scholarly journals Quantitative Phosphoproteomic Analyses Identify STK11IP as a Lysosome-Specific Substrate of mTORC1 that Regulates Lysosomal Acidification

2021 ◽  
Author(s):  
Zhenzhen Zi ◽  
Zhuzhen Zhang ◽  
Qiang Feng ◽  
Chiho Kim ◽  
Philipp E. Scherer ◽  
...  
Keyword(s):  
Specific Substrate ◽  
Serine Threonine Kinase ◽  
Deficient Diet ◽  
Threonine Kinase ◽  
Promising Therapeutic Target ◽  
Evolutionarily Conserved ◽  
Cell Growth And Proliferation ◽  
Lysosomal Acidification ◽  
Lysosomal Proteins

The evolutionarily conserved serine/threonine kinase mTORC1 is a central regulator of cell growth and proliferation. mTORC1 is activated on the lysosome surface. However, once mTORC1 is activated, it is unclear whether mTORC1 phosphorylates local lysosomal proteins to regulate specific aspects of lysosomal biology. Through cross-reference analyses of lysosome proteomic with mTORC1-regulated phosphoproteomic, we identified STK11IP as a novel lysosome-specific substrate of mTORC1. mTORC1 directly phosphorylates STK11IP at S404. Knockout of STK11IP led to a robust increase of autophagosome-lysosome fusion and autophagy flux. Dephosphorylation of STK11IP at S404 represses the role of STK11IP as an autophagy inhibitor. Mechanistically, STK11IP binds to V-ATPase, and regulates the activity of V-ATPase. Knockout of STK11IP protects mice from fasting and Methionine-Choline-Deficient Diet (MCD) diet induced fatty liver. Thus, our study demonstrates that STK11IP phosphorylation represents a novel mechanism for mTORC1 to regulate lysosomal acidification, and points to STK11IP as a promising therapeutic target for the amelioration of diseases with aberrant autophagy signaling.

scholarly journals Non-canonical role of Hippo tumor suppressor serine/threonine kinase 3 STK3 in prostate cancer.

2021 ◽  
Author(s):  
Amelia U. Schirmer ◽  
Lucy M. Driver ◽  
Megan T. Zhao ◽  
Carrow I. Wells ◽  
Julie E. Pickett ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Tumor Suppressor ◽  
Serine Threonine Kinase ◽  
Threonine Kinase

scholarly journals In Situ Hybridization Analysis of ZPK Gene Expression During Murine Embryogenesis

1997 ◽  
Vol 45 (1) ◽  
pp. 107-118 ◽  
Author(s):  
André Nadeau ◽  
Gilles Grondin ◽  
Richard Blouin
Keyword(s):  
In Situ Hybridization ◽  
Northern Blot Analysis ◽  
Spatial And Temporal Patterns ◽  
Serine Threonine Kinase ◽  
Teratocarcinoma Cell ◽  
Threonine Kinase ◽  
Cell Lineages ◽  
Polymerase Chain

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.

scholarly journals ROLE OF SERIN/ THREONINE KINASE INHIBITOR IN THERAPY NON-ALCOHOLIC STEATOHEPATITIS AND ALCOHOLIC HEPATITIS

2019 ◽  
Vol 6 (3) ◽  
pp. 101-109
Author(s):  
Novriantika Lestari
Keyword(s):  
Signal Transduction ◽  
Liver Fibrosis ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Binding Activity ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Receptor Binding Activity ◽  
Marked Accumulation

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.

scholarly journals Neurogenesis and Increase in Differentiated Neural Cell Survival via Phosphorylation of Akt1 after Fluoxetine Treatment of Stem Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Anahita Rahmani ◽  
Danial Kheradmand ◽  
Peyman Keyhanvar ◽  
Alireza Shoae-Hassani ◽  
Amir Darbandi-Azar
Keyword(s):  
Survival Rate ◽  
Cell Survival ◽  
Neural Cell ◽  
Neural Cells ◽  
Chain Reaction ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Fluoxetine Treatment ◽  
Polymerase Chain

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.

scholarly journals Target of Rapamycin in Control of Autophagy: Puppet Master and Signal Integrator

2020 ◽  
Vol 21 (21) ◽  
pp. 8259
Author(s):  
Yosia Mugume ◽  
Zakayo Kazibwe ◽  
Diane C. Bassham
Keyword(s):  
Degradation Pathway ◽  
Target Of Rapamycin ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Photosynthetic Organisms ◽  
Downstream Effectors ◽  
Evolutionarily Conserved ◽  
Recent Developments ◽  
Stress Signals ◽  
And Function

The target of rapamycin (TOR) is an evolutionarily-conserved serine/threonine kinase that senses and integrates signals from the environment to coordinate developmental and metabolic processes. TOR senses nutrients, hormones, metabolites, and stress signals to promote cell and organ growth when conditions are favorable. However, TOR is inhibited when conditions are unfavorable, promoting catabolic processes such as autophagy. Autophagy is a macromolecular degradation pathway by which cells degrade and recycle cytoplasmic materials. TOR negatively regulates autophagy through phosphorylation of ATG13, preventing activation of the autophagy-initiating ATG1-ATG13 kinase complex. Here we review TOR complex composition and function in photosynthetic and non-photosynthetic organisms. We also review recent developments in the identification of upstream TOR activators and downstream effectors of TOR. Finally, we discuss recent developments in our understanding of the regulation of autophagy by TOR in photosynthetic organisms.

Role of New Chemotherapy Agents in Soft Tissue Sarcoma

2005 ◽  
Vol 3 (2) ◽  
pp. 198-205
Author(s):  
Margaret von Mehren
Keyword(s):  
Soft Tissue ◽  
Single Agent ◽  
Growth Factor Receptor ◽  
Soft Tissue Sarcomas ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Cell Cycle Activation ◽  
Metastatic Gist ◽  
Chemotherapy Agents

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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