CAMK

There are 2 common types of CAM Kinase proteins: specialized and multi-functional CAM kinases.

;Substrate-specific CAM Kinases: only have one target that they can phosphorylate, such as myosin light chain kinases. This group of proteins includes CAMK III. More on CAMKIII can be found following this link.

;Multi-functional CAM Kinases: have multiple targets they can phosphorylate and are found in processes including the secretion of neurotransmitters, metabolism of glycogen, and the regulation of various transcription factors. CAMK II is the main protein in this subset. More on CAMKII can be found following this link.

File:Psy161ST redrawn.svg

Once calcium concentrations in the cell rise, CAM kinases become saturated and bind the maximum of four calcium molecules. 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.{{cite journal | vauthors = Adams JA | title = Kinetic and catalytic mechanisms of protein kinases | journal = Chemical Reviews | volume = 101 | issue = 8 | pages = 2271–90 | date = August 2001 | pmid = 11749373 | doi = 10.1021/cr000230w }} 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.{{cite journal | vauthors = Hemmer W, McGlone M, Tsigelny I, Taylor SS | title = Role of the glycine triad in the ATP-binding site of cAMP-dependent protein kinase | journal = The Journal of Biological Chemistry | volume = 272 | issue = 27 | pages = 16946–54 | date = July 1997 | pmid = 9202006 | doi = 10.1074/jbc.272.27.16946 | s2cid = 33795382 | doi-access = free }} 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).File:CAMK I structure.png

All kinases have a common structure of a catalytic core including an ATP binding site along with a larger substrate binding site.{{cite journal | vauthors = Hanks SK | title = Genomic analysis of the eukaryotic protein kinase superfamily: a perspective | journal = Genome Biology | volume = 4 | issue = 5 | pages = 111 | date = 2003 | pmid = 12734000 | pmc = 156577 | doi = 10.1186/gb-2003-4-5-111 | doi-access = free }} The catalytic core is typically composed of β-strands with the substrate binding site composed of α-helices.{{cite journal | vauthors = Taylor SS, Yang J, Wu J, Haste NM, Radzio-Andzelm E, Anand G | title = PKA: a portrait of protein kinase dynamics | journal = Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics | volume = 1697 | issue = 1–2 | pages = 259–69 | date = March 2004 | pmid = 15023366 | doi = 10.1016/j.bbapap.2003.11.029 }} 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.{{cite journal | vauthors = Hudmon A, Schulman H | title = Neuronal CA2+/calmodulin-dependent protein kinase II: the role of structure and autoregulation in cellular function | journal = Annual Review of Biochemistry | volume = 71 | issue = 1 | pages = 473–510 | date = 2002-06-01 | pmid = 12045104 | doi = 10.1146/annurev.biochem.71.110601.135410 }}

;CAMK I: as shown in Figure 2, has a double-lobed structure, consisting of a catalytic, substrate-binding domain and an autoinhibitory domain. For the autoinhibitory domain to become functional, it must cause the protein to conform in such a way that this domain completely blocks the substrate domain from taking in new targets. Figure 2 goes into detail showing the structure and domains of CAMK I.

;CAMK II: has a variety of different forms, with CAMK 2A being the most common, as shown in Figure 3. CAMK 2A has a ring-like crystalline structure, composed of smaller functional groups. These groups allow for the CaM-dependent phosphorylation of targets, but also allows the structure to autophosphorylate itself and become CaM-independent,{{Cite web|url=https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=ShowDetailView&TermToSearch=815|title=CAMK2A calcium/calmodulin dependent protein kinase II alpha [Homo sapiens (human)] - Gene - NCBI|website=www.ncbi.nlm.nih.gov|access-date=2020-03-20}} as seen in Figure 1. This means once the CAMK 2A protein is initially activated by calcium or calmodulin, it can, in turn, further activate itself, so it doesn't become inactive even when it is without calcium or calmodulin. File:PDB 1hkx EBI.jpg

Members of the CAMK enzyme class include, but are not limited to:

• CAMKI
• CAMKIα (CAMK1)
• CAMKIβ (PNCK)
• CAMKIδ
• CAMKIγ (CAMK1G)
• CAMKII
• CAMKIIα
• CAMKIIβ
• CAMKIIδ
• CAMKIIγ
• CAMKIII
• CAMKIV
• CAMKV CaM kinase like vesicle associated
• SCAMK
• Ca2+/calmodulin-dependent protein kinase kinase
• CAMKK1
• CAMKK2

Pseudokinases are pseudoenzymes, proteins that resemble enzymes structurally, but lack catalytic activity.

Some of these pseudokinases that are related to the CAMK family include:

• Tribbles subfamily
• TRIB1
• TRIB2
• TRIB3

{{reflist}}

{{Intracellular signaling peptides and proteins}}

{{Serine/threonine-specific protein kinases}}

{{Enzymes}}

{{Portal bar|Biology|border=no}}

Category:EC 2.7.11