Advances in the structure and physiological function of protein kinase CK2 / 生物工程学报

Protein kinase CK2 is a common, evolutionarily conserved and ubiquitous protein kinase. In recent years, increasing evidences have shown that CK2 has a variety of phosphorylated protein substrates, which play important roles in growth, development and various diseases. Therefore, CK2 may participate in these physiological processes by regulating the phosphorylation of these substrates. This article briefly reviewed the structural characteristics of protein kinase CK2 and its physiological functions in growth, development, immunity, formation of tumor and other diseases, in order to provide knowledge basis for further research on the regulatory mechanism of CK2 and potential applications of its inhibitors.

Involvement of endothelial CK2 in the radiation induced perivascular resistant niche (PVRN) and the induction of radioresistance for non-small cell lung cancer (NSCLC) cells

BACKGROUND: Tumor microenvironment (TME) plays a vital role in determining the outcomes of radiotherapy. As an important component of TME, vascular endothelial cells are involved in the perivascular resistance niche (PVRN), which is formed by inflammation or cytokine production induced by ionizing radiation (IR). Protein kinase CK2 is a constitutively active serine/threonine kinase which plays a vital role in cell proliferation and inflammation. In this study, we investigated the potential role of CK2 in PVRN after IR exposure. RESULT: Specific CK2 inhibitors, Quinalizarin and CX-4945, were employed to effectively suppressed the kinase activity of CK2 in human umbilical vein endothelial cells (HUVECs) without affecting their viability. Results showing that conditioned medium from IR-exposed HUVECs increased cell viability of A549 and H460 cells, and the pretreatment of CK2 inhibitors slowed down such increment. The secretion of IL-8 and IL-6 in HUVECs was induced after exposure with IR, but significantly inhibited by the addition of CK2 inhibitors. Furthermore, IR exposure elevated the nuclear phosphorylated factor-κB (NF-κB) p65 expression in HUVECs, which was a master factor regulating cytokine production. But when pretreated with CK2 inhibitors, such elevation was significantly suppressed. CONCLUSION: This study indicated that protein kinase CK2 is involved in the key process of the IR induced perivascular resistant niche, namely cytokine production, by endothelial cells, which finally led to radioresistance of non-small cell lung cancer cells. Thus, the inhibition of CK2 may be a promising way to improve the outcomes of radiation in nonsmall cell lung cancer cells.

Casein kinase 2 is a critical determinant of the balance of Th17 and Treg cell differentiation

Th17 cells promote inflammatory reactions, whereas regulatory T (Treg) cells inhibit them. Thus, the Th17/Treg cell balance is critically important in inflammatory diseases. However, the molecular mechanisms underlying this balance are unclear. Here, we demonstrate that casein kinase 2 (CK2) is a critical determinant of the Th17/Treg cell balance. Both the inhibition of CK2 with a specific pharmacological inhibitor, CX-4945, and its small hairpin RNA (shRNA)-mediated knockdown suppressed Th17 cell differentiation but reciprocally induced Treg cell differentiation in vitro. Moreover, CX-4945 ameliorated the symptoms of experimental autoimmune encephalomyelitis and reduced Th17 cell infiltration into the central nervous system. Mechanistically, CX-4945 inhibited the IL-6/STAT3 and Akt/mTOR signaling pathways. Thus, CK2 has a crucial role in regulating the Th17/Treg balance.

Promotion of Pink1S Auto-phosphorylation with CK2β / 生物医学工程学杂志

The aim of this study is to determine the regulatory mechanism of PTEN-induced putative kinase protein 1 short isoform (PINK1S) in cytoplasm. By co-immunoprecipitation (Co-IP) assay, we identified that PINK1S interacted with the beta regulatory subunit of Casein Kinase 2 (CK2β), but not with the catalytic subunits CK2α1 and CK2α2. Furthermore, cells were transfected with PINK1S and CK2β, and then PINK1S was purified by immunoprecipitation. After detecting the phosphorylated proteins by Phos-tag Biotin, we found that CK2β overexpression increased auto-phosphorylation of PINK1S. Finally, we generated CK2β knockdown cell lines by RNA interference. Purified PINK1S from CK2β knockdown cells significantly reduced its auto-phosphorylation compared with control cells. These results suggested that CK2β functions as a regulatory subunit of PINK1S kinase complex promoted its activation by self-phosphorylation.

Expressions and correlation of HPA, CK2beta and HIF-1alpha in nasopharyngeal carcinoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the expression of HPA, CK2beta and HIF-1alpha gene in nasopharyngeal carcinoma (NPC) tissues, and the correlation between their expression with the clinical characteristics of NPC and the relativity of HPA, CK2beta and HIF-1alpha gene in NPC tissues.@*METHOD@#HPA, CK2beta and HIF-1alpha were detected with Super-Vision immunohistochemical method using antibody in 49 NPC specimens and 30 specimens with chronic nasopharyngitis tissue (CNT).@*RESULT@#The expression of HPA, CK2beta and HIF-1alpha in NPC tissue were significantly higher than those in CNT tissue (P0.05). The expression of HIF-1alpha was significantly related to the age of NPC patient (P<0.05), while HPA, CK2beta were not. The expression of HPA, CK2beta and HIF-1alpha in NPC tissue was positively correlated with each other (P<0.05, separately).@*CONCLUSION@#HPA, CK2beta and HIF-1alpha play synergetic role in development of NPC, which plays an important role in invasiveness,recurrence and metastasis of NPC. There could be a positive cooperation among HPA, CK2beta and HIF-1alpha in the carcinogenesis and development of NPC.

CK2beta promotes Pink1/Parkin-mediated MIRO1 degradation / 生物医学工程学杂志

PTEN-induced putative kinase 1 (PINK1), a Parkinson's disease (PD)-related protein, has two isoforms, the mitochondria-localized full-length isoform PINK1FL and the cytoplasm-localized short isoform PINK1-cyto. Studies have suggested that PINK1FL can selectively accumulate at the surface of damaged mitochondria and cooperate with another Parkinson's Disease-related protein PARKIN to trigger the degradation of MIRO1, a mitochondria trafficking regulator. The functions of PINK1-cyto are, however, not yet clear. To investigate the functions of PINK1-cyto, we expressed different proteins in cultured HEK293 cells by transfecting it with different plasmids, and detected the protein levels by Western blot after expressing for 24 h. We found that in cultured HEK293 cells, PINK1-cyto could also cooperate with PARKIN degrade MIRO1 in the presence of CK23, and the regulatory subunit of Casein Kinase II. Interestingly, this function of CK2P was not dependent on CK2alpha, the catalytic subunit of Casein Kinase II. We also found that CK2P could promote the direct interaction between PINK1-cyto and MIRO1 by immunocoprecipitation analysis. This result suggested that in addition to CK2alpha, CK2beta could also form a kinase complex.

Effect of casein kinase 2β in esophageal carcinoma and its clinical significance / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression of casein kinase 2β in esophageal carcinoma tissues and analyze its clinical significance.</p><p><b>METHODS</b>The expression of CK2β in a tissue chip containing 60 normal esophageal mucosa and 60 colorectal cancer specimens were detected immunohistochemically. Ten human esophageal carcinoma and adjacent normal tissues were examined for the expression of CK2β protein and mRNA using Western blotting and real-time quantitative PCR, respectively.</p><p><b>RESULTS</b>A strong expression of CK2β was found in 85.71% of the esophageal cancer tissues; 1.79% of the cancer tissues were negative for CK2β expression, and 1.79% and 10.71% of the cancer tissues were weakly and moderately positive, respectively. In the normal mucosal tissues, 96.67% of the tissues were negative for CK2β and 3.33% showed weak CK2β expression, showing a significant difference in the distribution of CK2β between normal and esophageal carcinoma tissues (P<0.001). The expression level of CK2β in esophageal cancers was associated with the pathological stage (TNM) (P=0.010). Western blotting and real-time quantitative PCR also confirmed an increased CK2β expression in the esophageal cancer tissues.</p><p><b>CONCLUSION</b>The high expression of protein kinase CK2β is closely related to the carcinogenesis and malignancy of esophageal cancer.</p>

Effects of siRNA specific to the protein kinase CK2α on apoptosis of laryngeal carcinoma cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The relationship between apoptosis and tumors is a major focus in cancer research. RNA interference (RNAi) technology has emerged as a very potent tool to generate cellular knockdown phenotypes of a desired gene. The aim of this study was to explore the effect of siRNA specific to the protein casein kinase 2α (CK2α) on apoptosis of laryngeal carcinoma cells and to explore possible mechanisms.</p><p><b>METHODS</b>An siRNA expression plasmid specific to CK2α, psiRNA-hH1neo-CK2α, and a non-specific siRNA expression plasmid, psiRNA-hH1neo-cont, were constructed and transfected into Hep-2 cells by a lipofectamine method. The mRNA and protein levels of CK2α in transfected cells were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting analysis. Apoptosis was measured by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-staining methods. The morphological changes to Hep-2 cells were observed under transmission electron microscopy (TEM). The levels of Bcl-2 and Bax proteins were measured by Western blotting analysis.</p><p><b>RESULTS</b>Levels of CK2α mRNA and protein were significantly decreased in the psiRNA-hH1neo-CK2α group compared to the other groups (P < 0.05). The apoptotic rate of the psiRNA-hH1neo-CK2α transfected group was significantly higher compared to that in the untransfected group and the siRNA-hH1neo-cont transfected group (25.66% ± 0.83%, 3.66% ± 0.43%, and 5.18% ± 0.22%) (P < 0.05). Compared with the untransfected group and the siRNA-hH1neo-cont transfected group, the psiRNA-hH1neo-CK2α transfected group presented with classical ultrastructural features of apoptosis, such as karyopyknosis, chromatic agglutination adjacent to the nuclear membrane, and apoptotic bodies. Compared with the other two groups, the level of Bcl-2 protein in the psiRNA-hH1neo-CK2α transfected group was decreased (0.20 ± 0.09 vs. 0.72 ± 0.16, 0.56 ± 0.11, P < 0.01), while the Bax protein level was increased (0.81 ± 0.17 vs. 0.26 ± 0.12, 0.33 ± 0.17, P < 0.01) and the ratio of Bcl-2 to Bax was decreased (0.25 ± 0.05 vs. 2.76 ± 0.21, 1.70 ± 0.22, P < 0.01).</p><p><b>CONCLUSIONS</b>The siRNA expression plasmid specific to CK2α could suppress CK2α expression and induce the apoptosis of laryngeal carcinoma cells. This is possibly by decreasing the Bcl-2/Bax ratio. CK2α may provide a potential therapeutic target against human laryngeal carcinoma.</p>

Role of CK2 alpha subunit in idiopathic male infertility

Protein kinase CK2 which was formerly known as casein kinase is a ubiquitously expressed protein kinase. Its expression and its activity as a protein kinase is closely connected with proliferation i.e. rapidly proliferating cells have high amounts of the enzyme and its activity in general higher than in normal cells. Protein kinase CK2 is composed of two regulatory beta subunits and two Catalytic alpha, alpha subunits, but these subunits are also found in its free form. Although CK2 is expressed in every tissue, there are some differences in the expression level in various tissues. CK2alpha is most highly expressed in brain and testes whereas only low amounts of CK2alpha are found in other tissues. The regulatory beta subunit and the catalytic alpha subunit are both absolutely necessary for the survival of cells, because the Knockouts are lethal during embryogenesis. Mice with a CK2alpha Knockout are viable however the male mice are infertile. Materials and Methods: 83 men were involved in this study, they were 17 normal men and 66 men with idiopathic infertility problems. Required sperm samples were obtained from an in vitro fertilization unit. The sperms were extracted and their protein content is determined. Equal amounts of protein will be loaded on SDS-polyacrylamide gel. After a Western Blotting, the CK2alpha, CK2alpha and CK2beta subunits were detected by specific antibodies. Results: the presence percentage of CK2alpha was 12.1% in infertile men group, and it was significantly lower compared to control group, which was 100 %. Conclusion: the absence of CK2alpha from the sperm would be used as a marker for the identification of idiopathic men infertility

Correlation of casein kinase 2β overexpression to the metastatic ability of colorectal cancer cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression of casein kinase 2β (ck2β) in colorectal cancer in relation to the metastatic ability of the cancer cells.</p><p><b>METHODS</b>The expression of ck2β in 46 normal colorectal mucosa, 20 colorectal adenomas and 66 colorectal cancers were detected immunohistochemically. In colorectal cancer cells, Ck2β protein expression was knockdown by RNA interference using ck2β-specific small interfering RNA (siRNA) and the interference efficiency was assessed by Western blotting. The effect of ck2β gene knockdown on the proliferation of the colorectal cancer cells was tested with colony formation assay, and the changes in the invasive ability of the cells were observed using Transwell chamber assay.</p><p><b>RESULTS</b>Negative or weak ck2β expression was detected in normal colorectal mucosa, with nuclear positivity in 8.7% and cytoplasmic positivity in 13.0% of the cases. Colorectal adenomas showed moderate ck2β expression, with 60% cases showing positivity in the cell nuclei and 40% in the cytoplasm. In colorectal cancers, significantly stronger expression of ck2β was found than that in colorectal adenomas and normal colorectal mucosa (P<0.05), and 75.8% cases showed positivity in the cell nuclei and 62.1% showed cytoplasmic positivity; the expression of ck2β protein in colorectal cancers with lymph node metastasis was even higher (P<0.05). Ck2β knockdown obviously inhibited the proliferation and invasiveness of colorectal cancer cells in vitro.</p><p><b>CONCLUSION</b>The high expression of ck2β in colorectal cancer is closely correlated to the carcinogenesis and metastasis of the tumor.</p>

Role of Casein Kinase 2 in Parkinsonian Toxin 1-Methyl-4-phenylpyridinium-induced Cell Death

BACKGROUND: Protein casein kinase 2 is involved in signal transduction, cell growth, and apoptosis. However, it has not been elucidated whether parkinsonian toxin 1-methyl-4-phenylpyridinium (MPP+)-induced neuronal cell death is mediated by a casein-kinase-2-mediated pathway. METHODS: We monitored apoptosis-related protein activation, changes in the level of casein kinase 2, nuclear damage, and apoptosis in differentiated PC12 cells exposed to MPP+ in combination with casein kinase 2 inhibitor. RESULTS: Casein kinase 2 inhibitors [4,5,6,7-tetrabromobenzotriazole (TBB), 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, and apigenin] reduced MPP+- and rotenone-induced cell death in differentiated PC12 cells. TBB inhibited the MPP+-induced activation of apoptosis-related proteins (decreases in Bid and Bcl-2 levels, increase in Bax levels, cytochrome c release, and caspase-3 activation), increase in casein kinase 2 levels, and nuclear damage. CONCLUSIONS: Administering casein kinase 2 inhibitor TBB at concentrations that do not induce toxic effects may reduce MPP+-induced cell death in differentiated PC12 cells by suppressing the apoptosis-related protein activation that leads to cytochrome c release and subsequent activation of caspase-3. The results suggest that MPP+-induced cell death process is mediated by a casein kinase 2 pathway.

Inhibitory effects of siRNA expression plasmid specific to protein kinase CK2alpha on human laryngeal carcinoma xenograft in nude mice / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the effect on the expression of protein kinase CK2alpha and growth of human laryngeal carcinoma xenograft in nude mice by applying small interfering RNA (siRNA) specific to protein kinase CK2alpha.@*METHOD@#Human laryngeal carcinoma Hep-2 cells were implanted under the skin of nude mice. After the tumors grew to a definite size, the tumors were injected with siRNA expression plasmid specific to protein kinase CK2alpha. The weight and volume of subcutaneous tumors were measured. The expression level of protein kinase CK2alpha mRNA and protein of tumors were measured with reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical technique, respectively.@*RESULT@#Protein kinase CK2alpha mRNA and protein expressions were significantly decreased in tumors transfected with siRNA expression plasmid specific to protein kinase CK2alpha (P<0.05). The tumor grew slowly after transfected with siRNA expression plasmid specific to protein kinase CK2alpha (P<0.01).@*CONCLUSION@#The siRNA expression plasmid specific to protein kinase CK2alpha may suppress the growth and the protein kinase CK2alpha expression of subcutaneous tumors. RNA interfering technology may be a new strategy for the treatment laryngeal cancer.

Effect of protein kinase CK2 gene silencing on radiosensitization in human nasopharyngeal carcinoma cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of protein kinase CK2 gene silencing on the radiosensitization in human nasopharyngeal carcinoma (NPC) cells and its possible mechanism.</p><p><b>METHODS</b>RNA interference (RNAi) technique was used to down-regulate the protein kinase CK2alpha expression in 5-8F cells, and clonogenic assay was employed to observe the changes in the radiosensitivity of the cells. DNA double-strand break was assessed by immunofluorescence staining of gamma-H2AX foci, and the cell apoptosis was examined using Annexin V-FITC/PI double-staining flow cytometry.</p><p><b>RESULTS</b>CK2alpha protein was successfully silenced by siRNA. CK2alpha knockdown significantly decreased the clonogenic activity and increased the radiosensitivity of the NPC cells. After a 15-min exposure of the cells to 1 Gy radiation, significant difference occurred in the gamma-H2AX foci between CK2alpha knockdown cells and the control cells (P<0.01). CK2alpha silencing significantly increased the cell apoptosis after the exposure (P<0.01).</p><p><b>CONCLUSIONS</b>Protein kinase CK2 plays an important role in the radiosensitivity of the NPC cells, and suppression of its expression might be a potential therapeutic approach of cancer.</p>

Effects of protein kinase CK2alpha on the proliferation and invasion of human nasopharyngeal carcinoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the effect of protein kinase CK2alpha expression on the proliferation and invasion of human nasopharyngeal carcinoma and related mechanism.</p><p><b>METHODS</b>RNA interference (RNAi) was used to down-regulate the protein kinase CK2alpha expression in 5-8F cells. The biological behavior of treated cells were analyzed by MTT and in-vitro invasion assays. Cell proliferation cycle was examined by flow cytometry and the phosphorylation status of Akt protein was examined by Western blotting analysis.</p><p><b>RESULTS</b>CK2alpha protein was successfully silenced by siRNA. CK2alpha knockdown significantly decreased the proliferative and invasive abilities of 5-8F cells. Flow cytometry analysis showed that the percentage of cells increased in G(0)/G(1) phase but decreased in S phase. Moreover, the expression of phosphorylated Akt was down-regulated by CK2alpha silencing.</p><p><b>CONCLUSION</b>Protein kinase CK2alpha plays an important role in the proliferation and invasion of nasopharyngeal carcinoma, and may provide a potential therapeutic target against nasopharyngeal cancer.</p>

PrP protein can bind to protein kinase CK2 both in native and recombinant forms in vitro / 病毒学报

To explore the possible molecular interaction between CK2 and PrP, the full length sequences of human CK2alpha and CK2beta genes were amplified with RT-PCR using the mRNA from cell line SH-SY5Y as the template, and then the fusion proteins HIS-CK2alpha and GST-HIS-CK2beta were expressed in E. coli. The interaction between CK2 and PrP was evaluated with immunoprecipitation and pull-down assays. The results demonstrated that recombinant PrP bound specifically with CK2alpha, but not with CK2beta. The native CK2 and PrP in the hamster brains interacted each other, forming protein complexes. The domain responsible for interacting with CK2alpha was located at the C-terminal segment of PrP (residues 90-231). This study proposed reliable experimental data for the molecular interaction between PrP and CK2alpha, both in recombinant and native categories. These results supply scientific clues for further assessing the potential biological significance of the interaction of PrP with CK2 and possible role of CK2 in the pathogenesis of prion diseases.

Casein kinase 2 interacts with and phosphorylates ataxin-3 / 神经科学通报·英文版

<p><b>OBJECTIVE</b>Machado-Joseph disease (MJD)/Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominant neurodegenerative disorder caused by an expansion of polyglutamine tract near the C-terminus of the MJD1 gene product, ataxin-3. The precise mechanism of the MJD/SCA3 pathogenesis remains unclear. A growing body of evidence demonstrates that phosphorylation plays an important role in the pathogenesis of many neurodegenerative diseases. However, few kinases are known to phosphorylate ataxin-3. The present study is to explore whether ataxin-3 is a substrate of casein kinase 2 (CK2).</p><p><b>METHODS</b>The interaction between ataxin-3 and CK2 was identified by glutathione S-transferase (GST) pull-down assay and co-immunoprecipition assay. The phosphorylation of ataxin-3 by CK2 was measured by in vitro phosphorylation assays. Results (1) Both wild type and expanded ataxin-3 interacted with CK2alpha and CK2beta in vitro. (2) In 293 cells, both wild type and expanded ataxin-3 interacted with CK2beta, but not CK2alpha. (3) CK2 phosphorylated wild type and expanded ataxin-3.</p><p><b>CONCLUSION</b>Ataxin-3 is a substrate of protein kinase CK2.</p>

The expressions and significance of CK2 in normal laryngeal mucosa, laryngeal precancerosis and laryngeal squamous cell carcinoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the expression of protein kinase CK2 and its relationship with the development, progress, invasion and metastasis of squamous cell carcinoma of larynx (LSCC).@*METHOD@#Immunohistochemical SP staining method was used to assess the expression of CK2 in 18 cases of normal laryngeal mucosa, 14 cases of polyp of vocal cord, 11 cases of larynx papilloma and 50 cases of LSCC patients. And RT-PCR was used to detect the expression of CK2alpha mRNA and CK2beta mRNA in 50 cases of LSCG patients. The relationship between CK2alpha and CK2p was evaluated.@*RESULT@#The positive expression rate of CK2alpha and CK2beta in normal laryngeal mucosa, polyp of vocal cord and tissues close to carcinoma by 1.0 cm, nonmetastatic lymph nodes were lower than that in tissues close to carcinoma by 0.5 cm and laryngeal papilloma. The positive expression rate of CK2alpha and CK2beta in laryngeal carcinoma and metastatic lymph nodes were the highest among the groups. The expression rate of CK2alpha and CK2beta in tissues of laryngeal carcinoma and metastatic lymph nodes of neck was significantly higher than that of laryngeal papilloma and tissues close to carcinoma by 0.5 cm (P < 0.05). In the group of LSCC, the expression of CK2alpha in G2 and in G3 was significantly higher than that in G1 (P < 0.05). While the age of the patients, TNM stage and lymphatic metastasis didn't change in the expression of CK2alpha obviously. The expression of CK2beta correlates to the differentiation grading and lymphatic metastasis in LSCC patients, but not to the age and TNM stage. The result from RT-PCR was highly consistent with that from immunohistochemical SP staining. There was a positive correlation between the expression of CK2alpha in LSCC patients and that of CK2beta.@*CONCLUSION@#The over expression of protein kinase CK2 may be an accelerator to the formation and development of LSCC. Protein kinase CK2 may be one of the predictors for the malignant grade of LSCC. To inhibit the over expression might be new therapeutic methods for LSCC.

Inhibitory effects of small interfering RNA specific to protein kinase CK2a on the growth of laryngeal carcinoma cells / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To assess the effect of small interfering RNA (siRNA) specific to protein kinase CK2a on proliferation and apoptosis of Hep-2 cell line.</p><p><b>METHODS</b>siRNA expression plasmid psiRNA-hH1neo-CK2 specific to protein kinase CK2a and non-specific siRNA expression plasmid psiRNA-hH1neo-cont were constructed respectively, and then were transfected into Hep-2 cells by lipofectamine methods. Protein kinase CK2a mRNA and protein of the transfected cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western Blot, respectively. Proliferation and apoptosis of the transfected cells were observed by methyl thiazolyl tetrazolium (MTT) method and flow cytometry (FCM), respectively.</p><p><b>RESULTS</b>Protein kinase CK2a mRNA and protein expressions were significantly decreased in the cells transfected with psiRNA-hH1neo-CK2 (P < 0.05). The Hep-2 cells grew slowly after transfected with psiRNA-hH1neo-CK2(P < 0.05). Obvious subdiploid peaks were found in the cells transfected with psiRNA-hH1neo-CK2 (P < 0.05).</p><p><b>CONCLUSIONS</b>siRNA expression plasmid specific to protein kinase CK2a suppressed the protein kinase CK2a expression and the proliferation of Hep-2, and induced apoptosis of Hep-2 cells.</p>

Phospholipase D is activated and phosphorylated by casein kinase-II in human U87 astroglioma cells

Elevated expression of protein casein kinase II (CKII) stimulated basal phospholipase D (PLD) activity as well as PMA-induced PLD activation in human U87 astroglioma cells. Moreover, CKII-selective inhibitor, emodin and apigenin suppressed PMA-induced PLD activation in a dose-dependent manner as well as basal PLD activity, suggesting the involvement of CKII in the activation of both PLD1 and PLD2. CKII was associated with PLD1 and PLD2 in co-transfection experiments. Furthermore, CKII induced serine/threonine phosphorylation of PLD2 in vivo, and the multiple regions of PLD2 were phosphorylated by CKII in vitro kinase assay using glutathione S-transferase-PLD2 fusion protein fragments. Elevated expression of CKII or PLD increased cell proliferation but pretreatment of cells with 1-butanol suppressed CKII-induced cell proliferation. These results suggest that CKII is involved in proliferation of U87 cells at least in part, through stimulation of PLD activity.

Cloning and expression in Escherichia coli of a new gene of Schistosoma japonicum encoding casein kinase II beta subunit / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Nowadays it is now a focus topic in schistosomiasis research to find ideal vaccine candidates and new drug targets for developing anti-schistosomiasis vaccine. We cloned a new gene, casein kinase II beta subunit, of Schistosoma japonicum (S. japonicum) and express it in Escherichia coli (E. coli).</p><p><b>METHODS</b>The ESTs obtained in our laboratory were analyzed by homologous searching, and a new gene was recognized. The full-length cDNA of the new gene was obtained by joining the 3'RACE PCR fragment and the EST clone. To express the new gene, the cDNA was cloned into pGEX-4T-1 vector and then transformed into E. coli JM109. The recombinant protein was analyzed by SDS-PAGE and Western-blot.</p><p><b>RESULTS</b>A 908 bp cDNA was isolated from S. japonicum and identified to be casein kinase II beta subunit gene by sequence analysis. The open reading frame of the gene encodes a protein of 217 amino acids exhibiting 75.8%, 75.8%, 73.9%, 68.2%, 51.6% identity to the amino acids sequence of the corresponding genes of Homo sapiens (H. sapiens), Xenopus laevi (X. laevi), Drosophila melanogaster (D. melanogaster), Caenorhabditis elegan (C. elegan), and Schizosaccharomyces pombe (S. promber) respectively. The predicted molecular weight of the protein was 24.921 kDa. The new cDNA sequence had been submitted to GenBank, and its accession number is AY241391. This cDNA was subcloned into the pGEX-4T-1 vector and expressed in E. coli JM109. The recombinant protein could be recognized by the S. japonicum infected rabbit serum.</p><p><b>CONCLUSION</b>The full-length cDNA sequences encoding S. japonicum casein kinase II beta subunit were firstly sequenced, cloned, and expressed in E. coli.</p>