Crystal structure of <i>Arabidopsis thaliana</i> calmodulin7 and insight into its mode of <scp>DNA</scp> binding

Kumar, Sanjeev; Mazumder, Mohit; Gupta, Nisha; Chattopadhyay, Sudip; Gourinath, S.

doi:10.1002/1873-3468.12349

Cited by 28 publications

(10 citation statements)

References 45 publications

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“…Arabidopsis calmodulin 7 contains a single Cys in its second EF hand, which corresponds to C384 in TPK2. The oxygen of the peptide chain of Cys forms a coordinated bond with Ca 2+ [21]. A similar interaction of the free Cys is also observed in guanylyl cyclase activator protein 1 belonging to the calmodulin superfamily [22].…”

Section: Discussionsupporting

confidence: 52%

“…EF1 in TPK2 contains two Cys separated by two amino acids (Figure 3(a)), a unique feature that is not present in the EF hands of TPK1, 3, 4 and 5, KCO3, the TPK homologs. Some calmodulin homologs possess a single Cys that corresponds to C384 in TPK2, but lack the second Cys corresponding to C381 [20][21][22]. The conserved Cys participates in the interaction with Ca 2+ in calmodulin [21].…”

Section: Role Of Cys In Ef2 Of Tpk2mentioning

confidence: 99%

“…Some calmodulin homologs possess a single Cys that corresponds to C384 in TPK2, but lack the second Cys corresponding to C381 [20][21][22]. The conserved Cys participates in the interaction with Ca 2+ in calmodulin [21]. We hypothesized that the two adjacent cysteine residues in TPK2 may form disulfide bonds, leading to a conformational change of the EF hand and resulting in regulation of Ca 2+ binding ability.…”

Section: Role Of Cys In Ef2 Of Tpk2mentioning

confidence: 99%

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Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K⁺ channel function

et al. 2020

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Arabidopsis thaliana contains five tandem-pore domain potassium channels, TPK1-TPK5 and the related one-pore domain potassium channel, KCO3. Although KCO3 is unlikely to be an active channel, it still has a physiological role in plant cells. TPK2 is most similar to KCO3 and both are localized to the tonoplast. However, their function remains poorly understood. Here, taking advantage of the similarities between TPK2 and KCO3, we evaluated Ca 2+ binding to the EF hands in TPK2, and the elements of KCO3 required for K + channel activity. Presence of both EFhand motifs in TPK2 resulted in Ca 2+ binding, but EF1 or EF2 alone failed to interact with Ca 2+ . The EF hands were not required for K + transport activity. EF1 contains two cysteines separated by two amino acids. Replacement of both cysteines with serines in TPK2 increased Ca 2+ binding. We generated a two-pore domain chimeric K + channel by replacing the missing pore region in KCO3 with a pore domain of TPK2. Alternatively, we generated two versions of simple one-pore domain K + channels by removal of an extra region from KCO3. The chimera and one of the simple onepore variants were functional channels. This strongly suggests that KCO3 is not a pseudogene and KCO3 retains components required for the formation of a functional K + channel and oligomerization. Our results contribute to our understanding of the structural properties required for K + channel activity.

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Section: Discussionsupporting

confidence: 52%

Section: Role Of Cys In Ef2 Of Tpk2mentioning

confidence: 99%

Section: Role Of Cys In Ef2 Of Tpk2mentioning

confidence: 99%

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Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K⁺ channel function

et al. 2020

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“… The canonical EF-hand. Ca 2+ coordination in the Ca 2+ binding loop-4 of Arabidopsis CaM7 (PDB CODE: 5A2H) [ 3 ]. W, water molecule.…”

Section: Figurementioning

confidence: 99%

Towards Understanding Plant Calcium Signaling through Calmodulin-Like Proteins: A Biochemical and Structural Perspective

Verde

Dominici

Astegno

2018

IJMS

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Ca2+ ions play a key role in a wide variety of environmental responses and developmental processes in plants, and several protein families with Ca2+-binding domains have evolved to meet these needs, including calmodulin (CaM) and calmodulin-like proteins (CMLs). These proteins have no catalytic activity, but rather act as sensor relays that regulate downstream targets. While CaM is well-studied, CMLs remain poorly characterized at both the structural and functional levels, even if they are the largest class of Ca2+ sensors in plants. The major structural theme in CMLs consists of EF-hands, and variations in these domains are predicted to significantly contribute to the functional versatility of CMLs. Herein, we focus on recent advances in understanding the features of CMLs from biochemical and structural points of view. The analysis of the metal binding and structural properties of CMLs can provide valuable insight into how such a vast array of CML proteins can coexist, with no apparent functional redundancy, and how these proteins contribute to cellular signaling while maintaining properties that are distinct from CaM and other Ca2+ sensors. An overview of the principal techniques used to study the biochemical properties of these interesting Ca2+ sensors is also presented.

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“…One of the prerequisites for proteasomal degradation is the presence of an unstructured region in the substrate (Erales & Coffino, 2014;Jariel-Encontre, Bossis, & Piechaczyk, 2008). Structural analysis and interaction studies of CaM demonstrated that it displays high conformational flexibility and itself undergoes from disorder to order transition (Barbato, Ikura, Kay, Pastor, & Bax, 1992;Kumar, Mazumder, Gupta, Chattopadhyay, & Gourinath, 2016;Radivojac et al, 2006;Tidow & Nissen, 2013;Wall, Clarage, & Phillips, 1997). In this case, the CaM may take up favorable geometry to facilitate interaction and translocation into the proteasome.…”

Section: Discussionmentioning

confidence: 99%

COP1 regulates the stability of CAM7 to promote photomorphogenic growth

et al. 2019

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The unique member of the calmodulin gene family, Calmodulin7 ( CAM 7), plays a crucial role as transcriptional regulator to promote Arabidopsis seedling development. CAM 7 regulates the expression of HY 5 , which is intimately involved in the promotion of photomorphogenic growth and light‐regulated gene expression. COP 1 ubiquitin ligase suppresses photomorphogenesis by degrading multiple photomorphogenesis promoting factors including HY 5 in darkness. Genetic interaction studies, in this report, reveal that CAM 7 and COP 1 co‐ordinately work to promote photomorphogenic growth and light‐regulated gene expression at lower intensity of light. CAM 7 physically interacts with COP 1 in the nucleus. Further, in vivo study suggests that CAM 7 and COP 1 interaction is light intensity dependent. We have also shown that functional COP 1 is required for optimum accumulation of CAM 7 at lower fluences of light. Taken together, this study demonstrates the coordinated function of CAM 7 and COP 1 in Arabidopsis seedling development.

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Crystal structure of Arabidopsis thaliana calmodulin7 and insight into its mode of DNA binding

Cited by 28 publications

References 45 publications

Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K⁺ channel function

Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K⁺ channel function

Towards Understanding Plant Calcium Signaling through Calmodulin-Like Proteins: A Biochemical and Structural Perspective

COP1 regulates the stability of CAM7 to promote photomorphogenic growth

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Crystal structure of Arabidopsis thaliana calmodulin7 and insight into its mode of DNA binding

Cited by 28 publications

References 45 publications

Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K+ channel function

Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K+ channel function

Towards Understanding Plant Calcium Signaling through Calmodulin-Like Proteins: A Biochemical and Structural Perspective

COP1 regulates the stability of CAM7 to promote photomorphogenic growth

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Product

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Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K⁺ channel function

Analysis of Arabidopsis TPK2 and KCO3 reveals structural properties required for K⁺ channel function