Osmotic shrinkage elicits FAK- and Src phosphorylation and Src-dependent NKCC1 activation in NIH3T3 cells

2015 ◽  
Vol 308 (2) ◽  
pp. C101-C110 ◽  
Author(s):  
Line Jee Hartmann Rasmussen ◽  
Helene Steenkær Holm Müller ◽  
Bente Jørgensen ◽  
Stine Falsig Pedersen ◽  
Else Kay Hoffmann
Keyword(s):  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Volume Regulation ◽  
Mammalian Cells ◽  
Myosin Light Chain ◽  
Janus Kinase ◽  
Nih3t3 Cells ◽  
Src Inhibitor ◽  
Nonreceptor Tyrosine Kinases

The mechanisms linking cell volume sensing to volume regulation in mammalian cells remain incompletely understood. Here, we test the hypothesis that activation of nonreceptor tyrosine kinases Src, focal adhesion kinase (FAK), and Janus kinase-2 (Jak2) occurs after osmotic shrinkage of NIH3T3 fibroblasts and contributes to volume regulation by activation of NKCC1. FAK phosphorylation at Tyr397, Tyr576/577, and Tyr861 was increased rapidly after exposure to hypertonic (575 mOsm) saline, peaking after 10 (Tyr397, Tyr576/577) and 10–30 min (Tyr861). Shrinkage-induced Src family kinase autophosphorylation (pTyr416-Src) was induced after 2–10 min, and immunoprecipitation indicated that this reflected phosphorylation of Src itself, rather than Fyn and Yes. Phosphorylated Src and FAK partly colocalized with vinculin, a focal adhesion marker, after hypertonic shrinkage. The Src inhibitor pyrazolopyrimidine-2 (PP2, 10 μM) essentially abolished shrinkage-induced FAK phosphorylation at Tyr576/577 and Tyr861, yet not at Tyr397, and inhibited shrinkage-induced NKCC1 activity by ∼50%. The FAK inhibitor PF-573,228 augmented shrinkage-induced Src phosphorylation, and inhibited shrinkage-induced NKCC1 activity by ∼15%. The apparent role of Src in NKCC1 activation did not reflect phosphorylation of myosin light chain kinase (MLC), which was unaffected by shrinkage and by PP2, but may involve Jak2, a known target of Src, which was rapidly activated by osmotic shrinkage and inhibited by PP2. Collectively, our findings suggest a major role for Src and possibly the Jak2 axis in shrinkage-activation of NKCC1 in NIH3T3 cells, whereas no evidence was found for major roles for FAK and MLC in this process.

Physiological significance of volume-regulatory transporters

1999 ◽  
Vol 276 (5) ◽  
pp. C995-C1011 ◽  
Author(s):  
W. Charles O’Neill
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Mammalian Cells ◽  
Ion Transporters ◽  
Subsequent Growth ◽  
The Past ◽  
Shrinkage And Swelling ◽  
Acute Changes

Research over the past 25 years has identified specific ion transporters and channels that are activated by acute changes in cell volume and that serve to restore steady-state volume. The mechanism by which cells sense changes in cell volume and activate the appropriate transporters remains a mystery, but recent studies are providing important clues. A curious aspect of volume regulation in mammalian cells is that it is often absent or incomplete in anisosmotic media, whereas complete volume regulation is observed with isosmotic shrinkage and swelling. The basis for this may lie in an important role of intracellular Cl− in controlling volume-regulatory transporters. This is physiologically relevant, since the principal threat to cell volume in vivo is not changes in extracellular osmolarity but rather changes in the cellular content of osmotically active molecules. Volume-regulatory transporters are also closely linked to cell growth and metabolism, producing requisite changes in cell volume that may also signal subsequent growth and metabolic events. Thus, despite the relatively constant osmolarity in mammals, volume-regulatory transporters have important roles in mammalian physiology.

scholarly journals The Thrombopoietin Receptor Can Mediate Proliferation without Activation of the Jak-STAT Pathway

1997 ◽  
Vol 186 (12) ◽  
pp. 1947-1955 ◽  
Author(s):  
Marion Dorsch ◽  
Pang-Dian Fan ◽  
Nika N. Danial ◽  
Paul B. Rothman ◽  
Stephen P. Goff
Keyword(s):  
Tyrosine Kinases ◽  
Kinase Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Signal Transducers ◽  
Thrombopoietin Receptor ◽  
Mitogen Activated Protein ◽  
Mutant Receptors ◽  
Nonreceptor Tyrosine Kinases ◽  
Stat Pathway

Cytokine receptors of the hematopoietic receptor superfamily lack intrinsic tyrosine kinase domains for the intracellular transmission of their signals. Instead all members of this family associate with Jak family nonreceptor tyrosine kinases. Upon ligand stimulation of the receptors, Jaks are activated to phosphorylate target substrates. These include STAT (signal transducers and activators of transcription) proteins, which after phosphorylation translocate to the nucleus and modulate gene expression. The exact role of the Jak-STAT pathway in conveying growth and differentiation signals remains unclear. Here we describe a deletion mutant of the thrombopoietin receptor (c-mpl) that has completely lost the capacity to activate Jaks and STATs but retains its ability to induce proliferation. This mutant still mediates TPO-induced phosphorylation of Shc, Vav, mitogen-activated protein kinase (MAPK) and Raf-1 as well as induction of c-fos and c-myc, although at somewhat reduced levels. Furthermore, we show that both wild-type and mutant receptors activate phosphatidylinositol (PI) 3-kinase upon thrombopoietin stimulation and that thrombopoietin-induced proliferation is inhibited in the presence of the PI 3-kinase inhibitor wortmannin. These results demonstrate that the Jak-STAT pathway is dispensable for the generation of mitogenic signals by a cytokine receptor.

scholarly journals Mutation in the Jak kinase JH2 domain hyperactivates Drosophila and mammalian Jak-Stat pathways.

1997 ◽  
Vol 17 (3) ◽  
pp. 1562-1571 ◽  
Author(s):  
H Luo ◽  
P Rose ◽  
D Barber ◽  
W P Hanratty ◽  
S Lee ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Critical Role ◽  
Developmental Defects ◽  
Type D ◽  
Jak Kinase ◽  
Lysine Substitution ◽  
Nonreceptor Tyrosine Kinases ◽  
Drosophila Cells ◽  
Stat Pathway

The Jak (Janus) family of nonreceptor tyrosine kinases plays a critical role in cytokine signal transduction pathways. In Drosophila melanogaster, the dominant hop(Tum-l) mutation in the Hop Jak kinase causes leukemia-like and other developmental defects. Previous studies have suggested that the Hop(Tum-l) protein might be a hyperactive kinase. Here, we report on the new dominant mutation hop(T42), which causes abnormalities that are similar to but more extreme than those caused by hop(Tum-l). We determined that Hop(T42) contains a glutamic acid-to-lysine substitution at amino acid residue 695 (E695K). This residue occurs in the JH2 (kinase-like) domain and is conserved among all Jak family members. We determined that Hop(Tum-1) and Hop(T42) both hyperphosphorylated and hyperactivated D-Stat when overexpressed in Drosophila cells. Moreover, we found that the hop(T42) phenotype was partially rescued by a reduction of wild-type D-stat activity. Finally, generation of the corresponding E695K mutation in murine Jak2 resulted in increased autophosphorylation and increased activation of Stat5 in COS cells. These results demonstrate that the mutant Hop proteins do indeed have increased tyrosine kinase activity, that the mutations hyperactivate the Hop-D-Stat pathway, and that Drosophila is a relevant system for the functional dissection of mammalian Jak-Stat pathways. Finally, we propose a model for the role of the Hop-D-Stat pathway in Drosophila hematopoiesis.

scholarly journals Entry of Neisseria meningitidis into Mammalian Cells Requires the Src Family Protein Tyrosine Kinases

2010 ◽  
Vol 78 (5) ◽  
pp. 1905-1914 ◽  
Author(s):  
Heiko Slanina ◽  
Alexandra König ◽  
Sabrina Hebling ◽  
Christof R. Hauck ◽  
Matthias Frosch ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Neisseria Meningitidis ◽  
Tyrosine Kinases ◽  
Mammalian Cells ◽  
Kinase Inhibitor ◽  
Cell Types ◽  
Protein Tyrosine Kinases ◽  
Protein Tyrosine ◽  
Src Inhibitor ◽  
Intracellular Signals

ABSTRACT Neisseria meningitidis, the causative agent of meningitis and septicemia, is able to attach to and invade a variety of cell types. In a previous study we showed that entry of N. meningitidis into human brain microvascular endothelial cells (HBMEC) is mediated by fibronectin bound to the outer membrane protein Opc, which forms a molecular bridge to α5β1-integrins. This interaction results in cytoskeletal remodeling and uptake of the bacteria. In this study we identified and characterized the intracellular signals involved in integrin-initiated uptake of N. meningitidis. We determined that the Src protein tyrosine kinases (PTKs) are activated in response to contact with N. meningitidis. Inhibition of Src PTK activity by the general tyrosine kinase inhibitor genistein and the specific Src inhibitor PP2 reduced Opc-mediated invasion of HBMEC and human embryonic kidney (HEK) 293T cells up to 90%. Moreover, overexpression of the cellular Src antagonist C-terminal Src kinase (CSK) also significantly reduced N. meningitidis invasion. Src PTK-deficient fibroblasts were impaired in the ability to internalize N. meningitidis and showed reduced phosphorylation of the cytoskeleton and decreased development of stress fibers. These data indicate that the Src family PTKs, particularly the Src protein, along with other proteins, are important signal proteins that are responsible for the transfer of signals from activated integrins to the cytoskeleton and thus mediate the endocytosis of N. meningitidis into brain endothelial cells.

scholarly journals Platelet-derived growth factor (PDGF)-induced activation of signal transducer and activator of transcription (Stat) 5 is mediated by PDGF β-receptor and is not dependent on c-Src, Fyn, Jak1 or Jak2 kinases

2000 ◽  
Vol 345 (3) ◽  
pp. 759-766 ◽  
Author(s):  
Kirsi PAUKKU ◽  
Sigrídur VALGEIRSDÓTTIR ◽  
Pipsa SAHARINEN ◽  
Mathias BERGMAN ◽  
Carl-Henrik HELDIN ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinases ◽  
Mammalian Cells ◽  
Platelet Derived Growth Factor ◽  
Wild Type ◽  
Signal Transducers ◽  
Tyrosine Residues ◽  
Type C ◽  
Β Receptor

Several growth factors activate signal transducers and activators of transcription (Stats) but the mechanism of Stat activation in receptor tyrosine kinase signalling has remained elusive. In the present study we have analysed the roles of different platelet-derived growth factor (PDGF)-induced tyrosine kinases in the activation of Stat5. Co-expression experiments in insect and mammalian cells demonstrated that both PDGF β-receptor (PDGF β-R) and Jak1, but not c-Src, induced the activation of Stat5. Furthermore, immune-complex-purified PDGF β-R was able to phosphorylate Stat5 directly. The role of the cytoplasmic tyrosine kinases in the PDGF-induced activation of Stat5 was further investigated by overexpressing kinase-negative (KN) and wild-type Jak and c-Src kinases. Jak1-KN or Jak2-KN had no effect but both Src-KN and wild-type c-Src similarly decreased the PDGF-β-R-induced activation of Stat5. The activation of both Src and Stat5 is dependent on the same tyrosine residues Tyr579 and Tyr581 in PDGF β-R; thus the observed inhibition by Src might result from competition for binding of Stat5 to the receptor. Finally, fibroblasts derived from Src-/- and Fyn-/- mice showed normal pattern of PDGF-induced tyrosine phosphorylation of Stat5. Taken together, these results indicate that Stat5 is a direct substrate for PDGF β-R and that the activation does not require Jak1, Jak2, c-Src or Fyn tyrosine kinases.

scholarly journals Kindlin-2 promotes rear focal adhesion disassembly and directional persistence in cell migration

2020 ◽  
pp. jcs.244616
Author(s):  
Jie Liu ◽  
Zhongzhen Liu ◽  
Keng Chen ◽  
Wei Chen ◽  
Xiyuan Fang ◽  
...  
Keyword(s):  
Cell Migration ◽  
Focal Adhesion ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Molecular Level ◽  
Trailing Edge ◽  
Serum Stimulation ◽  
Actomyosin Contractility

Cell migration involves front-rear asymmetric FA dynamics, which facilitates trailing edge detachment and directional persistence. Here we show that kinldin-2 is critical for FA sliding and disassembly in migrating cells. Loss of kindlin-2 markedly reduced FA number and selectively impaired rear FA sliding and disassembly, resulting in defective rear retraction and reduced directional persistence during cell migration. Kindlin-2 deficient cells failed to develop serum-induced actomyosin-dependent tension at FAs. At the molecular level, kindlin-2 directly interacted with myosin light chain kinase (MLCK), which was enhanced in response to serum stimulation. Serum deprivation inhibited rear FA disassembly, which was released in response to serum stimulation. Overexpression of the MLCK-binding kindlin-2 F0F1 fragment (aa 1-167), which inhibits the interaction of endogenous kindlin-2 with MLCK, phenocopied kindlin-2 deficiency-induced migration defects. Inhibition of MLCK, like loss of kindlin-2, also impaired trailing edge detachment, rear FA disassembly and directional persistence. These results suggest a role of kindlin-2 in promoting actomyosin contractility at FAs, leading to increased rear FA sliding and disassembly and directional persistence in cell migration.

scholarly journals Crystal structure of the Jak3 kinase domain in complex with a staurosporine analog

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 996-1002 ◽  
Author(s):  
Titus J. Boggon ◽  
Yiqun Li ◽  
Paul W. Manley ◽  
Michael J. Eck
Keyword(s):  
Crystal Structure ◽  
Tyrosine Kinases ◽  
Severe Combined Immunodeficiency ◽  
Kinase Domain ◽  
Janus Kinase ◽  
Cytokine Signaling ◽  
Activation Loop ◽  
Gamma Chain ◽  
The Common ◽  
Nonreceptor Tyrosine Kinases

AbstractJak (Janus kinase) family nonreceptor tyrosine kinases are central mediators of cytokine signaling. The Jak kinases exhibit distinct cytokine receptor association profiles and so transduce different signals. Jak3 expression is limited to the immune system, where it plays a key role in signal transduction from cytokine receptors containing the common gamma-chain, γc. Patients unable to signal via γc present with severe combined immunodeficiency (SCID). The finding that Jak3 mutations result in SCID has made it a target for development of lymphocyte-specific immunosuppressants. Here, we present the crystal structure of the Jak3 kinase domain in complex with staurosporine analog AFN941. The kinase domain is in the active conformation, with both activation loop tyrosine residues phosphorylated. The phosphate group on pTyr981 in the activation loop is in part coordinated by an arginine residue in the regulatory C-helix, suggesting a direct mechanism by which the active position of the C-helix is induced by phosphorylation of the activation loop. Such a direct coupling has not been previously observed in tyrosine kinases and may be unique to Jak kinases. The crystal structure provides a detailed view of the Jak3 active site and will facilitate computational and structure-directed approaches to development of Jak3-specific inhibitors.

scholarly journals Role of Focal Adhesion Tyrosine Kinases in GPVI-Dependent Platelet Activation and Reactive Oxygen Species Formation

PLoS ONE ◽  
2014 ◽  
Vol 9 (11) ◽  
pp. e113679 ◽  
Author(s):  
Naadiya Carrim ◽  
Tony G. Walsh ◽  
Alessandra Consonni ◽  
Mauro Torti ◽  
Michael C. Berndt ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Platelet Activation ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Reactive Oxygen Species Formation ◽  
Species Formation

scholarly journals Focal Adhesion Kinases in Adhesion Structures and Disease

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Pierre P. Eleniste ◽  
Angela Bruzzaniti
Keyword(s):  
Focal Adhesion ◽  
Structural Design ◽  
Tyrosine Kinases ◽  
Essential Role ◽  
Focal Adhesions ◽  
Basic Function ◽  
Contact Structures ◽  
Wide Range ◽  
Compare And Contrast

Cell adhesion to the extracellular matrix (ECM) is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organization and role of focal adhesions, podosomes, and invadopodia in different cells. In addition, we discuss the role of the tyrosine kinases, FAK, Pyk2, and Src, which are critical for the function of the different adhesion structures. Finally, we discuss the essential role of these tyrosine kinases from the perspective of human diseases.

scholarly journals Regulation of Fibroblast Cell Polarity by Src Tyrosine Kinase

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 135
Author(s):  
Kazuo Katoh
Keyword(s):  
Cell Polarity ◽  
Cell Elongation ◽  
Tyrosine Kinases ◽  
Focal Adhesions ◽  
Fibroblast Cell ◽  
Dominant Negative ◽  
Src Tyrosine Kinase ◽  
Src Inhibitor ◽  
Src Gene ◽  
Nonreceptor Tyrosine Kinases

Src protein tyrosine kinases (SFKs) are a family of nonreceptor tyrosine kinases that are localized beneath the plasma membrane and are activated during cell adhesion, migration, and elongation. Due to their involvement in the activation of signal transduction cascades, SFKs have been suggested to play important roles in the determination of cell polarity during cell extension and elongation. However, the mechanism underlying Src-mediated polarity formation remains unclear. The present study was performed to investigate the mechanisms underlying Src-induced cell polarity formation and cell elongation using Src knockout fibroblasts (SYFs) together with an inhibitor of Src. Normal and Src knockout fibroblasts were also transfected with a wild-type c-Src, dominant negative c-Src, or constitutively active c-Src gene to analyze the changes in cell morphology. SYF cells cultured on a glass substrate elongated symmetrically into spindle-shaped cells, with the formation of focal adhesions at both ends of the cells. When normal fibroblasts were treated with Src Inhibitor No. 5, a selective inhibitor of Src tyrosine kinases, they elongated into symmetrical spindle-shaped cells, similar to SYF cells. These results suggest that cell polarity during extension and elongation may be regulated by SFKs and that the expression and regulation of Src are important for the formation of polarity during cell elongation.

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