Calmodulin 1 is a protein in humans that is encoded by the CALM1gene.[3]
Calmodulin[4] plays a role in calcium signal transduction pathways by regulating control of ion channels, enzymes, aquaporins, and other proteins. It functions as a calcium-binding protein that has been grouped into the EF-hand motif found in eukaryotic cells. Calmodulin plays a significant role in numerous cellular pathways and it acts as a calcium detector within the cells that interact with varied target proteins. Additionally, it simulates[5] the activation of over twenty amino acids which helps to control various physiological functions. It is also required for various regulatory roles in cell proliferation and throughout many points during the cell cycle.
Upon binding to targeted calcium (acts as ligand), calmodulin undergoes a change in shape that allows it to interact with multiple protein types including phosphatases, ion channels, and kinases. This conformational change is associated with undergoing various cellular processes: including muscle contraction, release of neurotransmitters into the bloodstream, and gene expression.
Function
Calmodulin 1 is the archetype of the family of calcium-modulated (calmodulin) proteins of which nearly 20 members have been found. They are identified by their occurrence in the cytosol or on membranes facing the cytosol and by a high affinity for calcium. Calmodulin contains 149 amino acids and has 4 calcium-binding EF hand motifs. Its functions include roles in growth and the cell cycle as well as in signal transduction and the synthesis and release of neurotransmitters.[6]
Gene expression
In humans, there are three genetic isoforms of calmodulin which are encoded by the homologous gene variations: CALM1, CALM2, and CALM3. Each three of the isoforms produce distinct, yet closely associated forms of calmodulin. At the nucleic acid level, the coding regions differ by a 15% between CALM1 and CALM2 and 13% between CALM2 and CALM3.[7]
Calmodulin I, abbreviated CALM1, is located on chromosome 14 of the human genome, and is one of the three isoforms of calmodulin. It’s found in all human tissues, although the expression varies depending on tissue type. There are high expression levels found in the brain, muscle, and blood.
Throughout the body, CALM1 plays a significant role in muscle contraction and relaxation in skeletal and smooth muscle. In heart muscle, CALM1 is vital for the regulation of calcium signaling to control efficient cardiac functioning. Calcium/calmodulin protein kinases (CaMKs)[8] work symbiotically to regulate calcium signaling throughout the body. CAMKII, the most prolific isoform, is found in cardiac tissue where it controls excitation-contraction coupling. Calmodulin I also plays an important role in the immune system through lymphocytes (white blood cells) where it contributes to immune cell function and activation. In bone tissue, Calmodulin I is associated with osteoblasts, osteoclasts, and osteocytes, by functioning in intracellular calcium signaling to ensure bone mineralization, resorption, and remodeling.
Calmodulin 1[7] can be expressed as one of two transcript types, which can be distinguished by length and tissue location. The major transcript is present in all tissues and is recorded as 1.7-kb in length. The minor transcript is either 4.1-kb or 4.4kb in length, and is only found in brain and skeletal muscle tissue. The difference in transcript lengths are caused by substitute cleavage and polyadenylation signals (APA), which permits the origination of different mRNA isoforms.
Pseudogenes
There are two known pseudogenes of Calmodulin 1, which are known as CALMIPI and CALMIP2. CALMPI was first discovered on chromosome 7, and the CALMPI2 was later identified on chromosome X. Experimentation shows both pseudogenes lack introns and have multiple mutations in their open reading frame, meaning that they cease all functions.
Mapping
Human[9] and rodent hybridized somatic cell panels show that complementary DNA for calmodulin I was localized to chromosome 14, with some cross hybridization activity on chromosome 7, and minor involvement on chromosome X.
Mutations of CALM1 CALM2 or CALM3 can lead to critical cardiac deficiencies including long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT).[18] Studies investigating calmodulin-associated diseases have discovered multiple proteins modified by calmodulin that determine the virulence of the mutations, including the cardiac L-type calcium channel (LTCC) Cav1.2, the sarcoplasmic reticulum calcium release channel, and the ryanodine receptor 2 (RyR2).
CALM1 disease mutations are often diagnosed in patients aged ten or younger, whereas CALM2 and CALM3 mutations typically develop in adulthood. Calmodulin functioning defects cause interference of vital calcium signaling events within the heart muscle which disrupts membrane ion channels. The disruptions in cell signaling can lead to potentially life-threatening cardiac disturbances in adolescence.
CPVT[20] is an inherited disorder that presents with episodes of syncope and/or sudden cardiac infarctions during exercise or extreme emotional episodes in humans without structural cardiac deformities. Mutations in the ryanodine-receptor 2 channel (RYR2) that causes calcium leakage from the sarcoplasmic reticulum have been proven to cause about half of dominantly inherited cases of CPVT.
It has been discovered that some individuals with CPVT have distinct mutations on the Calmodulin I gene. The mutations cause disruption in the proper functioning of the gene, which leads to abnormal calcium control in cardiac tissue cells. The calcium disturbance can trigger ventricular arrhythmias in reaction to blood vessel vasoconstriction, such as during periods of exercise or elevated stress.
Zhang M, Yuan T (1999). "Molecular mechanisms of calmodulin's functional versatility". Biochemistry and Cell Biology. 76 (2–3): 313–323. doi:10.1139/bcb-76-2-3-313. PMID9923700.
Gusev NB (October 2001). "Some properties of caldesmon and calponin and the participation of these proteins in regulation of smooth muscle contraction and cytoskeleton formation". Biochemistry. Biokhimiia. 66 (10): 1112–1121. doi:10.1023/A:1012480829618. PMID11736632. S2CID310781.
1cdl: TARGET ENZYME RECOGNITION BY CALMODULIN: 2.4 ANGSTROMS STRUCTURE OF A CALMODULIN-PEPTIDE COMPLEX
1cdm: MODULATION OF CALMODULIN PLASTICITY IN MOLECULAR RECOGNITION ON THE BASIS OF X-RAY STRUCTURES
1cfc: CALCIUM-FREE CALMODULIN
1cfd: CALCIUM-FREE CALMODULIN
1cff: NMR SOLUTION STRUCTURE OF A COMPLEX OF CALMODULIN WITH A BINDING PEPTIDE OF THE CA2+-PUMP
1ckk: CALMODULIN/RAT CA2+/CALMODULIN DEPENDENT PROTEIN KINASE FRAGMENT
1cll: CALMODULIN STRUCTURE REFINED AT 1.7 ANGSTROMS RESOLUTION
1cm1: MOTIONS OF CALMODULIN-SINGLE-CONFORMER REFINEMENT
1cm4: MOTIONS OF CALMODULIN-FOUR-CONFORMER REFINEMENT
1cmf: NMR SOLUTION STRUCTURE OF APO CALMODULIN CARBOXY-TERMINAL DOMAIN
1cmg: NMR SOLUTION STRUCTURE OF CALCIUM-LOADED CALMODULIN CARBOXY-TERMINAL DOMAIN
1ctr: DRUG BINDING BY CALMODULIN: CRYSTAL STRUCTURE OF A CALMODULIN-TRIFLUOPERAZINE COMPLEX
1deg: THE LINKER OF DES-GLU84 CALMODULIN IS BENT AS SEEN IN THE CRYSTAL STRUCTURE
1dmo: CALMODULIN, NMR, 30 STRUCTURES
1f70: REFINED SOLUTION STRUCTURE OF CALMODULIN N-TERMINAL DOMAIN
1f71: REFINED SOLUTION STRUCTURE OF CALMODULIN C-TERMINAL DOMAIN
1fw4: CRYSTAL STRUCTURE OF E. COLI FRAGMENT TR2C FROM CALMODULIN TO 1.7 A RESOLUTION
1g4y: 1.60 A CRYSTAL STRUCTURE OF THE GATING DOMAIN FROM SMALL CONDUCTANCE POTASSIUM CHANNEL COMPLEXED WITH CALCIUM-CALMODULIN
1iq5: Calmodulin/nematode CA2+/Calmodulin dependent kinase kinase fragment
1iwq: Crystal Structure of MARCKS calmodulin binding domain peptide complexed with Ca2+/Calmodulin
1j7o: Solution structure of Calcium-calmodulin N-terminal domain
1j7p: Solution structure of Calcium calmodulin C-terminal domain
1k90: Crystal structure of the adenylyl cyclase domain of anthrax edema factor (EF) in complex with calmodulin and 3' deoxy-ATP
1k93: Crystal structure of the adenylyl cyclase domain of anthrax edema factor (EF) in complex with calmodulin
1l7z: Crystal structure of Ca2+/Calmodulin complexed with myristoylated CAP-23/NAP-22 peptide
1lin: CALMODULIN COMPLEXED WITH TRIFLUOPERAZINE (1:4 COMPLEX)
1lvc: Crystal structure of the adenylyl cyclase domain of anthrax edema factor (EF) in complex with calmodulin and 2' deoxy, 3' anthraniloyl ATP
1mux: SOLUTION NMR STRUCTURE OF CALMODULIN/W-7 COMPLEX: THE BASIS OF DIVERSITY IN MOLECULAR RECOGNITION, 30 STRUCTURES
1mxe: Structure of the Complex of Calmodulin with the Target Sequence of CaMKI
1niw: Crystal structure of endothelial nitric oxide synthase peptide bound to calmodulin
1nwd: Solution Structure of Ca2+/Calmodulin bound to the C-terminal Domain of Petunia Glutamate Decarboxylase
1ooj: Structural genomics of Caenorhabditis elegans : Calmodulin
1pk0: Crystal Structure of the EF3-CaM complexed with PMEApp
1prw: Crystal structure of bovine brain Ca++ calmodulin in a compact form
1qiv: CALMODULIN COMPLEXED WITH N-(3,3,-DIPHENYLPROPYL)-N'-[1-R-(3,4-BIS-BUTOXYPHENYL)-ETHYL]-PROPYLENEDIAMINE (DPD), 1:2 COMPLEX
1qiw: CALMODULIN COMPLEXED WITH N-(3,3,-DIPHENYLPROPYL)-N'-[1-R-(3,4-BIS-BUTOXYPHENYL)-ETHYL]-PROPYLENEDIAMINE (DPD)
1qs7: The 1.8 angstrom structure of calmodulin rs20 peptide complex
1qtx: THE 1.65 ANGSTROM STRUCTURE OF CALMODULIN RS20 PEPTIDE COMPLEX
1qx5: Crystal structure of apoCalmodulin
1qx7: Crystal structure of apoCaM bound to the gating domain of small conductance Ca2+-activated potassium channel
1s26: Structure of Anthrax Edema Factor-Calmodulin-alpha,beta-methyleneadenosine 5'-triphosphate Complex Reveals an Alternative Mode of ATP Binding to the Catalytic Site
1sk6: Crystal structure of the adenylyl cyclase domain of anthrax edema factor (EF) in complex with calmodulin, 3',5' cyclic AMP (cAMP), and pyrophosphate
1sw8: Solution structure of the N-terminal domain of Human N60D calmodulin refined with paramagnetism based strategy
1sy9: Structure of calmodulin complexed with a fragment of the olfactory CNG channel
1up5: CHICKEN CALMODULIN
1vrk: THE 1.9 ANGSTROM STRUCTURE OF E84K-CALMODULIN RS20 PEPTIDE COMPLEX
1wrz: Calmodulin complexed with a peptide from a human death-associated protein kinase
1x02: Solution structure of stereo array isotope labeled (SAIL) calmodulin
1xa5: Structure of Calmodulin in complex with KAR-2, a bis-indol alkaloid
1xfu: Crystal structure of anthrax edema factor (EF) truncation mutant, EF-delta 64 in complex with calmodulin
1xfv: Crystal structure of anthrax edema factor (EF) in complex with calmodulin and 3' deoxy-ATP
1xfw: Crystal structure of anthrax edema factor (EF) in complex with calmodulin and 3'5' cyclic AMP (cAMP)
1xfx: Crystal structure of anthrax edema factor (EF) in complex with calmodulin in the presence of 10 millimolar exogenously added calcium chloride
1xfy: Crystal structure of anthrax edema factor (EF) in complex with calmodulin
1xfz: Crystal structure of anthrax edema factor (EF) in complex with calmodulin in the presence of 1 millimolar exogenously added calcium chloride
1y0v: Crystal structure of anthrax edema factor (EF) in complex with calmodulin and pyrophosphate
1y6w: Trapped intermediate of calmodulin
1yr5: 1.7-A structure of calmodulin bound to a peptide from DAP kinase
1yrt: Crystal Structure analysis of the adenylyl cyclaes catalytic domain of adenylyl cyclase toxin of Bordetella pertussis in presence of c-terminal calmodulin
1yru: Crystal Structure analysis of the adenylyl cyclaes catalytic domain of adenylyl cyclase toxin of Bordetella pertussis in presence of c-terminal calmodulin and 1mM calcium chloride
1zot: crystal structure analysis of the CyaA/C-Cam with PMEAPP
1zuz: Calmodulin in complex with a mutant peptide from human DRP-1 kinase
2bbm: SOLUTION STRUCTURE OF A CALMODULIN-TARGET PEPTIDE COMPLEX BY MULTIDIMENSIONAL NMR
2bbn: SOLUTION STRUCTURE OF A CALMODULIN-TARGET PEPTIDE COMPLEX BY MULTIDIMENSIONAL NMR
2bcx: Crystal structure of calmodulin in complex with a ryanodine receptor peptide
2be6: 2.0 A crystal structure of the CaV1.2 IQ domain-Ca/CaM complex
2bkh: MYOSIN VI NUCLEOTIDE-FREE (MDINSERT2) CRYSTAL STRUCTURE
2bki: MYOSIN VI NUCLEOTIDE-FREE (MDINSERT2-IQ) CRYSTAL STRUCTURE
2col: Crystal structure analysis of CyaA/C-Cam with Pyrophosphate
2dfs: 3-D structure of Myosin-V inhibited state
2f2o: Structure of calmodulin bound to a calcineurin peptide: a new way of making an old binding mode
2f2p: Structure of calmodulin bound to a calcineurin peptide: a new way of making an old binding mode
2f3y: Calmodulin/IQ domain complex
2f3z: Calmodulin/IQ-AA domain complex
2fot: Crystal structure of the complex between calmodulin and alphaII-spectrin
2hf5: The structure and function of a novel two-site calcium-binding fragment of calmodulin
2ix7: STRUCTURE OF APO-CALMODULIN BOUND TO UNCONVENTIONAL MYOSIN V
3cln: STRUCTURE OF CALMODULIN REFINED AT 2.2 ANGSTROMS RESOLUTION
4cln: STRUCTURE OF A RECOMBINANT CALMODULIN FROM DROSOPHILA MELANOGASTER REFINED AT 2.2-ANGSTROMS RESOLUTION