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4aqr

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Revision as of 09:06, 6 March 2019

Crystal structure of calmodulin in complex with the regulatory domain of a plasma-membrane Ca2+-ATPase

Structural highlights

4aqr is a 3 chain structure with sequence from Arath. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Activity:	Calcium-transporting ATPase, with EC number 3.6.3.8
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[CALM7_ARATH] Calmodulin mediates the control of a large number of enzymes, ion channels and other proteins by Ca(2+). Among the enzymes to be stimulated by the calmodulin-Ca(2+) complex are a number of protein kinases and phosphatases. Activates MPK8 in vitro.^[1] [ACA8_ARATH] This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol out of the cell.

Publication Abstract from PubMed

Calcium ions (Ca(2+)) have an important role as secondary messengers in numerous signal transduction processes, and cells invest much energy in controlling and maintaining a steep gradient between intracellular ( approximately 0.1-micromolar) and extracellular ( approximately 2-millimolar) Ca(2+) concentrations. Calmodulin-stimulated calcium pumps, which include the plasma-membrane Ca(2+)-ATPases (PMCAs), are key regulators of intracellular Ca(2+) in eukaryotes. They contain a unique amino- or carboxy-terminal regulatory domain responsible for autoinhibition, and binding of calcium-loaded calmodulin to this domain releases autoinhibition and activates the pump. However, the structural basis for the activation mechanism is unknown and a key remaining question is how calmodulin-mediated PMCA regulation can cover both basal Ca(2+) levels in the nanomolar range as well as micromolar-range Ca(2+) transients generated by cell stimulation. Here we present an integrated study combining the determination of the high-resolution crystal structure of a PMCA regulatory-domain/calmodulin complex with in vivo characterization and biochemical, biophysical and bioinformatics data that provide mechanistic insights into a two-step PMCA activation mechanism mediated by calcium-loaded calmodulin. The structure shows the entire PMCA regulatory domain and reveals an unexpected 2:1 stoichiometry with two calcium-loaded calmodulin molecules binding to different sites on a long helix. A multifaceted characterization of the role of both sites leads to a general structural model for calmodulin-mediated regulation of PMCAs that allows stringent, highly responsive control of intracellular calcium in eukaryotes, making it possible to maintain a stable, basal level at a threshold Ca(2+) concentration, where steep activation occurs.

A bimodular mechanism of calcium control in eukaryotes.,Tidow H, Poulsen LR, Andreeva A, Knudsen M, Hein KL, Wiuf C, Palmgren MG, Nissen P Nature. 2012 Oct 21. doi: 10.1038/nature11539. PMID:23086147^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Takahashi F, Mizoguchi T, Yoshida R, Ichimura K, Shinozaki K. Calmodulin-dependent activation of MAP kinase for ROS homeostasis in Arabidopsis. Mol Cell. 2011 Mar 18;41(6):649-60. doi: 10.1016/j.molcel.2011.02.029. PMID:21419340 doi:http://dx.doi.org/10.1016/j.molcel.2011.02.029
↑ Tidow H, Poulsen LR, Andreeva A, Knudsen M, Hein KL, Wiuf C, Palmgren MG, Nissen P. A bimodular mechanism of calcium control in eukaryotes. Nature. 2012 Oct 21. doi: 10.1038/nature11539. PMID:23086147 doi:http://dx.doi.org/10.1038/nature11539

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/4aqr"

@@ Line 1: / Line 1: @@
 ==Crystal structure of calmodulin in complex with the regulatory domain of a plasma-membrane Ca2+-ATPase==
-<StructureSection load='4aqr' size='340' side='right' caption='[[4aqr]], [[Resolution|resolution]] 1.95&Aring;' scene=''>
+<StructureSection load='4aqr' size='340' side='right'caption='[[4aqr]], [[Resolution|resolution]] 1.95&Aring;' scene=''>
 == Structural highlights ==
 <table><tr><td colspan='2'>[[4aqr]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Arath Arath]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4AQR OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4AQR FirstGlance]. <br>

4aqr

From Proteopedia

Revision as of 09:06, 6 March 2019

Crystal structure of calmodulin in complex with the regulatory domain of a plasma-membrane Ca2+-ATPase

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

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