Calmodulin Protein

A Calmodulin Protein is a Eukariotic multifunctional intermediate Calcium-Binding Protein.

• AKA: CaM Modulator Protein.
• Context:
  • It is an abbreviation for CALcium-MODULated proteIN.
  • It includes Acidic Protein and 148 Amino Acids .
  • It is a ubiquitous Protein.
  • It can Bind To and Regulate many different Protein Targets, and thus affect many different Cellular Functions.
• Example(s):
  • Calmodulin 1(CALM1)
  • Calmodulin 2(CALM2)
  • Calmodulin 3(CALM3)
• Counter-Example(s):
  • Calmodulin-like 1 (CALML1)
  • Calmodulin-like 3 (CALML3)
  • Calmodulin-like 4 (CALML4)
  • Calmodulin-like 5 (CALML5)
  • Calmodulin-like 6 (CALML6)
• See: Phosphorylase Kinase, Bacillus Anthracis, Adenylate Cyclase, Apoptosis, Inflammation.

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References

2017

• (Wikipedia, 2017) ⇒ https://en.wikipedia.org/wiki/Calmodulin Retrieved:2017-5-28.
  • Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca²⁺, and the binding of Ca²⁺ is required for the activation of Calmodulin. Once bound to Ca²⁺, Calmodulin acts as part of a calcium signal transduction pathway by modifying its interactions with various target proteins such as kinases or phosphatases.

2012

• (G0, 2012) ⇒ Gene Ontology http://amigo.geneontology.org/cgi-bin/amigo/term-details.cgi?term=GO:0004629&session_id=5828amigo1240506945
  • Accession:GO:0005516
  • Ontology: molecular function
  • Synonyms :None
  • Definition
    • Interacting selectively with calmodulin, a calcium-binding protein with many roles, both in the calcium-bound and calcium-free states. [source: GOC:krc]

2003A

• (Dutta & Goodsell) ⇒ Shuchismita Dutta, David Goodsell doi:10.2210/rcsb_pdb/mom_2003_8
  • As its name suggests, calmodulin is a CALcium MODULated proteIN. It is abundant in the cytoplasm of all higher cells and has been highly conserved through evolution. Calmodulin acts as an intermediary protein that senses calcium levels and relays signals to various calcium-sensitive enzymes, ion channels and other proteins. Calmodulin is a small dumbbell-shaped protein composed of two globular domains connected together by a flexible linker. Each end binds to two calcium ions. PDB entry 3cln , shown here, has all four sites filled with calcium ions and the linker has formed a long alpha helix separating the two calcium-binding domains.

2003B

• (McDowall, 2003) ⇒ Jennifer McDowall (2003). “Calmodulin" http://www.ebi.ac.uk/interpro/potm/2003_3/Page_1.htm
  • Calmodulin (CaM) is a ubiquitous, calcium-binding protein that can bind to and regulate a multitude of different protein targets, thereby affecting many different cellular functions. CaM mediates processes such as inflammation, metabolism, apoptosis, muscle contraction, intracellular movement, short-term and long-term memory, nerve growth and the immune response. CaM is expressed in many cell types and can have different subcellular locations, including the cytoplasm, within organelles, or associated with the plasma or organelle membranes. Many of the proteins that CaM binds are unable to bind calcium themselves, and as such use CaM as a calcium sensor and signal transducer. CaM can also make use of the calcium stores in the endoplasmic reticulum, and the sarcoplasmic reticulum. CaM undergoes a conformational change upon binding to calcium, which enables it to bind to specific proteins for a specific response. CaM can bind up to four calcium ions, and can undergo post-translational modifications, such as phosphorylation, acetylation, methylation and proteolytic cleavage, each of which can potentially modulate its actions.

2000

• (Chin & Means, 2000) ⇒ Chin, D., & Means, A. R. (2000). Calmodulin: a prototypical calcium sensor. Trends in cell biology, 10(8), 322-328. PMID: 10884684
  • Abstract: Calmodulin is the best studied and prototypical example of the E-F-hand family of Ca2+-sensing proteins. Changes in intracellular Ca2+ concentration regulate calmodulin in three distinct ways. First, at the cellular level, by directing its subcellular distribution. Second, at the molecular level, by promoting different modes of association with many target proteins. Third, by directing a variety of conformational states in calmodulin that result in target-specific activation. The calmodulin-dependent regulation of protein kinases illustrates the potential mechanisms by which Ca2+-sensing proteins can recognize and generate affinity and specificity for effectors in a Ca2+-dependent manner.

1988

• (Babu et al., 1988) ⇒ Babu, Y. S., Bugg, C. E., & Cook, W. J. (1988). Structure of calmodulin refined at 2.2 Å resolution. Journal of molecular biology, 204(1), 191-204. PMID:3145979
  • ABSTRACT: The crystal structure of mammalian calmodulin has been refined at 2.2 A (1 A = 0.1 nm) resolution using a restrained least-squares method. The final crystallographic R-factor, based on 6685 reflections in the range 2.2 A less than or equal to d less than or equal to 5.0 A with intensities exceeding 2.5 sigma, is 0.175. Bond lengths and bond angles in the molecule have root-mean-square deviations from ideal values of 0.016 A and 1.7 degrees, respectively. The refined model includes residues 5 to 147, four Ca2+ and 69 water molecules per molecule of calmodulin. The electron density for residues 1 to 4 and 148 is poorly defined, and they are not included in the model. The molecule is shaped somewhat like a dumbbell, with an overall length of 65 A; the two lobes are connected by a seven-turn alpha-helix. Prominent secondary structural features include seven alpha-helices, four Ca2+-binding loops, and two short, double-stranded antiparallel beta-sheets between pairs of adjacent Ca2+-binding loops. The four Ca2+-binding domains in calmodulin have a typical EF hand conformation (helix-loop-helix) and are similar to those described in other Ca2+-binding proteins. The X-ray structure determination of calmodulin shows a large hydrophobic cleft in each half of the molecule. These hydrophobic regions probably represent the sites of interaction with many of the pharmacological agents known to bind to calmodulin.

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