Cross-talk between tyrosine kinase Btk and serine/threonine kinase PKCΘ in platelets: functional role of reciprocal phosphorylation

2001 ◽  
Vol 29 (3) ◽  
pp. A79-A79
Author(s):  
D. Crosby ◽  
A. W. Poole
Author(s):  
Amelia U. Schirmer ◽  
Lucy M. Driver ◽  
Megan T. Zhao ◽  
Carrow I. Wells ◽  
Julie E. Pickett ◽  
...  

1997 ◽  
Vol 45 (1) ◽  
pp. 107-118 ◽  
Author(s):  
André Nadeau ◽  
Gilles Grondin ◽  
Richard Blouin

ZPK is a recently described protein serine/threonine kinase that has been originally identified from a human teratocarcinoma cell line by the polymerase chain reaction and whose function in signal transduction has not yet been elucidated. To investigate the potential role of this protein kinase in developmental processes, we have analyzed the spatial and temporal patterns of expression of the ZPK gene in mouse embryos of different gestational ages. Northern blot analysis revealed a single mRNA species of about 3.5 KB from Day 11 of gestation onwards. In situ hybridization studies demonstrated strong expression of ZPK mRNA in brain and in a variety of embryonic organs that rely on epithelio-mesenchymal interactions for their development, including skin, intestine, pancreas, and kidney. In these tissues, the ZPK mRNA was localized primarily in areas composed of specific types of differentiating cells, and this expression appeared to be upregulated at a time concomitant with the onset of terminal differentiation. Taken together, these observations raise the possibility that the ZPK gene product is involved in the establishment and/or maintenance of a fully cytodifferentiated state in a variety of cell lineages.


Author(s):  
Novriantika Lestari

Liver fibrosis is a reversible response to a wound healing with marked accumulation of extracellular matrix which caused by injury to the liver. Liver fibrosis can be caused by various factors including alcohol and non-alcohol steatohepatitis. The process of fibrosis serves to localize the inflammation during chronic exposure. The hepatic stem cell (HSC) has a key role in the pathogenesis of liver fibrosis. The HSC activation is characterized by increased profibrogenic mediators including members of the TGF-? superfamily. In order to enable signal transduction, the mediator needs to bind to its receptors. The serine/ threonine kinase receptor is a receptor that binds to the TGF-? superfamily ligand, including TGF-?, BMP, activin and other mediators. The ligand receptor-binding activity will stimulate signal transduction that will translocate into the nucleus and phosphorylate various transcription factors that play a role in cell proliferation, differentiation, or apoptosis. There is currently no standard therapy for liver fibrosis. Based on the central role of the serine/ threonine kinase receptor in the pathogenesis of liver fibrosis, it is thought that the use of serine/ threonine kinase inhibitors is a promising therapy.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Anahita Rahmani ◽  
Danial Kheradmand ◽  
Peyman Keyhanvar ◽  
Alireza Shoae-Hassani ◽  
Amir Darbandi-Azar

Fluoxetine (FLX) is a selective serotonin reuptake inhibitor (SSRI). Its action is possibly through an increase in neural cell survival. The mechanism of improved survival rate of neurons by FLX may relate to the overexpression of some kinases such as Akt protein. Akt1 (a serine/threonine kinase) plays a key role in the modulation of cell proliferation and survival. Our study evaluated the effects of FLX on mesenchymal stem cell (MSC) fate and Akt1 phosphorylation levels in MSCs. Evaluation tests included reverse transcriptase polymerase chain reaction, western blot, and immunocytochemistry assays. Nestin, MAP-2, andβ-tubulin were detected after neurogenesis as neural markers. TenμM of FLX upregulated phosphorylation of Akt1 protein in induced hEnSC significantly. Also FLX did increase viability of these MSCs. Continuous FLX treatment after neurogenesis elevated the survival rate of differentiated neural cells probably by enhanced induction of Akt1 phosphorylation. This study addresses a novel role of FLX in neurogenesis and differentiated neural cell survival that may contribute to explaining the therapeutic action of fluoxetine in regenerative pharmacology.


Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1544 ◽  
Author(s):  
Sylwia Flis ◽  
Ewelina Bratek ◽  
Tomasz Chojnacki ◽  
Marlena Piskorek ◽  
Tomasz Skorski

Tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myeloid leukemia in the chronic phase (CML-CP). However, it is unlikely that they can completely “cure” the disease. This might be because some subpopulations of CML-CP cells such as stem and progenitor cells are resistant to chemotherapy, even to the new generation of TKIs. Therefore, it is important to look for new methods of treatment to improve therapeutic outcomes. Previously, we have shown that class I p21-activated serine/threonine kinases (PAKs) remained active in TKI-naive and TKI-treated CML-CP leukemia stem and early progenitor cells. In this study, we aimed to determine if simultaneous inhibition of BCR-ABL1 oncogenic tyrosine kinase and PAK1/2 serine/threonine kinase exert better anti-CML effect than that of individual treatments. PAK1 was inhibited by small-molecule inhibitor IPA-3 (p21-activated kinase inhibitor III), PAK2 was downregulated by specific short hairpin RNA (shRNA), and BCR-ABL1 tyrosine kinase was inhibited by imatinib (IM). The studies were conducted by using (i) primary CML-CP stem/early progenitor cells and normal hematopoietic counterparts isolated from the bone marrow of newly diagnosed patients with CML-CP and from healthy donors, respectively, (ii) CML-blast phase cell lines (K562 and KCL-22), and (iii) from BCR-ABL1-transformed 32Dcl3 cell line. Herein, we show that inhibition of the activity of PAK1 and/or PAK2 enhanced the effect of IM against CML cells without affecting the normal cells. We observed that the combined use of IM with IPA-3 increased the inhibition of growth and apoptosis of leukemia cells. To evaluate the type of interaction between the two drugs, we performed median effect analysis. According to our results, the type and strength of drug interaction depend on the concentration of the drugs tested. Generally, combination of IM with IPA-3 at the 50% of the cell kill level (EC50) generated synergistic effect. Based on our results, we hypothesize that IM, a BCR-ABL1 tyrosine kinase inhibitor, combined with a PAK1/2 inhibitor facilitates eradication of CML-CP cells.


2005 ◽  
Vol 3 (2) ◽  
pp. 198-205
Author(s):  
Margaret von Mehren

Medical management of soft tissue sarcomas (STS) has been restricted by the limited availability of active drugs. A plethora of new oncologic agents are now available, many of which have specific therapeutic targets. Gemcitabine and docetaxel is a combination of drugs that have limited single-agent activity. Yondelis, a novel chemotherapeutic that binds DNA and functions partially by inhibiting transcription, is being tested alone and in combination with doxorubicin. Inhibitors of mTOR, a serine/threonine kinase that regulates cell cycle activation and cell growth, are also being tested. Growth factor receptor inhibitors are being evaluated in a variety of sarcomas that have been found to express the targets. In addition, a variety of agents are being assessed in gastrointestinal stromal tumors (GIST). Single agents and agents combined with imatinib are being tested in imatinib-refractory and in metastatic GIST. The increased use of targeted agents underscores the need for understanding sarcoma biology.


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