Regulation of the cytokinesis cleavage furrow by PKCε

2014 ◽  
Vol 42 (6) ◽  
pp. 1534-1537 ◽  
Author(s):  
Nicola Brownlow ◽  
Tanya Pike ◽  
Victoria Crossland ◽  
Jeroen Claus ◽  
Peter Parker
Keyword(s):  
Cell Cycle ◽  
Actin Binding ◽  
Cleavage Furrow ◽  
Binding Region ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Dna Segregation ◽  
Daughter Cells ◽  
Cell Adhesion And Migration ◽  
And Migration

Cytokinesis is the final act of the cell cycle where the replicated DNA and cellular contents are finally split into two daughter cells. This process is very tightly controlled as DNA segregation errors and cytokinesis failure is commonly associated with aneuploidy and aggressive tumours. Protein kinase Cε (PKCε) is a lipid-activated serine/threonine kinase that is part of the PKC superfamily. PKCε plays a complex role in the regulation of migration, adhesion and cytokinesis and in the present article we discuss the interplay between these processes. Integrin-mediated interaction with the actin cytoskeleton is a known regulator of cell adhesion and migration and there is emerging evidence that this pathway may also be essential for cytokinesis. We discuss evidence that a known actin-binding region in PKCε is involved in PKCε-mediated regulation of cytokinesis, providing a link between integrin-mediated stabilization of the cytokinesis furrow and PKCε recruitment.

scholarly journals Silencing MASTL Inhibits Cell Proliferation and Migration of Gastric Cancer MGC-803 Cells Via Suprressing AKT, mTOR, p38 Signal Pathways

2020 ◽  
Author(s):  
caixia An ◽  
hailong li ◽  
Rong Niu ◽  
xiaoguang liu ◽  
Yonghua Hu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Signal Pathways ◽  
Cyclin Dependent Kinase ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Mrna Microarray ◽  
And Migration

Abstract Background: Microtubule-associated serine/threonine kinase (MASTL) functions to regulate chromosome condensation and mitotic progression. Emerging reports showed that aberrant MASTL expression is commonly implicated in various human cancers and act as an oncogene. This study aimed to discover the potential significance of MASTL in gastric cancer, and to uncover relevant mechanisms. Methods: Lentivirus MASTL-shRNA was constructed and infected into MGC-803 cells to analysis its influences on cell proliferation by Green fluorescent protein (GFP)-based cellomics and colony formation assay, cell invasion and migration by transwell assay, apoptosis and cell cycle by flow cytometry detection, respectively. Nude mice and fluorescence imaging were used to characterize the regulation of tumor growth in vivo. Affymetrix mRNA microarray assay combined KEGG enrichment analysis were used to screen relevant molecules related to MASTL silencing. Finally，several aberrantly expressed genes were validated by quantitative reverse transcription PCR(RT-qPCR)and western blot detection. Results: Silencing MASTL significantly inhibited cell proliferation, migration and invasion, arrested cell cycle at G1 stage. Silencing MASTL reduced tumor growth in nude mice, and fluorescence imaging indicated that the total radiant efficiency of mice in the Lv-shMAST group was markedly reduced compared with in mice in the Lv-shCtrl group in vivo. Affymetrix mRNA microarray assay revealed that 124 genes upregulated, 167 genes downregulated. RT-qPCR and western blotting validation showed that cyclin dependent kinase 6(CDK6), bone morphogenetic protein 2(BMP2), snail family transcriptional repressor 2(SNAI2), phosphorylation-mechanistic target of rapamycin kinase (p-mTOR), phosphorylation-AKT serine/threonine kinase (p-AKT) and phosphorylation-p38 kinase (p-p38) are downregulated, and cyclin dependent kinase inhibitor 1A (CDKN1A) is upregulated. Conclusions: Silencing MASTL could significantly inhibit cell growth, migration ability, induce apoptosis, arrest cell cycle at G1 stage, and the mechanisms of which were mediated via inactivation of mTOR, AKT, p38 signal pathways.

scholarly journals Membrane localization of the kinase which phosphorylates p34cdc2 on threonine 14.

1994 ◽  
Vol 5 (3) ◽  
pp. 273-282 ◽  
Author(s):  
S Kornbluth ◽  
B Sebastian ◽  
T Hunter ◽  
J Newport
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Protein Kinases ◽  
Membrane Fraction ◽  
Kinase Activity ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Dual Specificity ◽  
Detergent Extraction

The key regulator of entry into mitosis is the serine/threonine kinase p34cdc2. This kinase is regulated both by association with cyclins and by phosphorylation at several sites. Phosphorylation at Tyr 15 and Thr 14 are believed to inhibit the kinase activity of cdc2. In Schizosaccharomyces pombe, the wee1 (and possibly mik1) protein kinase catalyzes phosphorylation of Tyr 15. It is not clear whether these or other, as yet unidentified, protein kinases phosphorylate Thr 14. In this report we show, using extracts of Xenopus eggs, that the Thr 14-directed kinase is tightly membrane associated. Specifically, we have shown that a purified membrane fraction, in the absence of cytoplasm, can promote phosphorylation of cdc2 on both Thr 14 and Tyr 15. In contrast, the cytoplasm can phosphorylate cdc2 only on Tyr 15, suggesting the existence of at least two distinctly localized subpopulations of cdc2 Tyr 15-directed kinases. The membrane-associated Tyr 15 and Thr 14 kinase activities behaved similarly during salt or detergent extraction and were similarly regulated during the cell cycle and by the checkpoint machinery that delays mitosis while DNA is being replicated. This suggests the possibility that a dual-specificity membrane-associated protein kinase may catalyze phosphorylation of both Tyr 15 and Thr 14.

scholarly journals SIRT7 Deacetylates STRAP to Regulate p53 Activity and Stability

2020 ◽  
Vol 21 (11) ◽  
pp. 4122 ◽  
Author(s):  
Miao Yu ◽  
Xiaoyan Shi ◽  
Mengmeng Ren ◽  
Lu Liu ◽  
Hao Qi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Death ◽  
Cell Cycle Arrest ◽  
Creb Binding Protein ◽  
Serine Threonine Kinase ◽  
Receptor Associated Protein ◽  
Threonine Kinase ◽  
P53 Signaling ◽  
Cycle Arrest

Serine-threonine kinase receptor-associated protein (STRAP) functions as a regulator of both TGF-β and p53 signaling that participates in the regulation of cell proliferation and cell death in response to various stresses. Here, we demonstrate that STRAP acetylation plays an important role in p53-mediated cell cycle arrest and apoptosis. STRAP is acetylated at lysines 147, 148, and 156 by the acetyltransferases CREB-binding protein (CBP) and that the acetylation is reversed by the deacetylase sirtuin7 (SIRT7). Hypo- or hyperacetylation mutations of STRAP at lysines 147, 148, and 156 (3KR or 3KQ) influence its activation and stabilization of p53. Moreover, following 5-fluorouracil (5-FU) treatment, STRAP is mobilized from the cytoplasm to the nucleus and promotes STRAP acetylation. Our finding on the regulation of STRAP links p53 with SIRT7 influencing p53 activity and stability.

scholarly journals Tyr198 is the Essential Autophosphorylation Site for STK16 Localization and Kinase Activity

2019 ◽  
Vol 20 (19) ◽  
pp. 4852 ◽  
Author(s):  
Junjun Wang ◽  
Juanjuan Liu ◽  
Xinmiao Ji ◽  
Xin Zhang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Kinase Domain ◽  
Serine Threonine Kinase ◽  
Cycle Progression ◽  
Threonine Kinase ◽  
Cellular Processes ◽  
Activation Segment ◽  
And Function

STK16, reported as a Golgi localized serine/threonine kinase, has been shown to participate in multiple cellular processes, including the TGF-β signaling pathway, TGN protein secretion and sorting, as well as cell cycle and Golgi assembly regulation. However, the mechanisms of the regulation of its kinase activity remain underexplored. It was known that STK16 is autophosphorylated at Thr185, Ser197, and Tyr198 of the activation segment in its kinase domain. We found that STK16 localizes to the cell membrane and the Golgi throughout the cell cycle, but mutations in the auto-phosphorylation sites not only alter its subcellular localization but also affect its kinase activity. In particular, the Tyr198 mutation alone significantly reduced the kinase activity of STK16, abolished its Golgi and membrane localization, and affected the cell cycle progression. This study demonstrates that a single site autophosphorylation of STK16 could affect its localization and function, which provides insights into the molecular regulatory mechanism of STK16’s kinase activity.

Inhibition of the Serine/Threonine Kinase Pim-1 Has Anti-Proliferative Effects In Acute Myeloid Leukemia (AML) and Sensitizes Multidrug Resistant Cells to Chemotherapy

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1832-1832
Author(s):  
Karthika Natarajan ◽  
Mehmet Burcu ◽  
Maria R. Baer
Keyword(s):  
Cell Cycle ◽  
Drug Resistance ◽  
Cell Survival ◽  
Cell Lines ◽  
Colony Formation ◽  
Multidrug Resistant ◽  
Serine Threonine Kinase ◽  
Hl60 Cells ◽  
Threonine Kinase ◽  
Resistance Protein

Abstract Abstract 1832 Poster Board I-812 The serine/threonine kinase Pim-1, encoded by a proto-oncogene originally identified as the proviral integration site in Moloney murine leukemia virus lymphomagenesis, phosphorylates and thereby increases expression of multiple cellular proteins, including the pro-apoptotic protein BAD, the cell cycle regulatory proteins p21, p27, Cdc25A and Cdc25C, the transcription factors SOCS-1, RUNX3 and c-myc and, as we recently demonstrated, the drug resistance-associated ATP-binding cassette (ABC) proteins P-glycoprotein (Pgp, ABCB1) and breast cancer resistance protein (BCRP, ABCG2). Pim-1 is synthesized in an active form by virtue of its hinge structure, and its activity is therefore regulated solely by its level of expression. Pim-1 is overexpressed downstream of FLT3 in AML cells with FLT3-ITD, but less is known about its expression and role in AML with wild-type (wt) FLT3. We studied Pim-1 expression and the effects of Pim-1 inhibition on AML cell survival, proliferation, apoptosis and chemosensitivity. Cell lines studied included HL60, K562, U937, Kasumi-1 and EOL-1 FLT3-wt cells and MV4-11 and MOLM-14 FLT3-ITD cells, as well as Pgp+ HL60/VCR and BCRP+ 8226/MR20 and parental 8226 myeloma cells as a model for BCRP-mediated drug resistance. Expression of Pim-1 and of phospho-BAD at S112, a measure of Pim-1 activity, was studied by Western blot analysis, normalized to GAPDH expression. Effects of the Pim-1 inhibitor SGI-1776 (SuperGen, Inc., Dublin, CA) on survival, cell cycle, apoptosis and colony growth were measured in WST-1 cell survival, flow cytometric cell cycle and apoptosis, and methylcellulose colony formation assays, respectively. SGI-1776 inhibits Pim-1 at a concentration of 7 +/− 1.8 nM, but is more than 90% bound to human plasma protein, so that its Pim-1 inhibitory concentration in cell culture-based assays is in μM range. Of note, SGI-1776 also inhibits FLT3 in this concentration range. Pim-1 was expressed in all cell lines studied, and expression of Pim-1 and of phopho-BAD did not differ between FLT3-ITD and FLT3-wt cells, nor between drug-resistant and parental cells. SGI-1776 decreased viable cell numbers in 96-hour WST-1 cell viability assays, with IC50's of 5 to 7 μM in FLT-wt cells, while IC50's were 20 and 65 nM, respectively, in MV4-11 and MOLM-14 FLT3-ITD cells. SGI-1776 IC50's did not differ between Pgp+ or BCRP+ cells and parental cells. In FLT3-wt cells, SGI-1776 had no effect on cell cycle at concentrations up to 5 μM, and caused apoptosis at 10 μM, while in FLT3-ITD cells, G1 arrest and apoptosis occurred at 100 nM. HL60 colony formation was completely inhibited by 5 μM SGI-1776, while MOLM-14 colony formation inhibition occurred at 500 nM. Finally, SGI-1776 sensitized multidrug resistant, but not parental, cells to multidrug resistance protein substrate, but not non-substrate, drugs. SGI-1776 at 1 μM decreased the IC50 of the Pgp substrate chemotherapy drug daunorubicin in Pgp+ HL60/VCR cells 7-fold, but had no effect on daunorubicin IC50 in HL60 cells, nor on IC50 of the non-Pgp substrate cytarabine in either cell line. SGI-1776 at 1 μM also decreased the IC50 of the BCRP substrate chemotherapy drug mitoxantrone in BCRP+ 8226/MR20 cells 7-fold. SGI-1776 at 1 μM doubled the percentage of apoptotic cells among HL60/VCR, but not HL60, cells exposed to daunorubicin and 8226/MR20 cells exposed to mitoxantrone. Finally, SGI-1776 at 1 μM decreased HL60/VCR colony formation in the presence of daunorubicin, but not cytarabine, but had no effect in HL60 cells, and also decreased 8226/MR20 colony formation in the presence of mitoxantrone, but not cytarabine. Thus the Pim-1 inhibitor SGI-1776 has anti-proliferative effects in AML cells with wt FLT3 as well FLT3-ITD, and sensitizes Pgp+ and BCRP+ multidrug resistant cells to chemotherapy. These data support clinical trials of SGI-1776 in AML with wt FLT3 as well FLT3-ITD, as a single agent and in combination with chemotherapy in multidrug resistant AML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Par1b links lumen polarity with LGN–NuMA positioning for distinct epithelial cell division phenotypes

2013 ◽  
Vol 203 (2) ◽  
pp. 251-264 ◽  
Author(s):  
Francisco Lázaro-Diéguez ◽  
David Cohen ◽  
Dawn Fernandez ◽  
Louis Hodgson ◽  
Sven C.D. van IJzendoorn ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Mdck Cells ◽  
Rho Kinase ◽  
Cell Contact ◽  
Cleavage Furrow ◽  
Mitotic Spindles ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Rhoa Activity ◽  
Columnar Organization

Columnar epithelia establish their luminal domains and their mitotic spindles parallel to the basal surface and undergo symmetric cell divisions in which the cleavage furrow bisects the apical domain. Hepatocyte lumina interrupt the lateral domain of neighboring cells perpendicular to two basal domains and their cleavage furrow rarely bifurcates the luminal domains. We determine that the serine/threonine kinase Par1b defines lumen position in concert with the position of the astral microtubule anchoring complex LGN–NuMA to yield the distinct epithelial division phenotypes. Par1b signaling via the extracellular matrix (ECM) in polarizing cells determined RhoA/Rho-kinase activity at cell–cell contact sites. Columnar MDCK and Par1b-depleted hepatocytic HepG2 cells featured high RhoA activity that correlated with robust LGN–NuMA recruitment to the metaphase cortex, spindle alignment with the substratum, and columnar organization. Reduced RhoA activity at the metaphase cortex in HepG2 cells and Par1b-overexpressing MDCK cells correlated with a single or no LGN–NuMA crescent, tilted spindles, and the development of lateral lumen polarity.

scholarly journals LIN28B-PDZ Binding Kinase Signaling Promotes Neuroblastoma Metastasis

2019 ◽  
Author(s):  
Dongdong Chen ◽  
Julie Cox ◽  
Jayabhargav Annam ◽  
Melanie Weingart ◽  
Grace Essien ◽  
...  
Keyword(s):  
Rna Binding ◽  
Xenograft Model ◽  
Aurora Kinase ◽  
Serine Threonine Kinase ◽  
Self Renewal ◽  
Threonine Kinase ◽  
Murine Xenograft Model ◽  
Oncogenic Driver ◽  
And Migration ◽  
Cure Rates

ABSTRACTNeuroblastoma is an aggressive pediatric malignancy of the neural crest with suboptimal cure rates and a striking predilection for widespread metastases, underscoring the need to identify novel therapeutic vulnerabilities. We recently identified the RNA binding protein LIN28B as a driver in high-risk neuroblastoma and demonstrated it promotes oncogenic cell proliferation by coordinating a RAN-Aurora kinase A network. Here, we demonstrate that LIN28B influences another key hallmark of cancer, metastatic dissemination. Using a murine xenograft model of neuroblastoma dissemination, we show that LIN28B promotes metastasis. We demonstrate that this is in part due to the effects of LIN28B on self-renewal and migration, providing an understanding of how LIN28B shapes the metastatic phenotype. Our studies reveal that the let-7 family, which LIN28B inhibits, opposes the effects of LIN28B. Next, we identify PDZ Binding Kinase (PBK) as a novel LIN28B target. PBK is a serine/threonine kinase that promotes the proliferation and self-renewal of neural stem cells and serves as an oncogenic driver in multiple aggressive malignancies. We demonstrate that PBK is both a novel direct target of let-7 and that MYCN regulates PBK expression, thus elucidating two oncogenic drivers that converge on PBK. Functionally, PBK promotes self-renewal and migration, phenocopying LIN28B. Taken together, our findings define a role for LIN28B in neuroblastoma metastasis and define the targetable kinase PBK as a potential novel vulnerability in metastatic neuroblastoma.

scholarly journals The Cell Cycle Checkpoint System MAST(L)-ENSA/ARPP19-PP2A is Targeted by cAMP/PKA and cGMP/PKG in Anucleate Human Platelets

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 472 ◽  
Author(s):  
Elena J. Kumm ◽  
Oliver Pagel ◽  
Stepan Gambaryan ◽  
Ulrich Walter ◽  
René P. Zahedi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Map Kinases ◽  
Human Platelets ◽  
Cell Cycle Checkpoint ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Proteomic Data ◽  
Cycle Checkpoint ◽  
Phosphatase 2A

The cell cycle is controlled by microtubule-associated serine/threonine kinase-like (MASTL), which phosphorylates the cAMP-regulated phosphoproteins 19 (ARPP19) at S62 and 19e/α-endosulfine (ENSA) at S67and converts them into protein phosphatase 2A (PP2A) inhibitors. Based on initial proteomic data, we hypothesized that the MASTL-ENSA/ARPP19-PP2A pathway, unknown until now in platelets, is regulated and functional in these anucleate cells. We detected ENSA, ARPP19 and various PP2A subunits (including seven different PP2A B-subunits) in proteomic studies of human platelets. ENSA-S109/ARPP19–S104 were efficiently phosphorylated in platelets treated with cAMP- (iloprost) and cGMP-elevating (NO donors/riociguat) agents. ENSA-S67/ARPP19-S62 phosphorylations increased following PP2A inhibition by okadaic acid (OA) in intact and lysed platelets indicating the presence of MASTL or a related protein kinase in human platelets. These data were validated with recombinant ENSA/ARPP19 and phospho-mutants using recombinant MASTL, protein kinase A and G. Both ARPP19 phosphorylation sites S62/S104 were dephosphorylated by platelet PP2A, but only S62-phosphorylated ARPP19 acted as PP2A inhibitor. Low-dose OA treatment of platelets caused PP2A inhibition, diminished thrombin-stimulated platelet aggregation and increased phosphorylation of distinct sites of VASP, Akt, p38 and ERK1/2 MAP kinases. In summary, our data establish the entire MASTL(like)–ENSA/ARPP19–PP2A pathway in human platelets and important interactions with the PKA, MAPK and PI3K/Akt systems.

The C. elegans par-4 gene encodes a putative serine-threonine kinase required for establishing embryonic asymmetry

Development ◽  
2000 ◽  
Vol 127 (7) ◽  
pp. 1467-1475 ◽  
Author(s):  
J.L. Watts ◽  
D.G. Morton ◽  
J. Bestman ◽  
K.J. Kemphues
Keyword(s):  
Cell Cycle ◽  
Kinase Domain ◽  
Missense Mutations ◽  
Serine Threonine Kinase ◽  
Cell Stage ◽  
Threonine Kinase ◽  
C Elegans ◽  
Human Kinase ◽  
Early Embryos ◽  
Peutz Jeghers Syndrome

During the first cell cycle of Caenorhabditis elegans embryogenesis, asymmetries are established that are essential for determining the subsequent developmental fates of the daughter cells. The maternally expressed par genes are required for establishing this polarity. The products of several of the par genes have been found to be themselves asymmetrically distributed in the first cell cycle. We have identified the par-4 gene of C. elegans, and find that it encodes a putative serine-threonine kinase with similarity to a human kinase associated with Peutz-Jeghers Syndrome, LKB1 (STK11), and a Xenopus egg and embryo kinase, XEEK1. Several strong par-4 mutant alleles are missense mutations that alter conserved residues within the kinase domain, suggesting that kinase activity is essential for PAR-4 function. We find that the PAR-4 protein is present in the gonads, oocytes and early embryos of C. elegans, and is both cytoplasmically and cortically distributed. The cortical distribution begins at the late 1-cell stage, is more pronounced at the 2- and 4-cell stages and is reduced at late stages of embryonic development. We find no asymmetry in the distribution of PAR-4 protein in C. elegans embryos. The distribution of PAR-4 protein in early embryos is unaffected by mutations in the other par genes.

Multiple Myeloma Cells Survival and Proliferation Rely on High Levels and Activity of the Serine-Threonine Kinase CK2.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 643-643 ◽  
Author(s):  
Francesco A. Piazza ◽  
Maria Ruzzene ◽  
Giovanni Di Maira ◽  
Enrico Brunetta ◽  
Luca Bonanni ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Transcriptional Activity ◽  
Kinase Activity ◽  
Serine Threonine Kinase ◽  
Cycle Progression ◽  
Threonine Kinase ◽  
Protein Levels ◽  
Tnf Α ◽  
Ck2 Inhibitors

Abstract Survival and proliferation of Multiple Myeloma plasma cells (MMPCs) depend on the activation of signaling pathways through the interaction with the surrounding bone marrow microenvironment. CK2 is a ubiquitous cellular serine-threonine kinase, whose involvement in oncogenic transformation, apoptosis and cell cycle progression has recently become matter of intense research. Due to its connection with signaling molecules pivotal for plasma cell (PCs) survival, such as those implicated in the TNF-α/NF-κB, IGF1/PI3K/AKT and Wnt/β-catenin pathways, CK2 is likely to play a central role in MM biology. We investigated CK2 function in MMPCs survival and cell cycle progression, in the modulation of the sensitivity to chemotherapeutics and in the regulation of the I-κB/NF-κB dependent pathway. We first analysed the CK2 protein levels and specific kinase activity in MMPCs. Different cell lines and highly purified CD138+ PCs from 5 patients were used. We observed higher protein levels of the CK2 catalytic subunit αin the neoplastic MMPCs than in controls (resting peripheral blood and splenic B lymphocytes). Moreover, also the total CK2-dependent kinase activity was found significantly increased in MMPCs. We also assessed the levels and pattern of total protein phosphorylation by radioactive phosphate incorporation assay. We found that MMPCs share a similar pattern of phoshorylated proteins. The degree of phosphorylation of some of these proteins was significantly reduced in the presence of specific CK2 inhibitors. Next, using a panel of highly specific CK2 inhibitors, we studied the effects of hampering CK2 function in MMPCs. A dose-dependent cytotoxic effect was observed after the treatment with such compounds that was associated with the activation of both the extrinsic and intrinsic caspase-dependent pathways, the release from mitochondria of cytochrome c and smac/diablo and cell cycle arrest in G2-M. A possible role for CK2 inhibition in sensitising MMPCs to melphalan-induced apoptosis was also investigated. Indeed, CK2 blockade lowered the threshold of sensitivity of MMPCs to the cytotoxic effect of melphalan. We then looked at the consequences of CK2 blockade on the NF-κB dependent signaling cascade. Basal and TNF-α-dependent I-κB-αdegradation, as well as NF-κB transcriptional activity upon TNF-αstimulation, were partially impaired by CK2 blockade in MMPCs. Finally, we detected association between the endogenous αcatalytic subunit of CK2 and the NF-κB p50/p105 member by confocal microscopy and co-immunoprecipitation. Altogether, our data suggest a pivotal role for CK2 in controlling survival, proliferation and sensitivity to chemotherapeutics of MMPCs and implicate this kinase in the regulation of the NF-κB pathway in MM through the modulation of I-κB protein levels and NF-κB transcriptional activity. This latter effect is possibly exerted through physical association of CK2 with NF-κB transcription factors. Our findings also suggest that CK2 inhibition could be exploited as a novel therapeutic approach for MM.

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