scholarly journals Ubl4A is required for insulin-induced Akt plasma membrane translocation through promotion of Arp2/3-dependent actin branching

2015 ◽  
Vol 112 (31) ◽  
pp. 9644-9649 ◽  
Author(s):  
Yu Zhao ◽  
Yuting Lin ◽  
Honghong Zhang ◽  
Adriana Mañas ◽  
Wenwen Tang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Glycogen Synthesis ◽  
Membrane Translocation ◽  
Insulin Stimulation ◽  
Serine Threonine Kinase ◽  
Newborn Mice ◽  
Threonine Kinase ◽  
Cell Mobility ◽  
Close Proximity ◽  
Extracellular Stimuli

The serine-threonine kinase Akt is a key regulator of cell proliferation and survival, glucose metabolism, cell mobility, and tumorigenesis. Activation of Akt by extracellular stimuli such as insulin centers on the interaction of Akt with PIP3 on the plasma membrane, where it is subsequently phosphorylated and activated by upstream protein kinases. However, it is not known how Akt is recruited to the plasma membrane upon stimulation. Here we report that ubiquitin-like protein 4A (Ubl4A) plays a crucial role in insulin-induced Akt plasma membrane translocation. Ubl4A knockout newborn mice have defective Akt-dependent glycogen synthesis and increased neonatal mortality. Loss of Ubl4A results in the impairment of insulin-induced Akt translocation to the plasma membrane and activation. Akt binds actin-filaments and colocalizes with actin-related protein 2 and 3 (Arp2/3) complex in the membrane ruffles and lamellipodia. Ubl4A directly interacts with Arp2/3 to accelerate actin branching and networking, allowing Akt to be in close proximity to the plasma membrane for activation upon insulin stimulation. Our finding reveals a new mechanism by which Akt is recruited to the plasma membrane for activation, thereby providing a missing link in Akt signaling.

GSK-3 Inhibitors in Regulation and Controlling of Colon Carcinoma

2021 ◽  
Vol 22 ◽  
Author(s):  
Sitansu Sekhar Nanda ◽  
Md Imran Hossain ◽  
Heongkyu Ju ◽  
Dong Kee Yi
Keyword(s):  
Colon Carcinoma ◽  
Clinical Studies ◽  
Glycogen Synthesis ◽  
Morphological Examination ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Cellular Processes ◽  
Adenocarcinoma Cells ◽  
Membrane Bound

Background: GSK-3 inhibitors became a novel therapeutic agent treating cancer. There are so many uses of GSK-3 inhibitor for treating cancer like breast cancer, lung cancer, gastric cancer, and no pathological changes are shown by the morphological examination of GSK-3. Objectives: This review describes the recent affairs using GSK-3 inhibitors, mainly treating in colon carcinoma. The authorsAuthors have also shown the different mechanisms of different GSK-3 inhibitors for treating various cancers and proposed some mechanisms that can be useful for further research by GSK-3 inhibitors for various cancerscancer including colon carcinoma. Results: The majority of the cancers and pre-cancerous lesions are stimulated by the transformation of membrane-bound arachidonic acid (AA) to eicosanoids for the viability, proliferation, and spread of cancer. GSK-3 inhibitors can reinstate hostility to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) responsiveness in gastric adenocarcinoma cells. GSK-3, the final enzyme in glycogen synthesis, is a serine/threonine kinase that phosphorylates varied sequences that are more than a hundred in number, within proteins in an array of heterogeneous pathways. It is an essential module of an exceptionally huge number of cellular processes, a fundamental role in many metabolic processes and diseases. Many patients achieve long term remission with outstanding survival diagnosed with colon cancer through it. Conclusion: Before the extensive application of these proposed mechanisms of GSK-3 inhibitor, further evaluation and clinical studies are needed. After doing the appropriate clinical studies and morphological examination, it can be appropriate for extensive application.

scholarly journals Ulk1 plays a critical role in the autophagic clearance of mitochondria and ribosomes during reticulocyte maturation

Blood ◽  
2008 ◽  
Vol 112 (4) ◽  
pp. 1493-1502 ◽  
Author(s):  
Mondira Kundu ◽  
Tullia Lindsten ◽  
Chia-Ying Yang ◽  
Junmin Wu ◽  
Fangping Zhao ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Critical Role ◽  
Serine Threonine Kinase ◽  
Newborn Mice ◽  
Atp Production ◽  
Threonine Kinase ◽  
Selective Elimination ◽  
Reticulocyte Maturation ◽  
Erythroid Maturation

Abstract Production of a red blood cell's hemoglobin depends on mitochondrial heme synthesis. However, mature red blood cells are devoid of mitochondria and rely on glycolysis for ATP production. The molecular basis for the selective elimination of mitochondria from mature red blood cells remains controversial. Recent evidence suggests that clearance of both mitochondria and ribosomes, which occurs in reticulocytes following nuclear extrusion, depends on autophagy. Here, we demonstrate that Ulk1, a serine threonine kinase with homology to yeast atg1p, is a critical regulator of mitochondrial and ribosomal clearance during the final stages of erythroid maturation. However, in contrast to the core autophagy genes such as atg5 and atg7, expression of ulk1 is not essential for induction of macroautophagy in response to nutrient deprivation or for survival of newborn mice. Together, these data suggest that the ATG1 homologue, Ulk1, is a component of the selective autophagy machinery that leads to the elimination of organelles in erythroid cells rather that an essential mechanistic component of autophagy.

scholarly journals Requirement for Activation of the Serine-Threonine Kinase Akt (Protein Kinase B) in Insulin Stimulation of Protein Synthesis but Not of Glucose Transport

1998 ◽  
Vol 18 (7) ◽  
pp. 3708-3717 ◽  
Author(s):  
Tadahiro Kitamura ◽  
Wataru Ogawa ◽  
Hiroshi Sakaue ◽  
Yasuhisa Hino ◽  
Shoji Kuroda ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Kinase ◽  
Cho Cells ◽  
Protein Kinase B ◽  
Insulin Stimulation ◽  
Serine Threonine Kinase ◽  
S6 Kinase ◽  
Threonine Kinase ◽  
Downstream Effector ◽  
Stimulation Of

ABSTRACT A wide variety of biological activities including the major metabolic actions of insulin is regulated by phosphatidylinositol (PI) 3-kinase. However, the downstream effectors of the various signaling pathways that emanate from PI 3-kinase remain unclear. Akt (protein kinase B), a serine-threonine kinase with a pleckstrin homology domain, is thought to be one such downstream effector. A mutant Akt (Akt-AA) in which the phosphorylation sites (Thr308 and Ser473) targeted by growth factors are replaced by alanine has now been shown to lack protein kinase activity and, when overexpressed in CHO cells or 3T3-L1 adipocytes with the use of an adenovirus vector, to inhibit insulin-induced activation of endogenous Akt. Akt-AA thus acts in a dominant negative manner in intact cells. Insulin-stimulated protein synthesis, which is sensitive to wortmannin, a pharmacological inhibitor of PI 3-kinase, was abolished by overexpression of Akt-AA without an effect on amino acid transport into the cells, suggesting that Akt is required for insulin-stimulated protein synthesis. Insulin activation of p70 S6 kinase was inhibited by ∼75% in CHO cells and ∼30% in 3T3-L1 adipocytes, whereas insulin-induced activation of endogenous Akt was inhibited by 80 to 95%, by expression of Akt-AA. Thus, Akt activity appears to be required, at least in part, for insulin stimulation of p70 S6 kinase. However, insulin-stimulated glucose uptake in both CHO cells and 3T3-L1 adipocytes was not affected by overexpression of Akt-AA, suggesting that Akt is not required for this effect of insulin. These data indicate that Akt acts as a downstream effector in some, but not all, of the signaling pathways downstream of PI 3-kinase.

scholarly journals Autoregulation of the Raf-1 serine/threonine kinase

1998 ◽  
Vol 95 (16) ◽  
pp. 9214-9219 ◽  
Author(s):  
Richard E. Cutler ◽  
Robert M. Stephens ◽  
Misty R. Saracino ◽  
Deborah K. Morrison
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase C ◽  
Regulatory Region ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Rich Domain ◽  
Kinase C ◽  
Evolutionarily Conserved ◽  
Phosphorylation Event ◽  
Cysteine Rich Domain

The Raf-1 serine/threonine kinase is a key protein involved in the transmission of many growth and developmental signals. In this report, we show that autoinhibition mediated by the noncatalytic, N-terminal regulatory region of Raf-1 is an important mechanism regulating Raf-1 function. The inhibition of the regulatory region occurs, at least in part, through binding interactions involving the cysteine-rich domain. Events that disrupt this autoinhibition, such as mutation of the cysteine-rich domain or a mutation mimicking an activating phosphorylation event (Y340D), alleviate the repression of the regulatory region and increase Raf-1 activity. Based on the striking similarites between the autoregulation of the serine/threonine kinases protein kinase C, Byr2, and Raf-1, we propose that relief of autorepression and activation at the plasma membrane is an evolutionarily conserved mechanism of kinase regulation.

scholarly journals Targeted Disruption of the Mouse PAS Domain Serine/Threonine Kinase PASKIN

2003 ◽  
Vol 23 (19) ◽  
pp. 6780-6789 ◽  
Author(s):  
Dörthe M. Katschinski ◽  
Hugo H. Marti ◽  
Klaus F. Wagner ◽  
Junpei Shibata ◽  
Katrin Eckhardt ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Glycogen Synthesis ◽  
Embryonic Stem ◽  
Cell Types ◽  
Protein Phosphatase 1 ◽  
Regulatory Subunit ◽  
Dependent Manner ◽  
Pas Domain ◽  
Serine Threonine Kinase ◽  
Threonine Kinase

ABSTRACT PASKIN is a novel mammalian serine/threonine kinase containing two PAS (Per-Arnt-Sim) domains. PASKIN is related to the Rhizobium oxygen sensor protein FixL and to AMP-regulated kinases. Like FixL, the sensory PAS domain of PASKIN controls the kinase activity by autophosphorylation in a (unknown) ligand-dependent manner. In Saccharomyces cerevisiae, the two PASKIN orthologues PSK1 and PSK2 phosphorylate three translation factors and two enzymes involved in glycogen synthesis, thereby coordinately regulating protein synthesis and glycolytic flux. To elucidate the function of mammalian PASKIN, we inactivated the mouse Paskin gene by homologous recombination in embryonic stem cells. Paskin −/− mice showed normal development, growth, and reproduction. The targeted integration of a lacZ reporter gene allowed the identification of the cell types expressing mouse PASKIN. Surprisingly, PASKIN expression is strongly upregulated in postmeiotic germ cells during spermatogenesis. However, fertility and sperm production and motility were not affected by the PASKIN knockout. The Ppp1r7 gene encoding Sds22, a regulatory subunit of protein phosphatase 1, shares the promoter region with the Paskin gene, pointing towards a common transcriptional regulation. Indeed, Sds22 colocalized with the cell types expressing PASKIN in vivo, suggesting a functional role of protein phosphatase-1 in the regulation of PASKIN autophosphorylation.

WNK3 abrogates the NEDD4-2-mediated inhibition of the renal Na+-Cl− cotransporter

2014 ◽  
Vol 307 (3) ◽  
pp. F275-F286 ◽  
Author(s):  
Dagmara Lagnaz ◽  
Juan Pablo Arroyo ◽  
María Chávez-Canales ◽  
Norma Vázquez ◽  
Federica Rizzo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Xenopus Laevis ◽  
Inhibitory Effect ◽  
Kinase Domain ◽  
Hek293 Cells ◽  
Xenopus Laevis Oocytes ◽  
Glutathione S Transferase ◽  
Serine Threonine Kinase ◽  
Ubiquitin Protein Ligase ◽  
Threonine Kinase

The serine/threonine kinase WNK3 and the ubiquitin-protein ligase NEDD4-2 are key regulators of the thiazide-sensitive Na+-Cl− cotransporter (NCC), WNK3 as an activator and NEDD2-4 as an inhibitor. Nedd4-2 was identified as an interacting partner of WNK3 through a glutathione- S-transferase pull-down assay using the N-terminal domain of WNK3, combined with LC-MS/MS analysis. This was validated by coimmunoprecipitation of WNK3 and NEDD4-2 expressed in HEK293 cells. Our data also revealed that the interaction between Nedd4-2 and WNK3 does not involve the PY-like motif found in WNK3. The level of WNK3 ubiquitylation did not change when NEDD4-2 was expressed in HEK293 cells. Moreover, in contrast to SGK1, WNK3 did not phosphorylate NEDD4-2 on S222 or S328. Coimmunoprecipitation assays showed that WNK3 does not regulate the interaction between NCC and NEDD4-2. Interestingly, in Xenopus laevis oocytes, WNK3 was able to recover the SGK1-resistant NEDD4-2 S222A/S328A-mediated inhibition of NCC and further activate NCC. Furthermore, elimination of the SPAK binding site in the kinase domain of WNK3 (WNK3-F242A, which lacks the capacity to bind the serine/threonine kinase SPAK) prevented the WNK3 NCC-activating effect, but not the Nedd4-2-inhibitory effect. Together, these results suggest that a novel role for WNK3 on NCC expression at the plasma membrane, an effect apparently independent of the SPAK kinase and the aldosterone-SGK1 pathway.

scholarly journals A Novel AAK1 Splice Variant Functions at Multiple Steps of the Endocytic Pathway

2007 ◽  
Vol 18 (7) ◽  
pp. 2698-2706 ◽  
Author(s):  
Davin M. Henderson ◽  
Sean D. Conner
Keyword(s):  
Plasma Membrane ◽  
Kinase Activity ◽  
Endocytic Pathway ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
C Terminus ◽  
Long Form ◽  
Endosomal Pathway ◽  
Affinity Interaction

Phosphorylation is a critical step in regulating receptor transport through the endocytic pathway. AAK1 is a serine/threonine kinase that is thought to coordinate the recruitment of AP-2 to receptors containing tyrosine-based internalization motifs by phosphorylating the μ2 subunit. Here we have identified a long form of AAK1 (AAK1L) that contains an extended C-terminus that encodes an additional clathrin-binding domain (CBD2) consisting of multiple low-affinity interaction motifs. Protein interaction studies demonstrate that AAK1L CBD2 directly binds clathrin. However, in vitro kinase assays reveal little difference between AAK1 isoforms in their basal or clathrin-stimulated kinase activity toward the AP-2 μ2 subunit. However, overexpression of AAK1L CBD2 impairs transferrin endocytosis, confirming an endocytic role for AAK1. Surprisingly, CBD2 overexpression or AAK1 depletion by RNA interference significantly impairs transferrin recycling from the early/sorting endosome. These observations suggest that AAK1 functions at multiple steps of the endosomal pathway by regulating transferrin internalization and its rapid recycling back to the plasma membrane from early/sorting endosome.

scholarly journals Multifaceted Roles of GSK-3 in Cancer and Autophagy-Related Diseases

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Romina Mancinelli ◽  
Guido Carpino ◽  
Simonetta Petrungaro ◽  
Caterina Loredana Mammola ◽  
Luana Tomaipitinca ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Cancer Progression ◽  
Liver Diseases ◽  
Glycogen Synthesis ◽  
Molecular Target ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Natural Substances ◽  
Age Related ◽  
Inhibit Tumor Cell Proliferation

GSK-3 is a ubiquitously expressed serine/threonine kinase existing as GSK-3αand GSK-3βisoforms, both active under basal conditions and inactivated upon phosphorylation by different upstream kinases. Initially discovered as a regulator of glycogen synthesis, GSK-3 is also involved in several signaling pathways controlling many different key functions. Here, we discuss recent advances regarding (i) GSK-3 structure, function, regulation, and involvement in several cancers, including hepatocarcinoma, cholangiocarcinoma, breast cancer, prostate cancer, leukemia, and melanoma (active GSK-3 has been shown to induce apoptosis in some cases or inhibit apoptosis in other cases and to induce cancer progression or inhibit tumor cell proliferation, suggesting that different GSK-3 modulators may address different specific targets); (ii) GSK-3 involvement in autophagy modulation, reviewing signaling pathways involved in neurodegenerative and liver diseases; (iii) GSK-3 role in oxidative stress and autophagic cell death, focusing on liver injury; (iv) GSK-3 as a possible therapeutic target of natural substances and synthetic inhibitors in many diseases; and (v) GSK-3 role as modulator of mammalian aging, related to metabolic alterations characterizing senescent cells and age-related diseases. Studies summarized here underline the GSK-3 multifaceted role and indicate such kinase as a molecular target in different pathologies, including diseases associated with autophagy dysregulation.

scholarly journals Extracellular ATP Causes ROCK I-dependent Bleb Formation in P2X7-transfected HEK293 Cells

2003 ◽  
Vol 14 (7) ◽  
pp. 2655-2664 ◽  
Author(s):  
Anna Morelli ◽  
Paola Chiozzi ◽  
Anna Chiesa ◽  
Davide Ferrari ◽  
Juana M. Sanz ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Extracellular Atp ◽  
Hek293 Cells ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Membrane Blebbing ◽  
Wide Range ◽  
Dependent Cell ◽  
Bleb Formation ◽  
Early Effects

The P2X7 ATP receptor mediates the cytotoxic effect of extracellular ATP. P2X7-dependent cell death is heralded by dramatic plasma membrane bleb formation. Membrane blebbing is a complex phenomenon involving as yet poorly characterized intracellular pathways. We have investigated the effect of extracellular ATP on HEK293 cells transfected with the cytotoxic/pore-forming P2X7 receptor. Addition of ATP to P2X7-transfected, but not to wt P2X7-less, HEK293 cells caused massive membrane blebbing within 1–2 min. UTP, a nucleotide incapable of activating P2X7, had no early effects on cell shape and bleb formation. Bleb formation triggered by ATP was reversible and required extracellular Ca2+ and an intact cytoskeleton. Furthermore, it was completely prevented by preincubation with the P2X blocker oxidized ATP. It was recently observed that the ROCK protein is a key determinant of bleb formation. Preincubation of HEK293-P2X7 cells with the ROCK blocker Y-27632 completely prevented P2X7-dependent blebbing. Although ATP triggered cleavage of the ROCK I isoform in P2X7-transfected HEK293 cells, the wide range caspase inhibitor z-VAD-fluoromethylketone had no effect. These observations suggest that P2X7-dependent plasma membrane blebbing depends on the activation of the serine/threonine kinase ROCK I.

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