Evidence for the possible involvement of calmodulin in regulation of steady state levels of Hsp90 family members (Hsp87 and Hsp85) in response to heat shock in sorghum

Virdi, Amardeep Singh; Pareek, Ashwani; Singh, Prabhjeet

doi:10.4161/psb.6.3.13867

Cited by 14 publications

(11 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CaM is one of the best-characterized Ca 2+ -sensors, which after binding to Ca 2+ undergoes conformation change and regulates the activity of diverse range of CaM-binding proteins (CaMBPs). Interaction of CaM with its target proteins can be Ca 2+ -dependent, as has been observed for various plant proteins including kinases [ 39 , 65 ], transcription activators [ 66 ] and heat shock protein 90 [ 49 , 67 ], or Ca 2+ -independent, as was reported for neuromodulin and neurogranin [ 68 ]. Employing protein microarray and co-immunoprecipitation studies, Popescue et al [ 38 ] provided evidence for the interaction of AtCyp19-3 with CaM although the dependency of this interaction on Ca 2+ was not investigated.…”

Section: Resultsmentioning

confidence: 90%

Characterization of Peptidyl-Prolyl Cis-Trans Isomerase- and Calmodulin-Binding Activity of a Cytosolic Arabidopsis thaliana Cyclophilin AtCyp19-3

Kaur

Singh

et al. 2015

PLoS ONE

Self Cite

View full text Add to dashboard Cite

Cyclophilins, which bind to immunosuppressant cyclosporin A (CsA), are ubiquitous proteins and constitute a multigene family in higher organisms. Several members of this family are reported to catalyze cis-trans isomerisation of the peptidyl-prolyl bond, which is a rate limiting step in protein folding. The physiological role of these proteins in plants, with few exceptions, is still a matter of speculation. Although Arabidopsis genome is predicted to contain 35 cyclophilin genes, biochemical characterization, imperative for understanding their cellular function(s), has been carried only for few of the members. The present study reports the biochemical characterization of an Arabidopsis cyclophilin, AtCyp19-3, which demonstrated that this protein is enzymatically active and possesses peptidyl-prolyl cis-trans isomerase (PPIase) activity that is specifically inhibited by CsA with an inhibition constant (Ki) of 18.75 nM. The PPIase activity of AtCyp19-3 was also sensitive to Cu2+, which covalently reacts with the sulfhydryl groups, implying redox regulation. Further, using calmodulin (CaM) gel overlay assays it was demonstrated that in vitro interaction of AtCyp19-3 with CaM is Ca2+-dependent, and CaM-binding domain is localized to 35–70 amino acid residues in the N-terminus. Bimolecular fluorescence complementation assays showed that AtCyp19-3 interacts with CaM in vivo also, thus, validating the in vitro observations. However, the PPIase activity of the Arabidopsis cyclophilin was not affected by CaM. The implications of these findings are discussed in the context of Ca2+ signaling and cyclophilin activity in Arabidopsis.

show abstract

Section: Resultsmentioning

confidence: 90%

Characterization of Peptidyl-Prolyl Cis-Trans Isomerase- and Calmodulin-Binding Activity of a Cytosolic Arabidopsis thaliana Cyclophilin AtCyp19-3

Kaur

Singh

et al. 2015

PLoS ONE

Self Cite

View full text Add to dashboard Cite

show abstract

“…Significant (P \ 0.05) up-regulation of AmHsp90 transcripts was detected during the late stage of cold and drought treatments, and during the whole process of salt stress. Although expression of HSP90 genes had shown to be enhanced by elevated temperature in many plant species (Frank et al 2009;Virdi et al 2011), AmHsp90 responded less to heat treatment than to cold, drought and salt, suggesting that AmHsp90 may be a heat shock protein of a new type. These results indicated that the best reference genes chosen by geNorm or NormFinder under each treatment may be reliable.…”

Section: Validation Of Reference Genesmentioning

confidence: 90%

Reference gene selection for qPCR in Ammopiptanthus mongolicus under abiotic stresses and expression analysis of seven ROS-scavenging enzyme genes

et al. 2012

View full text Add to dashboard Cite

Ammopiptanthus mongolicus, the only evergreen broadleaf shrub endemic to the northwest desert of China, is a valuable species for plant abiotic stress research. No report has so far described the selection of reference genes to get stringent normalization for qPCR in A. mongolicus. This work identified reliable reference genes for normalization of qPCR data in A. mongolicus under abiotic stresses from 14 reference gene candidates (UBQ, Tub1, Tub2, Abc1, Ubc1, Ubc2, Ubc4, Ubc5, eIF1, eIF2, eIF3, eIF4, EF1, EF2), and used the most suitable combination of reference genes to normalize the expression profiles of seven ROS-scavenging enzyme genes (AmSOD, AmAPX, AmGPX, AmCAT, AmGLR, AmPrx, and AmTrx). We set a series of 22 experimental samples covering the control and different time points under cold, dry, salt, and heat stresses. According to geNorm and NormFinder, the combination of eIF1 and eIF3 was best for accurate normalization across all the treatments, confirmed by normalizing qPCR data with AmHsp90. In contrast, these data show that Tub1, Abc1, and EF1 are not suitable reference gene candidates. After being normalized against eIF1 and eIF3, the seven ROS-scavenging enzyme genes exhibited differentially up- or down-regulated expression patterns. AmSOD and AmGPX were up-regulated by all four treatments, indicating that they may participate in an anti-oxidative mechanism under abiotic stresses in A. mongolicus. AmCAT exhibited a much higher expression level than AmAPX, AmPrx, and AmGPX, suggesting a principle role in detoxifying excessive H₂O₂. AmSOD, AmGPX and AmAPX showing the most abundant transcripts under heat, AmCAT and AmGLR under drought, and AmPrx under salt, were observed. Expression patterns of the seven ROS-scavenging enzyme genes suggest different antioxidant protection roles of these genes under abiotic stresses. These results are valuable for future research on gene expression and abiotic stress tolerance in A. mongolicus.

show abstract

“…The expression of HSP genes is repressed in the absence of heat stress which is proposed to be due to interaction of heat shock factors (HSFs) with HSP90 (Zou et al, 1998 ) and/or HSP70 (Sun et al, 2000 ). The Ca 2+ -CaM and the denatured proteins, produced as a result of unfolded protein response (UPR) due to reactive oxygen species (ROS)-mediated oxidation, bind to HSP70/HSP90, thereby releasing the HSFs (Yamada and Nishimura, 2008 ; Virdi et al, 2009 , 2011 ). H 2 O 2 acts upstream of NO which regulates the expression of AtCaM3 through modulation of the binding of HSF to the heat shock elements (HSEs; Wang et al, 2014a ).…”

Section: Regulation Of Heat Shock Response Through Ca 2+ mentioning

confidence: 99%

“…Heat shock response in plants also appears to be regulated by CaM through interaction with HSPs such as HSP70 (Sun et al, 2000 ) and HSP90 (Virdi et al, 2009 , 2011 ). The HSP90 (Zou et al, 1998 ) and HSP70 (Sun et al, 2000 ) have been proposed to act as repressors of HSFs in the absence of heat stress.…”

Section: Regulation Of Heat Shock Response Through Ca 2+ mentioning

confidence: 99%

“…Studies in our lab demonstrated that sorghum HSP90, SbHSP90, binds to CaM in a Ca 2+ -dependent manner (Virdi et al, 2009 ). It was also observed that the steady state levels of SbHSP90 are regulated through Ca 2+ /CaM pathway since the heat stress-induced increase in HSP90 levels was abrogated in the presence of exogenous Ca 2+ -channel blockers and CaM-antagonists (Virdi et al, 2011 ). On the basis of these observations, we proposed that in addition to denatured proteins, as suggested by Yamada and Nishimura ( 2008 ), dissociation of HSP90-HSF complex might also involve interaction of Ca 2+ -CaM with HSP90, thereby releasing the HSF to activate the transcription of HSP genes (Virdi et al, 2011 ).…”

Section: Regulation Of Heat Shock Response Through Ca 2+ mentioning

confidence: 99%

See 1 more Smart Citation

Abiotic stress responses in plants: roles of calmodulin-regulated proteins

2015

Self Cite

View full text Add to dashboard Cite

Intracellular changes in calcium ions (Ca2+) in response to different biotic and abiotic stimuli are detected by various sensor proteins in the plant cell. Calmodulin (CaM) is one of the most extensively studied Ca2+-sensing proteins and has been shown to be involved in transduction of Ca2+ signals. After interacting with Ca2+, CaM undergoes conformational change and influences the activities of a diverse range of CaM-binding proteins. A number of CaM-binding proteins have also been implicated in stress responses in plants, highlighting the central role played by CaM in adaptation to adverse environmental conditions. Stress adaptation in plants is a highly complex and multigenic response. Identification and characterization of CaM-modulated proteins in relation to different abiotic stresses could, therefore, prove to be essential for a deeper understanding of the molecular mechanisms involved in abiotic stress tolerance in plants. Various studies have revealed involvement of CaM in regulation of metal ions uptake, generation of reactive oxygen species and modulation of transcription factors such as CAMTA3, GTL1, and WRKY39. Activities of several kinases and phosphatases have also been shown to be modulated by CaM, thus providing further versatility to stress-associated signal transduction pathways. The results obtained from contemporary studies are consistent with the proposed role of CaM as an integrator of different stress signaling pathways, which allows plants to maintain homeostasis between different cellular processes. In this review, we have attempted to present the current state of understanding of the role of CaM in modulating different stress-regulated proteins and its implications in augmenting abiotic stress tolerance in plants.

show abstract

Evidence for the possible involvement of calmodulin in regulation of steady state levels of Hsp90 family members (Hsp87 and Hsp85) in response to heat shock in sorghum

Cited by 14 publications

References 39 publications

Characterization of Peptidyl-Prolyl Cis-Trans Isomerase- and Calmodulin-Binding Activity of a Cytosolic Arabidopsis thaliana Cyclophilin AtCyp19-3

Characterization of Peptidyl-Prolyl Cis-Trans Isomerase- and Calmodulin-Binding Activity of a Cytosolic Arabidopsis thaliana Cyclophilin AtCyp19-3

Reference gene selection for qPCR in Ammopiptanthus mongolicus under abiotic stresses and expression analysis of seven ROS-scavenging enzyme genes

Abiotic stress responses in plants: roles of calmodulin-regulated proteins

Contact Info

Product

Resources

About