There are 2 common types of CAM Kinase proteins: specialized and multi-functional CAM kinases.
Once calcium concentrations in the cell rise, CAM kinases become saturated and bind the maximum of four calcium molecules.4 This calcium saturation activates the kinase and allows it to undergo a conformational change which permits the kinase to bind to its phosphorylation target sites. CAMK removes a phosphate group from ATP, most typically using a Mg2+ ion, and adds it to the CAM protein, rendering it active.5 The CAM Kinase contains a highly concentrated glycine loop where the gamma phosphate from the donor ATP molecule is easily able to bind to the enzyme which then utilizes the metal ion to facilitate a smooth phosphate transfer to the target protein.6 This phosphate transfer then activates the kinase's target and completes the phosphorylation cycle.
Figure 1 shows how the presence of calcium or calmodulin allows for the activation of CAM kinases (CAMK II).
All kinases have a common structure of a catalytic core including an ATP binding site along with a larger substrate binding site.7 The catalytic core is typically composed of β-strands with the substrate binding site composed of α-helices.8 Most all CAM kinases includes a variety of domains, including: a catalytic domain, a regulatory domain, an association domain, and a calcium/calmodulin binding domain.9
Members of the CAMK enzyme class include, but are not limited to:
Pseudokinases are pseudoenzymes, proteins that resemble enzymes structurally, but lack catalytic activity.
Some of these pseudokinases that are related to the CAMK family include:
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"CAMK2A calcium/calmodulin dependent protein kinase II alpha [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2020-03-20. https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=ShowDetailView&TermToSearch=815 ↩