What is calmodulin used for?

What is calmodulin used for?

Calmodulin plays an important role in excitation contraction (EC) coupling and the initiation of the cross-bridge cycling in smooth muscle, ultimately causing smooth muscle contraction. In order to activate contraction of smooth muscle, the head of the myosin light chain must be phosphorylated.

What is calmodulin in smooth muscle?

Calmodulin, the ubiquitous and multifunctional Ca(2+)-binding protein, mediates many of the regulatory effects of Ca2+, including the contractile state of smooth muscle. The interplay of such regulatory mechanisms provides the flexibility and adaptability required for the normal functioning of smooth-muscle tissues.

What is calmodulin and what role does it play in cell regulation?

Calmodulin is a Ca2+ binding protein present in all eukaryotic cells that serves as the primary intracellular receptor for Ca2+. This protein plays important regulatory roles in cell proligeration and is required at multiple points in the cell cycle.

Where is calmodulin found?

Calmodulin is located in the cytosol of the cell. It interacts with proteins elsewhere in the cell.

What is meant by calmodulin?

: a calcium-binding protein that mediates cellular metabolic processes (such as the contraction of muscle fibers) by regulating the activity of calcium-dependent enzymes.

How is calmodulin regulated?

Calmodulin-regulated enzymes can be divided into three classes according to their abilities to bind with and to be activated by calmodulin fragments: enzymes which are activated by the C-terminal fragment, such as the Ca2+-ATPase and phosphorylase kinase; enzymes which require both halves of the molecule, such as …

Is calmodulin a ligand?

Calmodulin (CaM) is a Ca2+ sensor and mediates Ca2+ signaling through binding of numerous target ligands. The binding of ligands by Ca2+-saturated CaM (holo-CaM) is governed by attractive hydrophobic and electrostatic interactions that are weakened under high pressure in aqueous solutions.

What is calmodulin physiology?

Calmodulin is a low molecular weight, acidic, calcium binding protein which mediates the Ca2+ regulation of a wide range of physiological processes throughout eukaryotic organisms. It is likely that the effects of such drugs result from their interaction with calmodulin.

Does skeletal muscle use calmodulin?

Recent studies have implicated calmodulin in the Ca2+ control of three enzymes in skeletal muscle: phosphorylase kinase, myosin light chain kinase and a protein kinase of the sarcoplasmic reticulum. It is likely that the effects of such drugs result from their interaction with calmodulin.

Is calmodulin a protein kinase?

Ca2+/calmodulin (Ca2+/CaM)-dependent protein kinases are important mediators of signal transduction events triggered by stimuli that increase intracellular levels of free [Ca2+].

What is the structure of calmodulin?

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.

Is calmodulin a GPCR?

Calmodulin (CaM) is a major effector for the intracellular actions of Ca2+ in nearly all cell types. G protein-coupled receptor (GPCR)-dependent activation of protein kinase A (PKA) led to phosphorylation of RCS at Ser55 and increased its binding to CaM.

Where does calmodulin make use of its calcium stores?

Calmodulin can also make use of the calcium stores in the endoplasmic reticulum, and the sarcoplasmic reticulum. Calmodulin can undergo post-translational modifications, such as phosphorylation, acetylation, methylation and proteolytic cleavage, each of which has potential to modulate its actions.

What is the role of calmodulin in the immune system?

Calmodulin mediates many crucial processes such as inflammation, metabolism, apoptosis, smooth muscle contraction, intracellular movement, short-term and long-term memory, and the immune response. Calcium participates in an intracellular signaling system by acting as a diffusible second messenger to the initial stimuli.

Are there any proteins that bind only to calmodulin?

“Canonical” targets of calmodulin, such as myosin light-chain kinases and CaMKII, bind only to the Ca 2+ -bound protein, whereas some proteins, such as NaV channels and IQ-motif proteins, also bind to calmodulin in the absence of Ca 2+.

What makes calmodulin an example of a cooperative protein?

Calcium binding by calmodulin exhibits considerable cooperativity, making calmodulin an unusual example of a monomeric (single-chain) cooperative-binding protein. Furthermore, target binding alters the binding affinity of calmodulin toward Ca 2+ ions, which allows for complex allosteric interplay between Ca 2+ and target binding interactions.