scholarly journals α1AMP-Activated Protein Kinase Protects against Lipopolysaccharide-Induced Endothelial Barrier Disruption via Junctional Reinforcement and Activation of the p38 MAPK/HSP27 Pathway

2020 ◽  
Vol 21 (15) ◽  
pp. 5581
Author(s):  
Marine Angé ◽  
Diego Castanares-Zapatero ◽  
Julien De Poortere ◽  
Cécile Dufeys ◽  
Guillaume E. Courtoy ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Actin Cytoskeleton ◽  
P38 Mapk ◽  
Connexin 43 ◽  
Molecular Mechanisms ◽  
Small Gtpase ◽  
Endothelial Barrier ◽  
Barrier Disruption ◽  
Cellular Junctions

Vascular hyperpermeability is a determinant factor in the pathophysiology of sepsis. While, AMP-activated protein kinase (AMPK) is known to play a role in maintaining endothelial barrier function in this condition. Therefore, we investigated the underlying molecular mechanisms of this protective effect. α1AMPK expression and/or activity was modulated in human dermal microvascular endothelial cells using either α1AMPK-targeting small interfering RNA or the direct pharmacological AMPK activator 991, prior to lipopolysaccharide (LPS) treatment. Western blotting was used to analyze the expression and/or phosphorylation of proteins that compose cellular junctions (zonula occludens-1 (ZO-1), vascular endothelial cadherin (VE-Cad), connexin 43 (Cx43)) or that regulate actin cytoskeleton (p38 MAPK; heat shock protein 27 (HSP27)). Functional endothelial permeability was assessed by in vitro Transwell assays, and quantification of cellular junctions in the plasma membrane was assessed by immunofluorescence. Actin cytoskeleton remodeling was evaluated through actin fluorescent staining. We consequently demonstrate that α1AMPK deficiency is associated with reduced expression of CX43, ZO-1, and VE-Cad, and that the drastic loss of CX43 is likely responsible for the subsequent decreased expression and localization of ZO-1 and VE-Cad in the plasma membrane. Moreover, α1AMPK activation by 991 protects against LPS-induced endothelial barrier disruption by reinforcing cortical actin cytoskeleton. This is due to a mechanism that involves the phosphorylation of p38 MAPK and HSP27, which is nonetheless independent of the small GTPase Rac1. This results in a drastic decrease of LPS-induced hyperpermeability. We conclude that α1AMPK activators that are suitable for clinical use may provide a specific therapeutic intervention that limits sepsis-induced vascular leakage.

scholarly journals The TGFβ-induced phosphorylation and activation of p38 mitogen-activated protein kinase is mediated by MAP3K4 and MAP3K10 but not TAK1

Open Biology ◽  
2013 ◽  
Vol 3 (6) ◽  
pp. 130067 ◽  
Author(s):  
Gopal P. Sapkota
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Transforming Growth Factor Beta ◽  
Molecular Mechanisms ◽  
Epithelial To Mesenchymal Transition ◽  
Transforming Growth Factor ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Phosphorylation ◽  
Mesenchymal Transition ◽  
Mitogen Activated Protein

The signalling pathways downstream of the transforming growth factor beta (TGFβ) family of cytokines play critical roles in all aspects of cellular homeostasis. The phosphorylation and activation of p38 mitogen-activated protein kinase (MAPK) has been implicated in TGFβ-induced epithelial-to-mesenchymal transition and apoptosis. The precise molecular mechanisms by which TGFβ cytokines induce the phosphorylation and activation of p38 MAPK are unclear. In this study, I demonstrate that TGFβ-activated kinase 1 (TAK1/MAP3K7) does not play a role in the TGFβ-induced phosphorylation and activation of p38 MAPK in MEFs and HaCaT keratinocytes. Instead, RNAi -mediated depletion of MAP3K4 and MAP3K10 results in the inhibition of the TGFβ-induced p38 MAPK phosphorylation. Furthermore, the depletion of MAP3K10 from cells homozygously knocked-in with a catalytically inactive mutant of MAP3K4 completely abolishes the TGFβ-induced phosphorylation of p38 MAPK, implying that among MAP3Ks, MAP3K4 and MAP3K10 are sufficient for mediating the TGFβ-induced activation of p38 MAPK.

scholarly journals Yeast actin cytoskeleton mutants accumulate a new class of Golgi-derived secretary vesicle.

1997 ◽  
Vol 8 (8) ◽  
pp. 1481-1499 ◽  
Author(s):  
J Mulholland ◽  
A Wesp ◽  
H Riezman ◽  
D Botstein
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Biochemical Analysis ◽  
Small Gtpase ◽  
Secretory Vesicles ◽  
Cytoskeleton Organization ◽  
New Class ◽  
Actin Cytoskeleton Organization ◽  
Vectorial Transport

Many yeast actin cytoskeleton mutants accumulate large secretory vesicles and exhibit phenotypes consistent with defects in polarized growth. This, together with actin's polarized organization, has suggested a role for the actin cytoskeleton in the vectorial transport of late secretory vesicles to the plasma membrane. By using ultrastructural and biochemical analysis, we have characterized defects manifested by mutations in the SLA2 gene (also known as the END4 gene), previously found to affect both the organization of the actin cytoskeleton and endocytosis in yeast. Defects in cell wall morphology, accumulated vesicles, and protein secretion kinetics were found in sla2 mutants similar to defects found in act1 mutants. Vesicles that accumulate in the sla2 and act1 mutants are immunoreactive with antibodies directed against the small GTPase Ypt1p but not with antibodies directed against the homologous Sec4p found on classical "late" secretory vesicles. In contrast, the late-acting secretory mutants sec1-1 and sec6-4 are shown to accumulate anti-Sec4p-positive secretory vesicles as well as vesicles that are immunoreactive with antibodies directed against Ypt1p. The late sec mutant sec4-8 is also shown to accumulate Ypt1p-containing vesicles and to exhibit defects in actin cytoskeleton organization. These results indicate the existence of at least two classes of morphologically similar, late secretory vesicles (associated with Ypt1p+ and Sec4p+, respectively), one of which appears to accumulate when the actin cytoskeleton is disorganized.

scholarly journals Phospholipase D Activity Regulates Integrin-mediated Cell Spreading and Migration by Inducing GTP-Rac Translocation to the Plasma Membrane

2008 ◽  
Vol 19 (7) ◽  
pp. 3111-3123 ◽  
Author(s):  
Young Chan Chae ◽  
Jung Hwan Kim ◽  
Kyung Lock Kim ◽  
Hyun Wook Kim ◽  
Hye Young Lee ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Phospholipase D ◽  
Molecular Mechanisms ◽  
Direct Interaction ◽  
Cell Spreading ◽  
Small Gtpase ◽  
General Mechanism ◽  
Downstream Target ◽  
P21 Activated Kinase ◽  
And Migration

Small GTPase Rac is a crucial regulator of actin cytoskeletal rearrangement, and it plays an important role in cell spreading, migration, mitogenesis, phagocytosis, superoxide generation, and axonal growth. It is generally accepted that Rac activity is regulated by the guanosine triphosphate (GTP)/guanosine diphosphate (GDP) cycle. But, it is suggested that in addition to Rac-GTP loading, membrane localization is required for the initiation of downstream effector signaling. However, the molecular mechanisms that control the targeting of GTP-Rac to the plasma membrane remain largely unknown. Here, we have uncovered a signaling pathway linking phospholipase D (PLD) to the localized functions of Rac1. We show that PLD product phosphatidic acid (PA) acts as a membrane anchor of Rac1. The C-terminal polybasic motif of Rac1 is responsible for direct interaction with PA, and Rac1 mutated in this region is incapable of translocating to the plasma membrane and of activating downstream target p21-activated kinase upon integrin activation. Finally, we show that PA induces dissociation of Rho-guanine nucleotide dissociation inhibitor from Rac1 and that PA-mediated Rac1 localization is important for integrin-mediated lamellipodia formation, cell spreading, and migration. These results provide a novel molecular mechanism for the GTP-Rac1 localization through the elevating PLD activity, and they suggest a general mechanism for diverse cellular functions that is required localized Rac activation.

scholarly journals Competitive binding of Rab21 and p120RasGAP to integrins regulates receptor traffic and migration

2011 ◽  
Vol 194 (2) ◽  
pp. 291-306 ◽  
Author(s):  
Anja Mai ◽  
Stefan Veltel ◽  
Teijo Pellinen ◽  
Artur Padzik ◽  
Eleanor Coffey ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Motility ◽  
Molecular Mechanisms ◽  
Regulatory Mechanism ◽  
Competitive Binding ◽  
Small Gtpase ◽  
Rab Gtpases ◽  
Endocytic Machinery ◽  
And Migration ◽  
Α Subunits

Integrin trafficking from and to the plasma membrane controls many aspects of cell behavior including cell motility, invasion, and cytokinesis. Recruitment of integrin cargo to the endocytic machinery is regulated by the small GTPase Rab21, but the detailed molecular mechanisms underlying integrin cargo recruitment are yet unknown. Here we identify an important role for p120RasGAP (RASA1) in the recycling of endocytosed α/β1-integrin heterodimers to the plasma membrane. Silencing of p120RasGAP attenuated integrin recycling and augmented cell motility. Mechanistically, p120RasGAP interacted with the cytoplasmic domain of integrin α-subunits via its GAP domain and competed with Rab21 for binding to endocytosed integrins. This in turn facilitated exit of the integrin from Rab21- and EEA1-positive endosomes to drive recycling. Our results assign an unexpected role for p120RasGAP in the regulation of integrin traffic in cancer cells and reveal a new concept of competitive binding of Rab GTPases and GAP proteins to receptors as a regulatory mechanism in trafficking.

scholarly journals Epstein–Barr virus BDLF2–BMRF2 complex affects cellular morphology

2009 ◽  
Vol 90 (6) ◽  
pp. 1440-1449 ◽  
Author(s):  
Jens-Bernhard Loesing ◽  
Stefano Di Fiore ◽  
Klaus Ritter ◽  
Rainer Fischer ◽  
Michael Kleines
Keyword(s):  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Actin Cytoskeleton ◽  
Epstein Barr Virus ◽  
Active Form ◽  
Small Gtpase ◽  
Cellular Morphology ◽  
Subcellular Compartment ◽  
Barr Virus ◽  
Epstein Barr

Herpesvirus glycoproteins often form specific heterodimers that can fulfil functions that cannot be carried out by either of the partners acting alone. This study showed that interactions between the Epstein–Barr virus (EBV) multi-spanning transmembrane envelope protein BMRF2 and type II membrane protein BDLF2 influence the way in which these proteins are trafficked in the cell, and hence the subcellular compartment in which they accumulate. When expressed transiently in mammalian cells, BDLF2 accumulated in the endoplasmic reticulum (ER), whereas BMRF2 accumulated in the ER and Golgi apparatus. However, when the two proteins were co-expressed, BDLF2 was transported with BMRF2 to the Golgi apparatus and from there to the plasma membrane, where the proteins co-localized extensively. The distribution of the two proteins at the plasma membrane was reproducibly associated with dramatic changes in cellular morphology, including the formation of enlarged membrane protrusions and cellular processes whose adhesion extremities were organized by the actin cytoskeleton. A dominant-active form of the small GTPase RhoA was epistatic to this morphological phenotype, suggesting that RhoA is a central component of the signalling pathway that reorganizes the cytoskeleton in response to BDLF2–BMRF2. It was concluded that EBV produces a glycoprotein heterodimer that induces changes in cellular morphology through reorganization of the actin cytoskeleton and may facilitate virion spread between cells.

scholarly journals Actin Cytoskeleton Rest Stops Regulate Anterograde Traffic of Connexin 43 Vesicles to the Plasma Membrane

2012 ◽  
Vol 110 (7) ◽  
pp. 978-989 ◽  
Author(s):  
James W. Smyth ◽  
Jacob M. Vogan ◽  
Pranali J. Buch ◽  
Shan-Shan Zhang ◽  
Tina S. Fong ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Connexin 43

scholarly journals Protein Kinase G and p38 MAPK in H 2 O 2 ‐induced pulmonary endothelial barrier dysfunction

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Otgonchimeg Rentsendorj ◽  
Laura E. Servinsky ◽  
Larissa A. Shimoda ◽  
Aigul Moldobaeva ◽  
Tamara Mirzapoiazova ◽  
...  
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Endothelial Barrier ◽  
Protein Kinase G ◽  
Barrier Dysfunction ◽  
Endothelial Barrier Dysfunction

Stimulation of protein kinase C pathway mediates endocytosis of human nongastric H+-K+-ATPase, ATP1AL1

2002 ◽  
Vol 283 (2) ◽  
pp. F335-F343 ◽  
Author(s):  
J. Reinhardt ◽  
M. Kosch ◽  
M. Lerner ◽  
H. Bertram ◽  
D. Lemke ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Phorbol Esters ◽  
Ion Pump ◽  
Membrane Expression ◽  
Kinase C ◽  
Plasma Membrane Expression ◽  
Functional Inactivation

The human nongastric H+-K+-ATPase, ATP1AL1, shown to reabsorb K+ in exchange for H+ or Na+, is localized in the luminal plasma membrane of renal epithelial cells. It is presumed that renal H+-K+-ATPases can be regulated by endocytosis. However, little is known about the molecular mechanisms that control plasma membrane expression of renal H+-K+-ATPases. In our study, activation of protein kinase C (PKC) using phorbol esters (phorbol 12-myristate 13-acetate) leads to clathrin-dependent internalization and intracellular accumulation of the ion pump in stably transfected Madin-Darby canine kidney cells. Functional inactivation of the H+-K+-ATPase by PKC activation is shown by intracellular pH measurements. Proton extrusion capacity of ATP1AL1-transfected cells is drastically reduced after phorbol 12-myristate 13-acetate incubation and can be prevented with the PKC blocker bisindolylmaleimide. Ion pump internalization and inactivation are specifically mediated by the PKC pathway, whereas activation of the protein kinase A pathway has no influence. Our results show that the nongastric H+-K+-ATPase is a specific target for the PKC pathway. Therefore, PKC-mediated phosphorylation is a potential regulatory mechanism for apical nongastric H+-K+-ATPase plasma membrane expression.

scholarly journals Eicosapentaenoic Acid (EPA) Modulates Glucose Metabolism by Targeting AMP-Activated Protein Kinase (AMPK) Pathway

2019 ◽  
Vol 20 (19) ◽  
pp. 4751 ◽  
Author(s):  
Nami Kim ◽  
Mi Sun Kang ◽  
Miso Nam ◽  
Shin Ae Kim ◽  
Geum-Sook Hwang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Glucose Transporter ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Omega 3 ◽  
Beneficial Effects ◽  
Calcium Calmodulin Dependent ◽  
Amp Activated Protein Kinase

EPA, an omega-3 polyunsaturated fatty acid, exerts beneficial effects on human health. However, the molecular mechanisms underlying EPA function are poorly understood. The object was to illuminate molecular mechanism underlying EPA’s role. Here, 1H-NMR-based metabolic analysis showed enhanced branched-chain amino acids (BCAAs) and lactate following EPA treatment in skeletal muscle cells. EPA regulated mitochondrial oxygen consumption rate. Furthermore, EPA induced calcium/calmodulin-dependent protein kinase kinase (CaMKK) through the generation of intracellular calcium. This induced the phosphorylation of AMP-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase (p38 MAPK) that led to glucose uptake, and the translocation of glucose transporter type 4 (GLUT4) in muscles. In conclusion, EPA exerts benign effects on glucose through the activation of AMPK-p38 MAPK signaling pathways in skeletal muscles.

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