scholarly journals Hormonal regulation of focal adhesions in bovine adrenocortical cells: induction of paxillin dephosphorylation by adrenocorticotropic hormone

1998 ◽  
Vol 332 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Isabelle VILGRAIN ◽  
Anna CHINN ◽  
Isabelle GAILLARD ◽  
Edmond M. CHAMBAZ ◽  
Jean-Jacques FEIGE
Keyword(s):  
Tyrosine Phosphorylation ◽  
Hormonal Regulation ◽  
Adrenocorticotropic Hormone ◽  
Focal Adhesions ◽  
Insoluble Fraction ◽  
Dependent Manner ◽  
Sodium Orthovanadate ◽  
Adrenocortical Cells ◽  
Acth Challenge ◽  
Phosphatase Inhibitor

A study of bovine adrenocortical cell shape on adrenocorticotropic hormone (ACTH) challenge showed that the cells round up and develop arborized processes. This effect was found to be (1) specific for ACTH because angiotensin II and basic fibroblast growth factor have no effect; (2) mediated by a cAMP-dependent pathway because forskolin reproduces the effect of the hormone; (3) inhibited by sodium orthovanadate, a phosphotyrosine phosphatase inhibitor, but unchanged by okadaic acid, a serine/threonine phosphatase inhibitor; and (4) correlated with a complete loss of focal adhesions. Biochemical studies of the focal-adhesion-associated proteins showed that pp125fak, vinculin (110 kDa) and paxillin (70 kDa) were detected in the Triton X-100-insoluble fraction from adrenocortical cells. During cell adhesion on fibronectin as substratum, two major phosphotyrosine-containing proteins of molecular masses 125 and 68 kDa were immunodetected in the same fraction. A dramatic decrease in the extent of tyrosine phosphorylation of these proteins was observed within 60 min after treatment with ACTH. No change in pp125fak tyrosine phosphorylation nor in Src activity was detected. In contrast, paxillin was found to be tyrosine-dephosphorylated in a time-dependent manner in ACTH-treated cells. Sodium orthovanadate completely prevented the effect of ACTH. These observations suggest a possible role for phosphotyrosine phosphatases in hormone-dependent cellular regulatory processes.

scholarly journals Pyk2- and Src-Dependent Tyrosine Phosphorylation of PDK1 Regulates Focal Adhesions

2003 ◽  
Vol 23 (22) ◽  
pp. 8019-8029 ◽  
Author(s):  
Yoshihiro Taniyama ◽  
David S. Weber ◽  
Petra Rocic ◽  
Lula Hilenski ◽  
Marjorie L. Akers ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Tyrosine Phosphorylation ◽  
Adhesion Formation ◽  
Focal Adhesions ◽  
Dependent Manner ◽  
Critical Function ◽  
Focal Adhesion Formation ◽  
Dependent Protein ◽  
And Migration

ABSTRACT 3-Phosphoinositide-dependent protein kinase 1 (PDK1) is a signal integrator that activates the AGC superfamily of serine/threonine kinases. PDK1 is phosphorylated on tyrosine by oxidants, although its regulation by agonists that stimulate G-protein-coupled receptor signaling pathways and the physiological consequences of tyrosine phosphorylation in this setting have not been fully identified. We found that angiotensin II stimulates the tyrosine phosphorylation of PDK1 in vascular smooth muscle in a calcium- and c-Src-dependent manner. The calcium-activated tyrosine kinase Pyk2 acts as a scaffold for Src-dependent phosphorylation of PDK1 on Tyr9, which permits phosphorylation of Tyr373 and -376 by Src. This critical function of Pyk2 is further supported by the observation that Pyk2 and tyrosine-phosphorylated PDK1 colocalize in focal adhesions after angiotensin II stimulation. Importantly, infection of smooth muscle cells with a Tyr9 mutant of PDK1 inhibits angiotensin II-induced tyrosine phosphorylation of paxillin and focal adhesion formation. These observations identify a novel interaction between PDK1 and Pyk2 that regulates the integrity of focal adhesions, which are major compartments for integrating signals for cell growth, apoptosis, and migration.

The phosphotyrosine phosphatase inhibitor vanadyl hydroperoxide induces morphological alterations, cytoskeletal rearrangements and increased adhesiveness in rat neutrophil leucocytes

1993 ◽  
Vol 106 (3) ◽  
pp. 891-901 ◽  
Author(s):  
P.A. Bennett ◽  
R.J. Dixon ◽  
S. Kellie
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Morphological Changes ◽  
Shape Change ◽  
Alternative Pathway ◽  
Tyrosine Phosphatase ◽  
Cellular Protein ◽  
Dependent Manner ◽  
Morphological Alterations ◽  
Phosphatase Inhibitor

The functional consequences of treating rat neutrophils with the potent tyrosine phosphatase inhibitor vanadyl hydroperoxide (pervanadate) has been investigated. Pervanadate induced rapid increases in cellular protein phosphotyrosine content in a dose-dependent manner. This treatment also resulted in a change in morphology of the cells from a rounded to a polarised morphology, with many cells exhibiting uropods, pseudopodia and increased membrane activity. Pervanadate induced a transient actin polymerisation and reorganisation similar to that in agonist-stimulated cells. The pervanadate-induced increases in tyrosine phosphorylation, shape change and actin polymerisation were inhibited by the tyrosine kinase inhibitors tyrphostin and erbstatin, indicating that these phenomena were mediated by the constitutive activity of cellular tyrosine kinases. Double fluorescence experiments demonstrated that there was a co-localisation of tyrosine phosphorylated proteins with F-actin in both pervanadate- and agonist-stimulated neutrophils. Pervanadate also induced spreading of neutrophils on tissue culture substrata with concurrent changes in F-actin localisation including unusual F-actin-containing structures. These results demonstrate that morphological changes and cytoskeletal reorganisation in neutrophils are regulated by tyrosine phosphorylation, and that inhibition of tyrosine phosphatase activity in neutrophils is sufficient to activate motile machinery of these cells. These results suggest that an alternative pathway involved in neutrophil stimulation might be via inhibition of endogenous tyrosine phosphatases rather than activation of tyrosine kinases.

Immune activation and psychoneurogenic stress modulate corticosterone-releasing effects of lymphokines and ACTH

1988 ◽  
Vol 255 (5) ◽  
pp. R839-R845 ◽  
Author(s):  
I. Torres-Aleman ◽  
I. Barasoain ◽  
J. Borrell ◽  
C. Guaza
Keyword(s):  
Immune System ◽  
Immune Activation ◽  
Adrenocorticotropic Hormone ◽  
Adrenocortical Cells ◽  
Acth Challenge ◽  
In Vitro Sensitivity ◽  
Corticosterone Response ◽  
Corticosterone Release ◽  
Pituitary Adrenal Axis

Possible modulatory effects of psychoneurogenic stress and endotoxin-induced immune activation on the in vitro corticosterone-releasing effects of lymphokine-containing supernatants (LCS) and adrenocorticotropic hormone (ACTH) were studied in rats. We have found that activation of the immune system by endotoxin increases the in vitro sensitivity of the adrenocortical cells to LCS and ACTH. In addition, we found that psychoneurogenic stress not only produced an increase of in vitro adrenal sensitivity to ACTH, but it also enhanced the release of corticosterone after perfusion of LCS. A synergistic interaction between ACTH and LCS was observed in all experimental groups of animals studied. An increased adrenal sensitivity to LCS and ACTH after stress or immune activation might have a functional significance, since the adrenal cortex is a major site in the response of the organism to alterations in the homeostatic balance. On the other hand, the temporal pattern of in vitro corticosterone release after LCS was different in all groups under study compared with that observed after ACTH challenge. LCS elicited a more rapid corticosterone response that lasted for a shorter time than after giving ACTH. These latter results suggest that different mechanisms may underlie the effects of LCS and ACTH on adrenal corticosteroidogenesis. In conclusion, the present findings further reinforce the existence of possible physiologically relevant interactions between the immune system and the pituitary-adrenal axis.

State of hormonal regulation in experimental animals exposed to noise and vibration

2020 ◽  
pp. 680-681
Author(s):  
A. V. Lizarev ◽  
V. A. Pankov
Keyword(s):  
Blood Plasma ◽  
Hormonal Regulation ◽  
Adrenocorticotropic Hormone ◽  
Vibration Exposure ◽  
Noise And Vibration ◽  
Experimental Animals ◽  
In Blood Plasma

When exposed to noise and vibration in experimental animals there was a decrease in the content of threeiodinethyronine, thyroxin and adrenocorticotropic hormone in blood plasma after 15 and 30 days of experience. An increase in loads led to an increase in the level of threeiodinethyronine and thyroxin under vibration exposure and was normalized with noise. The content of adrenocorticotropic hormone leveled in both cases.

scholarly journals Calcium-Sensing Receptor Stimulation in Cultured Glomerular Podocytes Induces TRPC6-Dependent Calcium Entry and RhoA Activation

2017 ◽  
Vol 43 (5) ◽  
pp. 1777-1789 ◽  
Author(s):  
Lei Zhang ◽  
Tianrong Ji ◽  
Qin Wang ◽  
Kexin Meng ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Protective Action ◽  
Focal Adhesions ◽  
Stress Fiber ◽  
Fiber Formation ◽  
Stress Fibers ◽  
Dependent Manner ◽  
Calcium Sensing Receptor ◽  
Rhoa Activity ◽  
Rhoa Activation ◽  
Calcium Sensing

Background/Aims: Recent studies provided compelling evidence that stimulation of the calcium sensing receptor (CaSR) exerts direct renoprotective action at the glomerular podocyte level. This protective action may be attributed to the RhoA-dependent stabilization of the actin cytoskeleton. However, the underlying mechanisms remain unclear. Methods: In the present study, an immortalized human podocyte cell line was used. Fluo-3 fluorescence was utilized to determine intracellular Ca2+ concentration ([Ca2+]i), and western blotting was used to measure canonical transient receptor potential 6 (TRPC6) protein expression and RhoA activity. Stress fibers were detected by FITC-phalloidin. Results: Activating CaSR with a high extracellular Ca2+ concentration ([Ca2+]o) or R-568 (a type II CaSR agonist) induces an increase in the [Ca2+]i in a dose-dependent manner. This increase in [Ca2+]i is phospholipase C (PLC)-dependent and is smaller in the absence of extracellular Ca2+ than in the presence of 0.5 mM [Ca2+]o. The CaSR activation-induced [Ca2+]i increase is attenuated by the pharmacological blockage of TRPC6 channels or siRNA targeting TRPC6. These data suggest that TRPC6 is involved in CaSR activation-induced Ca2+ influx. Consistent with a previous study, CaSR stimulation results in an increase in RhoA activity. However, the knockdown of TRPC6 significantly abolished the RhoA activity increase induced by CaSR stimulation, suggesting that TRPC6-dependent Ca2+ entry is required for RhoA activation. The activated RhoA is involved in the formation of stress fibers and focal adhesions in response to CaSR stimulation because siRNA targeting RhoA attenuated the increase in the stress fiber mediated by CaSR stimulation. Moreover, this effect of CaSR activation on the formation of stress fibers is also abolished by the knockdown of TRPC6. Conclusion: TRPC6 is involved in the regulation of stress fiber formation and focal adhesions via the RhoA pathway in response to CaSR activation. This may explain the direct protective action of CaSR agonists.

Platelet-derived growth factor induces rapid and sustained tyrosine phosphorylation of phospholipase C-gamma in quiescent BALB/c 3T3 cells

1989 ◽  
Vol 9 (7) ◽  
pp. 2934-2943
Author(s):  
M I Wahl ◽  
N E Olashaw ◽  
S Nishibe ◽  
S G Rhee ◽  
W J Pledger ◽  
...  
Keyword(s):  
Growth Factor ◽  
Phospholipase C ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Hormonal Regulation ◽  
Growth Factor Receptor ◽  
Fold Increase ◽  
Platelet Derived Growth Factor ◽  
3T3 Cells ◽  
Pdgf Stimulation

Platelet-derived growth factor (PDGF) stimulates the proliferation of quiescent fibroblasts through a series of events initiated by activation of tyrosine kinase activity of the PDGF receptor at the cell surface. Physiologically significant substrates for this or other growth factor receptor or oncogene tyrosine kinases have been difficult to identify. Phospholipase C (PLC), a key enzyme of the phosphoinositide pathway, is believed to be an important site for hormonal regulation of the hydrolysis of phosphatidylinositol 4,5-bisphosphate, which produces the intracellular second-messenger molecules inositol 1,4,5-trisphosphate and 1,2-diacylglycerol. Treatment of BALB/c 3T3 cells with PDGF led to a rapid (within 1 min) and significant (greater than 50-fold) increase in PLC activity, as detected in eluates of proteins from a phosphotyrosine immunoaffinity matrix. This PDGF-stimulated increase in phosphotyrosine-immunopurified PLC activity occurred for up to 12 h after addition of growth factor to quiescent cells. Interestingly, the PDGF stimulation occurred at 3 as well as 37 degrees C and in the absence or presence of extracellular Ca2+. Immunoprecipitation of cellular proteins with monoclonal antibodies specific for three distinct cytosolic PLC isozymes demonstrated the presence of a 145-kilodalton isozyme, PLC-gamma (formerly PLC-II), in BALB/c 3T3 cells. Furthermore, these immunoprecipitation studies showed that PLC-gamma is rapidly phosphorylated on tyrosine residues after PDGF stimulation. The results suggest that mitogenic signaling by PDGF is coincident with tyrosine phosphorylation of PLC-gamma.

Evidence that tyrosine phosphorylation may increase tight junction permeability

1995 ◽  
Vol 108 (2) ◽  
pp. 609-619 ◽  
Author(s):  
J.M. Staddon ◽  
K. Herrenknecht ◽  
C. Smales ◽  
L.L. Rubin
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Tyrosine Phosphorylation ◽  
Mdck Cells ◽  
Tyrosine Phosphatase ◽  
Adherens Junction ◽  
Brain Endothelial Cells ◽  
Phenylarsine Oxide ◽  
Phosphatase Inhibitor ◽  
Tight Junction Permeability

Tight junction permeability control is important in a variety of physiological and pathological processes. We have investigated the role of tyrosine phosphorylation in the regulation of tight junction permeability. MDCK epithelial cells and brain endothelial cells were grown on filters and tight junction permeability was determined by transcellular electrical resistance (TER). The tyrosine phosphatase inhibitor pervanadate caused a concentration- and time-dependent decrease in TER in both MDCK and brain endothelial cells. However, as expected, pervanadate resulted in the tyrosine phosphorylation of many proteins; hence interpretation of its effects are extremely difficult. Phenylarsine oxide, a more selective tyrosine phosphatase inhibitor, caused the tyrosine phosphorylation of relatively few proteins as analyzed by immunoblotting of whole cell lysates. This inhibitor, like pervanadate, also elicited a decrease in TER in the two cell types. In the MDCK cells, the action of phenylarsine oxide could be reversed by the subsequent addition of the reducing agent 2,3-dimercaptopropanol. Immunocytochemistry revealed that phenylarsine oxide rapidly stimulated the tyrosine phosphorylation of proteins associated with intercellular junctions. Because of the known influence of the adherens junction on tight junctions, we analyzed immunoprecipitates of the E-cadherin/catenin complex from MDCK cells treated with phenylarsine oxide. This revealed an increase in the tyrosine phosphorylation of beta-catenin, but not of alpha-catenin. However, the tight junction associated protein ZO-1 was also tyrosine phosphorylated after PAO treatment. These data indicate that tight junction permeability may be regulated via mechanisms involving tyrosine phosphorylation of adherens junction and tight junction proteins.

Autonomous expression of a noncatalytic domain of the focal adhesion-associated protein tyrosine kinase pp125FAK

1993 ◽  
Vol 13 (2) ◽  
pp. 785-791
Author(s):  
M D Schaller ◽  
C A Borgman ◽  
J T Parsons
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Protein Tyrosine Kinase ◽  
Signal Transduction Pathway ◽  
Focal Adhesions ◽  
Cellular Adhesion ◽  
Protein Tyrosine ◽  
Intracellular Signals ◽  
Embryo Cells

Integrins play a central role in cellular adhesion and anchorage of the cytoskeleton and participate in the generation of intracellular signals, including tyrosine phosphorylation. We have recently isolated a cDNA encoding a unique, focal adhesion-associated protein tyrosine kinase (FAK) that is a component of an integrin-mediated signal transduction pathway. Here we report the isolation of cDNAs encoding the C-terminal, noncatalytic domain of the FAK kinase, termed FRNK (FAK-related nonkinase). Both the FAK- and FRNK-encoded polypeptides, pp125FAK and p41/p43FRNK, are expressed in normal chicken embryo cells. pp125FAK and p41/p43FRNK were localized to focal adhesions, suggesting that pp125FAK is directed to the focal adhesions by sequences within its C-terminal domain. We also show that the fibronectin-dependent increase in tyrosine phosphorylation of pp125FAK is accompanied by a concomitant posttranslational modification of p41FRNK.

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