTX) (1 x 10(-6)M). At this concentration, TTX did not have any significant effect on the relaxation produced by either CGRP or ANF, suggesting that these peptides act directly on the smooth muscle. Addition of CGRP (3 x 10(-6) M) produced the maximal relaxation and significantly increased cAMP content without changing cGMP. On the other hand, addition of ANF (3 x 10(-6) M) caused a similar fall in IAS tension that was accompanied by a significant elevation in cGMP without any change in cAMP content. The rises in the levels of cyclic nucleotides preceded the onset of fall in the resting tension of IAS. Our results demonstrate that CGRP and ANF relax isolated strips of opossum IAS by their action directly at the smooth muscle and that this relaxation is associated with an increase in cAMP and cGMP, respectively. The studies suggest the presence of both cAMP and cGMP pathways in the IAS and that the relaxation of IAS smooth muscle in response to different peptides may occur via a specific intracellular biochemical pathway.

scholarly journals The generation and regulation of lymphocyte populations: evidence from differentiative induction systems in vitro.

1978 ◽  
Vol 147 (6) ◽  
pp. 1727-1743 ◽  
Author(s):  
M P Scheid ◽  
G Goldstein ◽  
E A Boyse
Keyword(s):  
B Cells ◽  
Cyclic Nucleotides ◽  
General Scheme ◽  
Pharmacological Agents ◽  
Inductive Effects ◽  
Camp Induction ◽  
Camp And Cgmp ◽  
Lymphocyte Populations ◽  
Two Populations

Results with a dual assay, for the induction of Thy-1+ T cells and of CR+ B cells from marker-negative precursors, confirm that thymopoietin is at present the only known selective inducer of prothymocytes. In contrast, various inducers, including ubiquitin, are active in both assays. Pharmacological evidence indicates that there are different cellular receptors for ubiquitin and thymopoietin. Prothymocytes and pro-CR+ B cells compose two distinct populations in bone marrow and spleen; their distribution in density gradients is different, and elimination of either population enriches the other proportionately. There are no noteworthy differences between induction of these two populations in regard to (a) kinetics, (b) dependence on temperature and protein synthesis, (c) activation by cAMP, and (d) inhibition by cGMP. The opposite inductive effects of cAMP and cGMP were corroborated by the use of pharmacological agents that raise or lower the levels of intracellular cyclic nucleotides. In contrast, a third induction assay, which monitors acquisition of the PC+ surface phenotype, indicates that this differentiative step, the last known for B cells, is initiated by cGMP and inhibited by cAMP. Induction of PC is also inhibited by thymopoietin, signifying that the inductive selectivity of thymopoietin is not due to restriction of its receptors to the T lineage cells. Rather it seems that receptors for thymopoietin occur also on PC-inducible and other B cells, although in this case geared biochemically to inhibition rather than expression of the succeeding gene program. This suggests a role for thymopoietin in the coordinated interregulation of lymphocyte classes, in addition to its better-known function as the thymic inducer of prothymocytes. Present data conform to a general scheme in which the cyclic nucleotides cAMP and cGMP, and agents that affect intracellular levels of these mediators, influence reciprocally the early and late (functional) phases of lymphocyte differentiation as a whole, while thymopoietin influences reciprocally the differentiation of the B and T classes of lymphocyte.

Isolation and Sequence of the Gene for Ferredoxin I from the Cyanobacterium Anabaena PCC 7120

1987 ◽  
pp. 793-795 ◽  
Author(s):  
Jawed Alam ◽  
Richard A. Whitaker ◽  
David W. Krogmann ◽  
Stephanie E. Curtis
Keyword(s):  
Anabaena Pcc 7120 ◽  
Cyanobacterium Anabaena ◽  
Ferredoxin I ◽  
Pcc 7120

Functional and mechanistic insights into the differential effect of the toxicant ‘Se(IV)’ in the cyanobacterium Anabaena PCC 7120

2021 ◽  
pp. 105839
Author(s):  
Manisha Banerjee ◽  
Prakash Kalwani ◽  
Dhiman Chakravarty ◽  
Beena Singh ◽  
Anand Ballal
Keyword(s):  
Differential Effect ◽  
Anabaena Pcc 7120 ◽  
Cyanobacterium Anabaena ◽  
Pcc 7120
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