scholarly journals Integrin-dependent phosphorylation and activation of the protein tyrosine kinase pp125FAK in platelets.

1992 ◽  
Vol 119 (4) ◽  
pp. 905-912 ◽  
Author(s):  
L Lipfert ◽  
B Haimovich ◽  
M D Schaller ◽  
B S Cobb ◽  
J T Parsons ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Immune Complex ◽  
Strong Correlation ◽  
Actin Polymerization ◽  
Protein Tyrosine Kinase ◽  
Focal Adhesions ◽  
Protein Tyrosine ◽  
Fibrinogen Binding

We have investigated mechanisms involved in integrin-mediated signal transduction in platelets by examining integrin-dependent phosphorylation and activation of a newly identified protein tyrosine kinase, pp125FAK (FAK, focal adhesion kinase). This kinase was previously shown to be localized in focal adhesions in fibroblasts, and to be phosphorylated on tyrosine in normal and Src-transformed fibroblasts. We show that thrombin and collagen activation of platelets causes an induction of tyrosine phosphorylation of pp125FAK and that pp125FAK molecules isolated from activated platelets display enhanced levels of phosphorylation in immune-complex kinase assays. pp125FAK was not phosphorylated on tyrosine after thrombin or collagen treatment of Glanzmann's thrombasthenic platelets deficient in the fibrinogen receptor GPIIb-IIIa, or of platelets pretreated with an inhibitory monoclonal antibody to GP IIb-IIIa. Fibrinogen binding to GP IIb-IIIa was not sufficient to induce pp125FAK phosphorylation because pp125FAK was not phosphorylated on tyrosine in thrombin-treated platelets that were not allowed to aggregate. These results indicate that tyrosine phosphorylation of pp125FAK is dependent on platelet aggregation mediated by fibrinogen binding to the integrin receptor GP IIb-IIIa. The induction of tyrosine phosphorylation of pp125FAK was inhibited in thrombin- and collagen-treated platelets preincubated with cytochalasin D, which prevents actin polymerization following activation. Under all of these conditions, there was a strong correlation between the induction of tyrosine phosphorylation of pp125FAK in vivo and stimulation of the phosphorylation of pp125FAK in vitro in immune-complex kinase assays. This study provides the first genetic evidence that tyrosine phosphorylation of pp125FAK is dependent on integrin-mediated events, and demonstrates that there is a strong correlation between tyrosine phosphorylation of pp125FAK in platelets, and the activation of pp125FAK-associated phosphorylating activity in vitro.

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.

scholarly journals SRC family kinases in hamster spermatozoa: evidence for the presence of LCK

Reproduction ◽  
2017 ◽  
Vol 153 (5) ◽  
pp. 655-669 ◽  
Author(s):  
Durgesh Kumar Singh ◽  
Rohit Kumar Deshmukh ◽  
Praveen Kumar Narayanan ◽  
Sisinthy Shivaji ◽  
Archana Bharadwaj Siva
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Kinase ◽  
Specific Inhibitor ◽  
Specific Protein ◽  
Src Family Kinases ◽  
Sperm Capacitation ◽  
Protein Tyrosine

Sperm capacitation is a prerequisite for successful fertilization. Increase in tyrosine phosphorylation is considered the hallmark of capacitation and attempts to understand its regulation are ongoing. In this regard, we attempted to study the role of SRC family kinases (SFKs) in the hamster sperm functions. Interestingly, we found the presence of the lymphocyte-specific protein tyrosine kinase, LCK, in mammalian spermatozoa and further characterized it in terms of its localization and function. LCK was found in spermatozoa of several species, and its transcript was identified in the hamster testis. Autophosphorylation of LCK at the Y394 residue increased as capacitation progressed, indicating an upregulation of LCK activity during capacitation. Inhibition of LCK (and perhaps the other SFKs) with the use of a specific inhibitor showed a significant decrease in protein tyrosine phosphorylation of several proteins, implying LCK/SFKs as key tyrosine kinase(s) regulating tyrosine phosphorylation during hamster sperm capacitation. Dihydrolipoamide dehydrogenase was identified as a substrate for LCK/SFK. LCK/SFKs inhibition significantly reduced the percentage fertilization (in vitro) but had no effect on sperm motility, hyperactivation and acrosome reaction. In summary, this is the first report on the presence of LCK, an SFK of hematopoietic lineage in spermatozoa besides being the first study on the role of SFKs in the spermatozoa of Syrian hamsters.

Erythropoietin induces association of the JAK2 protein tyrosine kinase with the erythropoietin receptor in vivo

Blood ◽  
1994 ◽  
Vol 84 (5) ◽  
pp. 1501-1507 ◽  
Author(s):  
O Miura ◽  
N Nakamura ◽  
FW Quelle ◽  
BA Witthuhn ◽  
JN Ihle ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Immune Complex ◽  
Proximal Region ◽  
Erythropoietin Receptor ◽  
Tyrosine Kinase Domain ◽  
Protein Tyrosine ◽  
Cytoplasmic Region

Abstract Protein tyrosine phosphorylation has been hypothesized to play a key role in the growth signaling induced by erythropoietin (Epo), although the Epo receptor (EpoR), a member of the cytokine receptor superfamily, lacks a tyrosine kinase domain. Recently, the JAK2 tyrosine kinase was shown to be activated on Epo stimulation and to bind to the cytoplasmic domain of EpoR in vitro. To further explore the mechanisms of activation of JAK2 in EpoR-mediated signal transduction, we assessed the conditions for association of JAK2 with EpoR in vivo. Epo stimulation rapidly induced association of JAK2 with the EpoR in an interleukin 3 (IL-3)-dependent cell line transfected with the wild-type EpoR. On Epo stimulation JAK2 also associated with a truncated mutant EpoR (H-mutant), which is mitogenetically active but not tyrosine phosphorylated, indicating that association does not require receptor phosphorylation and occurs in the membrane proximal region. However, association was not detected with mutant receptors inactivated by an internal deletion or a point mutation, Trp282 to Arg, in a membrane- proximal cytoplasmic region (PB or PM4 mutant, respectively). Immune complex kinase assays of anti-EpoR immunoprecipitates also revealed that activated JAK2 associates with the EpoR in Epo-stimulated cells. By this approach, association also occurred with the mitogenically active H mutant but not with the mitogenically inactive PB or PM4 mutants. In the immune complex kinases assays, EpoR, JAK2, and a 150-kD protein were phosphorylated on tyrosine. Taken together, the results further support the hypothesis that, on Epo stimulation, JAK2 associates with the membrane-proximal cytoplasmic region of the EpoR to be activated and induces tyrosine phosphorylation of cellular substrates, including the EpoR, to transduce a growth signal.

scholarly journals 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.

scholarly journals Erythropoietin induces association of the JAK2 protein tyrosine kinase with the erythropoietin receptor in vivo

Blood ◽  
1994 ◽  
Vol 84 (5) ◽  
pp. 1501-1507 ◽  
Author(s):  
O Miura ◽  
N Nakamura ◽  
FW Quelle ◽  
BA Witthuhn ◽  
JN Ihle ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Immune Complex ◽  
Proximal Region ◽  
Erythropoietin Receptor ◽  
Tyrosine Kinase Domain ◽  
Protein Tyrosine ◽  
Cytoplasmic Region

Protein tyrosine phosphorylation has been hypothesized to play a key role in the growth signaling induced by erythropoietin (Epo), although the Epo receptor (EpoR), a member of the cytokine receptor superfamily, lacks a tyrosine kinase domain. Recently, the JAK2 tyrosine kinase was shown to be activated on Epo stimulation and to bind to the cytoplasmic domain of EpoR in vitro. To further explore the mechanisms of activation of JAK2 in EpoR-mediated signal transduction, we assessed the conditions for association of JAK2 with EpoR in vivo. Epo stimulation rapidly induced association of JAK2 with the EpoR in an interleukin 3 (IL-3)-dependent cell line transfected with the wild-type EpoR. On Epo stimulation JAK2 also associated with a truncated mutant EpoR (H-mutant), which is mitogenetically active but not tyrosine phosphorylated, indicating that association does not require receptor phosphorylation and occurs in the membrane proximal region. However, association was not detected with mutant receptors inactivated by an internal deletion or a point mutation, Trp282 to Arg, in a membrane- proximal cytoplasmic region (PB or PM4 mutant, respectively). Immune complex kinase assays of anti-EpoR immunoprecipitates also revealed that activated JAK2 associates with the EpoR in Epo-stimulated cells. By this approach, association also occurred with the mitogenically active H mutant but not with the mitogenically inactive PB or PM4 mutants. In the immune complex kinases assays, EpoR, JAK2, and a 150-kD protein were phosphorylated on tyrosine. Taken together, the results further support the hypothesis that, on Epo stimulation, JAK2 associates with the membrane-proximal cytoplasmic region of the EpoR to be activated and induces tyrosine phosphorylation of cellular substrates, including the EpoR, to transduce a growth signal.

Protein-tyrosine Kinase p72 syk Is Activated by Platelet Activating Factor in Platelets

1994 ◽  
Vol 72 (06) ◽  
pp. 937-941 ◽  
Author(s):  
Karim Rezaul ◽  
Shigeru Yanagi ◽  
Kiyonao Sada ◽  
Takanobu Taniguchi ◽  
Hirohei Yamamura
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Critical Role ◽  
Platelet Activating Factor ◽  
Kinase Assay ◽  
Potential Candidate ◽  
Protein Tyrosine ◽  
Induced Aggregation

SummaryIt has been demonstrated that activation of platelets by platelet-activating factor (PAF) results in a dramatic increase in tyrosine phosphorylation of several cellular proteins. We report here that p72 syk is a potential candidate for the protein-tyrosine phosphorylation following PAF stimulation in porcine platelets. Immunoprecipitation kinase assay revealed that PAF stimulation resulted in a rapid activation of p72 syk which peaked at 10 s. The level of activation was found to be dose dependent and could be completely inhibited by the PAF receptor antagonist, CV3988. Phosphorylation at the tyrosine residues of p72 syk coincided with activation of yllsyk. Pretreatment of platelets with aspirin and apyrase did not affect PAF induced activation of p72 syk .Furthermore, genistein, a potent protein-tyrosine-kinase inhibitor, diminished PAF-induced p72 syk activation and Ca2+ mobilization as well as platelet aggregation. These results suggest that p72 syk may play a critical role in PAF-induced aggregation, possibly through regulation of Ca2+ mobilization.

Activation of c-Src in cells bearing v-Crk and its suppression by Csk

1992 ◽  
Vol 12 (10) ◽  
pp. 4706-4713
Author(s):  
H Sabe ◽  
M Okada ◽  
H Nakagawa ◽  
H Hanafusa
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Src Kinase ◽  
Cellular Protein ◽  
Morphological Transformation ◽  
Protein Tyrosine ◽  
In Cells

The protein product of the CT10 virus, p47gag-crk (v-Crk), which contains Src homology region 2 (SH2) and 3 (SH3) domains but lacks a kinase domain, is believed to cause an increase in cellular protein tyrosine phosphorylation. A candidate tyrosine kinase, Csk (C-terminal Src kinase), has been implicated in c-Src Tyr-527 phosphorylation, which negatively regulates the protein tyrosine kinase of pp60c-src (c-Src). To investigate how c-Src kinase activity is regulated in vivo, we first looked at whether v-Crk can activate c-Src kinase. We found that cooverexpression of v-Crk and c-Src caused elevation of c-Src kinase activity, resulting in an increase of tyrosine phosphorylation of cellular proteins and morphological transformation of rat 3Y1 fibroblasts. v-Crk and c-Src complexes were not detected, although v-Crk bound to a variety of tyrosine-phosphorylated proteins in cells overexpressing v-Crk and c-Src. Overexpression of Csk in these transformed cells caused reversion to normal phenotypes and also reduced the level of c-Src kinase activity. However, Csk did not cause reversion of cells transformed by v-Src or c-Src527F, in which Tyr-527 was changed to Phe. These results strongly suggest that Csk acts on Tyr-527 of c-Src and suppresses c-Src kinase activity in vivo. Because Csk can suppress transformation by cooverexpression of v-Crk and c-Src, we suggest that v-Crk causes activation of c-Src in vivo by altering the phosphorylation state of Tyr-527.

The GPI-anchored adhesion molecule F3 induces tyrosine phosphorylation: involvement of the FNIII repeats

1996 ◽  
Vol 109 (3) ◽  
pp. 699-704 ◽  
Author(s):  
M. Cervello ◽  
V. Matranga ◽  
P. Durbec ◽  
G. Rougon ◽  
S. Gomez
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Cho Cells ◽  
Intracellular Signaling ◽  
Protein Tyrosine Kinase ◽  
Cross Linking ◽  
Protein Tyrosine ◽  
Intracellular Signaling Pathway ◽  
Type Iii ◽  
Cell Cell

The glycosyl-phosphatidylinositol (GPI)-anchored F3 molecule, a member of the Ig superfamily made up of Ig and FNIII-like domains, is involved in cell-cell adhesion, neuronal pathfinding and fasciculation. Little is known about the mechanism(s) that governs the F3-mediated cell-cell recognition. In particular, it is not known whether F3 transduces signals across the membrane. Here we show that in F3-transfected CHO cells (1A cells) an increase in tyrosine phosphorylation occurs during F3-mediated aggregation. Moreover, under aggregation conditions F3 immunoprecipitated from 32P-metabolically labeled 1A cells associated with three major phosphorylated proteins. Interestingly, genistein inhibited the F3-mediated aggregation. Increased tyrosine phosphorylation was also observed using antibody-mediated F3-cross-linking. Furthermore, F3 expressed both in 1A cells and in post-natal mouse cerebellum forms non-covalent soluble complexes with protein tyrosine kinase(s). In cerebellum the F3-associated kinase was identified as fyn. By contrast, a truncated F3 protein, expressed in CHO cells, from which all the FN type III repeats have been deleted, does not associate with a kinase. Cross-linking of the F3-truncated form does not induce modulation of tyrosine phosphorylation. Taken together these data demonstrate that F3 is a molecule that transduces signals through both association with protein tyrosine kinase and modulation of protein tyrosine phosphorylation. The presence of FN type III domains is essential for the activation of the intracellular signaling pathway.

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