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.
Casein Kinase II/metabolism* ; Phosphorylation ; Proteins

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.
Biotin ; Casein Kinase II ; metabolism ; Cell Line ; Gene Knockdown Techniques ; Humans ; Phosphorylation ; Protein Kinases ; metabolism ; Pyridines ; RNA Interference ; Transfection

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.
Casein Kinase II ; metabolism ; HEK293 Cells ; Humans ; Mitochondrial Proteins ; metabolism ; Parkinson Disease ; Protein Kinases ; metabolism ; Protein Transport ; Ubiquitin-Protein Ligases ; metabolism ; rho GTP-Binding Proteins ; metabolism

OBJECTIVEMachado-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).

METHODSThe 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.

CONCLUSIONAtaxin-3 is a substrate of protein kinase CK2.

Ataxin-3 ; Casein Kinase II ; metabolism ; Cell Line, Transformed ; Glutathione Transferase ; metabolism ; Humans ; Immunoprecipitation ; methods ; Nerve Tissue Proteins ; metabolism ; Nuclear Proteins ; metabolism ; Phosphorylation ; Repressor Proteins ; metabolism ; Transfection ; methods

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 (P<0.05, separately). The expression of HPA, CK2beta and HIF-1alpha were significantly related to the TNM stage and whether recurrence or metastasis occur after treatment (P<0.05, separate ly), but there was no obvious correlation between its expression and the sex of NPC patient (P>0.05). 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.
Carcinoma ; Casein Kinase II ; metabolism ; Female ; Heparin Lyase ; metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Male ; Middle Aged ; Nasopharyngeal Carcinoma ; Nasopharyngeal Neoplasms ; metabolism ; pathology ; Neoplasm Staging

OBJECTIVETo investigate the expression of casein kinase 2β in esophageal carcinoma tissues and analyze its clinical significance.

METHODSThe 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.

RESULTSA 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.

CONCLUSIONThe high expression of protein kinase CK2β is closely related to the carcinogenesis and malignancy of esophageal cancer.

Adult ; Aged ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Casein Kinase II ; metabolism ; Esophageal Neoplasms ; metabolism ; pathology ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Middle Aged ; Neoplasm Staging

AIMTo study the direct effect and kinetics of sodium quercetin-7,4'-disulphate (SQDS) on recombinant human protein kinase CK2 holoenzyme.

METHODSThe recombinant human CK2 holoenzyme activity was assayed by detecting incorporation of 32P of [gamma-32P] ATP into the substrate in various conditions.

RESULTSThe recombinant human CK2 was a second messenger (Ca2+, cAMP and cGMP) independent protein kinase. The characterization and function of the reconstituted holoenzyme were consistent with those of native CK2. SQDS was shown to strongly inhibit the holoenzyme activity of recombinant human protein kinase CK2 with an IC50 of 4.4 mumol.L-1, which was more effective than DRB and A3, known CK2 special inhibitors. Kinetic studies of SQDS on recombinant human CK2 showed: the inhibition was competitive with ATP and noncompetitive with casein.

CONCLUSIONSQDS is a potent inhibitor of protein kinase CK2. This study provide experimental basis for the development of more effective inhibitors of CK2 and for clinical application of SQDS in the future.

Casein Kinase II ; Dichlororibofuranosylbenzimidazole ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Humans ; Kinetics ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Quercetin ; analogs & derivatives ; pharmacology ; Recombinant Proteins ; antagonists & inhibitors ; metabolism

Deoxyhypusine is a modified lysine and formed posttranslationally to be the eukaryotic initiation factor eIF5A by deoxyhypusine synthase, employing spermidine as butylamine donor. Subsequent hydroxylation of this deoxyhypusine-containing intermediate completes the maturation of eIF5A. The previous report showed that deoxyhypusine synthase was phosphorylated by PKC in vivo and the association of deoxyhypusine synthase with PKC in CHO cells was PMA-, and Ca(2+)/phospholipid-dependent. We have extended study on the phosphorylation of deoxyhypusine synthase by protein kinase CK2 in order to define its role on the regulation of eIF5A in the cell. The results showed that deoxyhypusine synthase was phosphorylated by CK2 in vivo as well as in vitro. Endogenous CK2 in HeLa cells and the cell lysate was able to phosphorylate deoxyhypusine synthase and this modification is enhanced or decreased by the addition of CK2 effectors such as polylysine, heparin, and poly(Glu, Tyr) 4:1. Phosphoamino acid analysis of this enzyme revealed that deoxyhypusine synthase is mainly phosphorylated on threonine residue and less intensely on serine. These results suggest that phosphorylation of deoxyhypusine synthase is CK2-dependent cellular event as well as PKC-mediated effect. However, there were no observable changes in enzyme activity between the phosphorylated and unphosphorylated forms of deoxyhypusine synthase. Taken together, besides its established function in hypusine modification involving eIF5A substrate, deoxyhypusine synthase and its phosphorylation modification may have other independent cellular functions because of versatile roles of deoxyhypusine synthase.
Animals ; Casein Kinase II ; Cell Line ; Cricetinae ; Hela Cells ; Humans ; Mice ; Oxidoreductases Acting on CH-NH Group Donors/genetics/*metabolism ; Phosphoamino Acids/metabolism ; Phosphorylation ; Protein Binding ; Protein-Serine-Threonine Kinases/*metabolism ; Recombinant Proteins/genetics/metabolism

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.
Adult ; Aged ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Casein Kinase II ; biosynthesis ; Female ; Humans ; Laryngeal Mucosa ; metabolism ; pathology ; Laryngeal Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Precancerous Conditions ; metabolism ; pathology

OBJECTIVETo investigate the expression of casein kinase 2β (ck2β) in colorectal cancer in relation to the metastatic ability of the cancer cells.

METHODSThe 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.

RESULTSNegative 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.

CONCLUSIONThe high expression of ck2β in colorectal cancer is closely correlated to the carcinogenesis and metastasis of the tumor.

Adult ; Aged ; Casein Kinase II ; metabolism ; Cell Proliferation ; Cell Transformation, Neoplastic ; Colorectal Neoplasms ; metabolism ; pathology ; Female ; Humans ; Intestinal Mucosa ; metabolism ; pathology ; Male ; Middle Aged ; Tumor Cells, Cultured ; Young Adult