Related Experiment Video
Updated: Jul 18, 2026
07:51
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Sequence reversed peptide from CaMKK binds to calmodulin in reversible Ca2+ -dependent manner
Isaac T S Li1, K R Ranjith, Kevin Truong
1Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ont., Canada M5S 3G9.
Biochemical and Biophysical Research Communications
|December 13, 2006
Summary
Calmodulin (CaM) binds a novel synthetic peptide, revCKKp, by reversing a known CaM-binding sequence. This binding is Ca(2+)-dependent, demonstrating CaM
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Calmodulin (CaM) is a crucial calcium (Ca2+) signaling protein.
- CaM regulates over a hundred target proteins, highlighting its versatile function.
- CaM-dependent protein kinase kinase (CaMKK) contains a known CaM-binding peptide (CKKp).
Purpose of the Study:
- To investigate the binding versatility of Calmodulin (CaM).
- To characterize the interaction of a novel synthetic peptide, revCKKp, with CaM.
- To compare the binding of revCKKp with known CaM-binding peptides (CBPs).
Main Methods:
- Synthesis of a reversed peptide sequence (revCKKp) from CaMKK.
- Sequence comparison of revCKKp against the CaM target databank.
- Computational modeling of CaM-revCKKp interaction.
- Experimental validation of CaM-revCKKp binding using Ca(2+)-dependent assays.
Main Results:
- The synthetic peptide revCKKp does not resemble known CaM-binding peptide classes, except for its original sequence CKKp.
- Computational modeling suggests revCKKp binds CaM similarly to CKKp.
- Experimental data confirm that revCKKp binds CaM in a reversible, Ca(2+)-dependent manner.
Conclusions:
- Calmodulin's binding versatility extends to peptides with reversed sequences.
- The synthetic revCKKp peptide represents a novel CaM-binding motif.
- This finding contributes to understanding the molecular mechanisms of CaM target recognition.
Related Concept Videos
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:25cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
01:11IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:15Amplifying Signals via Second Messengers
Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
01:22Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...