Regulation of intracellular free calcium concentration during heterocyst differentiation by HetR and NtcA in
            <i>Anabaena</i>
            sp. PCC 7120

Shi, Yunming; Zhao, Weixing; Zhang, Wei; Ye, Zi; Zhao, Jindong

doi:10.1073/pnas.0602839103

Cited by 48 publications

(36 citation statements)

References 47 publications

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“…To test the specificity of the DNA-binding activity of CalA, we used 4 other DNA fragments from the upstream regions of glnA, hetC, hetR and ntcA (denoted as U glnA , U hetC , U hetR and U ntcA , respectively) to compete with the fragment B2. glnA encodes glutamine synthetase (Fisher et al 1981), hetC encodes an ABC-cassette peptide transporter that affects cell division state transition during heterocyst differentiation (Khudyakov and Wolk 1997;Xu and Wolk 2001), hetR encodes the master regulator in heterocyst differentiation that shows both serine-type protease and transcriptional regulator activities (Zhou et al 1998;Huang et al 2004;Shi et al 2006), ntcA encodes a homo-dimeric transcriptional regulator that globally controls nitrogen metabolism ). These four DNA fragments have been shown to interact with the regulator NtcA or HetR Huang et al 2004;Laurent et al 2005;Muro-Pastor et al 1999).…”

Section: Specificity Of the Dna-binding Activity Of Calamentioning

confidence: 99%

CalA, a cyAbrB protein, binds to the upstream region of ftsZ and is down-regulated in heterocysts in Anabaena sp. PCC 7120

2010

Arch Microbiol

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A protein of cyAbrB family of regulators, Alr0946 (CalA), was identified by DNA affinity chromatography using DNA fragments from the promoter region of ftsZ in Anabaena/Nostoc sp. PCC 7120. Electrophoretic mobility shift assays showed that the protein could bind to upstream regions of ftsZ (as biotin-labeled DNA fragments) and that the binding was inhibited by the same DNA fragments and a fragment upstream of hetC but not by 3 fragments upstream of glnA, hetR or ntcA. Both transcriptional fusion with gfp (green fluorescence protein) and Western blot analysis indicated that the expression of calA was down-regulated in heterocysts relative to vegetative cells. An insertional mutant of calA could not be completely segregated. Over-expression of calA in Anabaena/ Nostoc caused no change in growth, heterocyst differentiation or expression of ftsZ. CalA as a DNA-binding protein is essential for the growth of Anabaena/Nostoc and may be required for the expression of ftsZ in vegetative cells.

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Section: Specificity Of the Dna-binding Activity Of Calamentioning

confidence: 99%

CalA, a cyAbrB protein, binds to the upstream region of ftsZ and is down-regulated in heterocysts in Anabaena sp. PCC 7120

2010

Arch Microbiol

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“…Also, the fact that the MNtcA and MP2 mutant strains of Synechococcus did not show the calcium signal implies that both proteins might be needed in conjunction with high levels of intracellular 2-OG to trigger the Ca 2+ transient; Shi et al (2006) have already found that the regulation of [Ca…”

Section: Discussionmentioning

confidence: 99%

Role of calcium in acclimation of the cyanobacterium Synechococcus elongatus PCC 7942 to nitrogen starvation

2009

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A Ca2+ signal is required for the process of heterocyst differentiation in the filamentous diazotrophic cyanobacterium Anabaena sp. PCC 7120. This paper presents evidence that a transient increase in intracellular free Ca2+ is also involved in acclimation to nitrogen starvation in the unicellular non-diazotrophic cyanobacterium Synechococcus elongatus PCC 7942. The Ca2+ transient was triggered in response to nitrogen step-down or the addition of 2-oxoglutarate (2-OG), or its analogues 2,2-difluoropentanedioic acid (DFPA) and 2-methylenepentanedioic acid (2-MPA), to cells growing with combined nitrogen, suggesting that an increase in intracellular 2-OG levels precedes the Ca2+ transient. The signalling protein PII and the transcriptional regulator NtcA appear to be needed to trigger the signal. Suppression of the Ca2+ transient by the intracellular Ca2+ chelator N,N′-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[N-[2-[(acetyloxy)methoxy]-2-oxoethyl]]-,bis[(acetyloxy)methyl] ester (BAPTA-AM) inhibited expression of the glnB and glnN genes, which are involved in acclimation to nitrogen starvation and transcriptionally activated by NtcA. BAPTA-AM treatment partially inhibited expression of the nblA gene, which is involved in phycobiliprotein degradation following nutrient starvation and is regulated by NtcA and NblR; in close agreement, BAPTA-AM treatment partially inhibited bleaching following nitrogen starvation. Taken together, the results presented here strongly suggest an involvement of a defined Ca2+ transient in acclimation of S. elongatus to nitrogen starvation through NtcA-dependent regulation.

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“…The figure was prepared by MOLMOL (25). C, surface electrostatic potential representation of Ca 2ϩ -free CcbP generated by GRASP2 (48 -buffering function was suggested previously based on functional studies (11). Because the Ca 2ϩ binding affinity of site I is in the micro-molar range, whereas the intracellular concentrations of free Ca 2ϩ in cyanobacteria are between 100 nM and 200 nM (11), the calcium ions bound by CcbP alone might not be a major pool of bound calcium under nitrogen-replete conditions.…”

Section: Anabaena Ccbp Represents a Novel Family Of Ca 2ϩ -Binding Prmentioning

confidence: 99%

“…strain PCC 7120 (Anabaena sp.) was identified as a major Ca 2ϩ -binding protein involved in Ca 2ϩ sequestration and the regulation of heterocyst differentiation (10,11). At the early stages of heterocyst differentiation, CcbP is degraded by a serine-type protease HetR, leading to a Ca 2ϩ release and subsequent differentiation processes (11).…”

mentioning

confidence: 99%

Structures of Anabaena Calcium-binding Protein CcbP

Hu¹,

Zhang²,

Shi³

et al. 2011

Journal of Biological Chemistry

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Regulation of intracellular free calcium concentration during heterocyst differentiation by HetR and NtcA in Anabaena sp. PCC 7120

Cited by 48 publications

References 47 publications

CalA, a cyAbrB protein, binds to the upstream region of ftsZ and is down-regulated in heterocysts in Anabaena sp. PCC 7120

CalA, a cyAbrB protein, binds to the upstream region of ftsZ and is down-regulated in heterocysts in Anabaena sp. PCC 7120

Role of calcium in acclimation of the cyanobacterium Synechococcus elongatus PCC 7942 to nitrogen starvation

Structures of Anabaena Calcium-binding Protein CcbP

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