Ca(2+)/calmodulin-dependent protein kinase IV expression in epithelial ovarian cancer

The Calcium/Calmodulin-Dependent Kinases II and IV as Therapeutic Targets in Neurodegenerative and Neuropsychiatric Disorders

CaMKII and CaMKIV are calcium/calmodulin-dependent kinases playing a rudimentary role in many regulatory processes in the organism. These kinases attract increasing interest due to their involvement primarily in memory and plasticity and various cellular functions. Although CaMKII and CaMKIV are mostly recognized as the important cogs in a memory machine, little is known about their effect on mood and role in neuropsychiatric diseases etiology. Here, we aimed to review the structure and functions of CaMKII and CaMKIV, as well as how these kinases modulate the animals’ behavior to promote antidepressant-like, anxiolytic-like, and procognitive effects. The review will help in the understanding of the roles of the above kinases in the selected neurodegenerative and neuropsychiatric disorders, and this knowledge can be used in future drug design.

Hesperidin-CAMKIV interaction and its impact on cell proliferation and apoptosis in the human hepatic carcinoma and neuroblastoma cells

Calcium/calmodulin-dependent protein kinase IV (CAMKIV) is a key regulatory molecule of cell signaling, and thereby controls its growth and proliferation, including expression of certain genes. The overexpression of CAMKIV is directly associated with the development of different types of cancers. Hesperidin is abundantly found in citrus fruits and exhibits wide range of pharmacological activities including anti-inflammatory, antibacterial and anticancerous effects. We have investigated binding mechanism of hesperidin with the CAMKIV using molecular docking methods followed by fluorescence quenching and isothermal titration calorimetric assays. An appreciable binding affinity of hesperidin was observed with CAMKIV during fluorescence quenching and isothermal titration calorimetric studies. Efficacy of hesperidin to inhibit the growth of human hepatic carcinoma (HepG2) and neuroblastoma (SH-SY5Y) cancer cell lines were investigated. Hesperidin has significantly reduced the proliferation of HepG2 and SH-SY5Y cells and induces apoptosis by activating the caspase-3-dependent intrinsic pathway through the upregulation of proapoptotic Bax protein. Hesperidin treatment reduces the mitochondrial membrane potential of HepG2 and SH-SY5Y cells. All these observations clearly anticipated hesperidin a potent inhibitor of CAMKIV which may be further exploited a newer therapeutic approach for the management of different cancer types.

High throughput screening, docking, and molecular dynamics studies to identify potential inhibitors of human calcium/calmodulin-dependent protein kinase IV

Calcium/calmodulin-dependent protein kinase IV (CAMKIV) is associated with many diseases including cancer and neurodegenerative disorders and thus being considered as a potential drug target. Here, we have employed the knowledge of three-dimensional structure of CAMKIV to identify new inhibitors for possible therapeutic intervention. We have employed virtual high throughput screening of 12,500 natural compounds of Zinc database to screen the best possible inhibitors of CAMKIV. Subsequently, 40 compounds which showed significant docking scores (-11.6 to -10.0 kcal/mol) were selected and further filtered through Lipinski rule and drug likeness parameter to get best inhibitors of CAMKIV. Docking results are indicating that ligands are binding to the hydrophobic cavity of the kinase domain of CAMKIV and forming a significant number of non-covalent interactions. Four compounds, ZINC02098378, ZINC12866674, ZINC04293413, and ZINC13403020, showing excellent binding affinity and drug likeness were subjected to molecular dynamics simulation to evaluate their mechanism of interaction and stability of protein-ligand complex. Our observations clearly suggesting that these selected ligands may be further employed for therapeutic intervention to address CAMKIV associated diseases. Communicated by Ramaswamy H. Sarma.

Evidence of vanillin binding to CAMKIV explains the anti-cancer mechanism in human hepatic carcinoma and neuroblastoma cells

Human calcium/calmodulin-dependent protein kinase IV (CAMKIV) is a member of Ser/Thr kinase family, and is associated with different types of cancer and neurodegenerative diseases. Vanillin is a natural compound, a primary component of the extract of the vanilla bean which possesses varieties of pharmacological features including anti-oxidant, anti-inflammatory, anti-bacterial and anti-tumor. Here, we have investigated the binding mechanism and affinity of vanillin to the CAMKIV which is being considered as a potential drug target for cancer and neurodegenerative diseases. We found that vanillin binds strongly to the active site cavity of CAMKIV and stabilized by a large number of non-covalent interactions. We explored the utility of vanillin as anti-cancer agent and found that it inhibits the proliferation of human hepatocyte carcinoma (HepG2) and neuroblastoma (SH-SY5Y) cells in a dose-dependent manner. Furthermore, vanillin treatment resulted into the significant reduction in the mitochondrial membrane depolarization and ROS production that eventually leads to apoptosis in HepG2 and SH-SY5Y cancer cells. These findings may offer a novel therapeutic approach by targeting the CAMKIV using natural product and its derivative with a minimal side effect.

Urea-induced denaturation of human calcium/calmodulin-dependent protein kinase IV: a combined spectroscopic and MD simulation studies

Calcium/calmodulin-dependent protein kinase IV (CaMKIV) is a multifunctional enzyme which belongs to the Ser/Thr kinase family. CaMKIV plays important role in varieties of biological processes such as gene expression regulation, memory consolidation, bone growth, T-cell maturation, sperm motility, regulation of microtubule dynamics, cell-cycle progression, and apoptosis. To measure stability parameters, urea-induced denaturation of CaMKIV was carried out at pH 7.4 and 25°C, using three different probes, namely far-UV CD, near-UV absorption, and tryptophan fluorescence. A coincidence of normalized denaturation curves of these optical properties suggests that urea-induced denaturation is a two-state process. Analysis of these denaturation curves gave values of 4.20 ± 0.12 kcal mol^-1, 2.95 ± 0.15 M, and 1.42 ± 0.06 kcal mol^-1 M^-1 for [Formula: see text] (Gibbs free energy change (ΔG_D) in the absence of urea), C_m (molar urea concentration ([urea]) at the midpoint of the denaturation curve), and m (=∂ΔG_D/∂[urea]), respectively. All these experimental observations have been fully supported by 30 ns molecular dynamics simulation studies.

Effect of pH on the structure, function, and stability of human calcium/calmodulin-dependent protein kinase IV: combined spectroscopic and MD simulation studies

Human calcium/calmodulin-dependent protein kinase IV (CAMKIV) is a member of Ser/Thr protein kinase family. It is regulated by the calcium-calmodulin dependent signal through a secondary messenger, Ca(2+), which leads to the activation of its autoinhibited form. The over-expression and mutation in CAMKIV as well as change in Ca(2+) concentration is often associated with numerous neurodegenerative diseases and cancers. We have successfully cloned, expressed, and purified a functionally active kinase domain of human CAMKIV. To observe the effect of different pH conditions on the structural and functional properties of CAMKIV, we have used spectroscopic techniques such as circular diachroism (CD) absorbance and fluorescence. We have observed that within the pH range 5.0-11.5, CAMKIV maintained both its secondary and tertiary structures, along with its function, whereas significant aggregation was observed at acidic pH (2.0-4.5). We have also performed ATPase activity assays under different pH conditions and found a significant correlation between the structure and enzymatic activities of CAMKIV. In-silico validations were further carried out by modeling the 3-dimensional structure of CAMKIV and then subjecting it to molecular dynamics (MD) simulations to understand its conformational behavior in explicit water conditions. A strong correlation between spectroscopic observations and the output of molecular dynamics simulation was observed for CAMKIV.

Calcium/calmodulin-dependent protein kinase IV: A multifunctional enzyme and potential therapeutic target

The calcium/calmodulin-dependent protein kinase IV (CAMKIV) belongs to the serine/threonine protein kinase family, and is primarily involved in transcriptional regulation in lymphocytes, neurons and male germ cells. CAMKIV operates the signaling cascade and regulates activity of several transcription activators by phosphorylation, which in turn plays pivotal roles in immune response, inflammation and memory consolidation. In this review, we tried to focus on different aspects of CAMKIV to understand the significance of this protein in the biological system. This enzyme is associated with varieties of disorders such as cerebral hypoxia, azoospermia, endometrial and ovarian cancer, systemic lupus, etc., and hence it is considered as a potential therapeutic target. Structure of CAMKIV is comprised of five distinct domains in which kinase domain is responsible for enzyme activity. CAMKIV is involved in varieties of cellular functions such as regulation of gene expression, T-cell maturation, regulation of survival phase of dendritic cells, bone growth and metabolism, memory consolidation, sperm motility, regulation of microtubule dynamics, cell-cycle progression and apoptosis. In this review, we performed an extensive analysis on structure, function and regulation of CAMKIV and associated diseases.

Structure guided design of potential inhibitors of human calcium-calmodulin dependent protein kinase IV containing pyrimidine scaffold

Calmodulin dependent protein kinase IV (CAMKIV) belongs to the serine/threonine protein kinase family and considered as an encouraging target for the development of novel anticancer agents. The interaction and binding behavior of three designed inhibitors of human CAMKIV, containing pyrimidine scaffold, was monitored by in vitro fluorescence titration and molecular docking calculations under physiological condition. In silico docking studies were performed to screen several compounds containing pyrimidine scaffold against CAMKIV. Molecular docking calculation predicted the binding of these ligands in active-site cavity of the CAMKIV structure correlating such interactions with a probable inhibition mechanism. Finally, three active pyrimidine substituted compounds (molecules 1-3) have been successfully synthesized and characterized by (1)H and (13)C NMR. Molecule 3 is showing very high binding-affinity for the CAMKIV, with a binding constant of 2.2×10(8), M(-1) (±0.20). All three compounds are nontoxic to HEK293 cells up to 50 μM. The cell proliferation inhibition study showed that the molecule 3 has lowest IC50 value (46±1.08 μM). The theoretical and experimental observations are significantly correlated. This study reveals some important observations to generate an improved pyrimidine based compound that holds promise as a therapeutic agent for the treatment of cancer and neurodegenerative diseases.

Cutting edge: Calcium/Calmodulin-dependent protein kinase type IV is essential for mesangial cell proliferation and lupus nephritis

Renal involvement in systemic lupus erythematosus remains a major cause of morbidity and mortality. Although immune parameters that instigate renal damage have been characterized, their link to local processes, which execute tissue damage, is poorly understood. Using genetic-deletion and pharmacological-inhibition approaches, we demonstrated that calcium/calmodulin-dependent protein kinase type IV, which contributes to altered cytokine production in systemic lupus erythematosus patients, controls spontaneous and platelet-derived growth factor-stimulated mesangial cell proliferation and promotes IL-6 production through AP-1. Our studies identified calcium/calmodulin-dependent protein kinase type IV as a valuable treatment target for lupus nephritis and point out the importance of local kidney factors in the expression of tissue damage that, if properly targeted, should enhance clinical benefit and limit toxicity.

Differential expression pattern of the novel serine/threonine kinase, STK33, in mice and men

Serine/threonine kinase 33 (STK33/Stk33) is a recently discovered gene whose inferred amino acid sequence translation displays characters typical for a calcium/calmodulin dependent kinase (CAMK). In this study we analysed the STK33/Stk33 RNA and protein distribution and the localization of the protein. The STK33/Stk33 expression pattern resembles those of some related members of the CAMK group. STK33/Stk33 displays a nonubiquitous and, in most tissues, low level of expression. It is highly expressed in testis, particularly in cells from the spermatogenic epithelia. Moreover, significant expression is detected in lung epithelia, alveolar macrophages, horizontal cells in the retina and in embryonic organs such as heart, brain and spinal cord. A possible role of STK33/Stk33 in spermatogenesis and organ ontogenesis is discussed.