scholarly journals Cosignaling of NCAM via lipid rafts and the FGF receptor is required for neuritogenesis

2002 ◽  
Vol 157 (3) ◽  
pp. 521-532 ◽  
Author(s):  
Philipp Niethammer ◽  
Markus Delling ◽  
Vladimir Sytnyk ◽  
Alexander Dityatev ◽  
Kiyoko Fukami ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Lipid Raft ◽  
Tyrosine Kinases ◽  
Hippocampal Neurons ◽  
Fgf Receptor ◽  
Nonreceptor Tyrosine Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Neural Cell Adhesion ◽  
Nonreceptor Tyrosine Kinases

The neural cell adhesion molecule (NCAM) has been reported to stimulate neuritogenesis either via nonreceptor tyrosine kinases or fibroblast growth factor (FGF) receptor. Here we show that lipid raft association of NCAM is crucial for activation of the nonreceptor tyrosine kinase pathway and induction of neurite outgrowth. Transfection of hippocampal neurons of NCAM-deficient mice revealed that of the three major NCAM isoforms only NCAM140 can act as a homophilic receptor that induces neurite outgrowth. Disruption of NCAM140 raft association either by mutation of NCAM140 palmitoylation sites or by lipid raft destruction attenuates activation of the tyrosine focal adhesion kinase and extracellular signal–regulated kinase 1/2, completely blocking neurite outgrowth. Likewise, NCAM-triggered neurite outgrowth is also completely blocked by a specific FGF receptor inhibitor, indicating that cosignaling via raft-associated kinases and FGF receptor is essential for neuritogenesis.

scholarly journals Different Protein Tyrosine Kinases Are Required for B Cell Antigen Receptor–mediated Activation of Extracellular Signal–Regulated kinase, c-Jun NH2-terminal Kinase 1, and p38 Mitogen-activated Protein Kinase

1998 ◽  
Vol 188 (7) ◽  
pp. 1297-1306 ◽  
Author(s):  
Aimin Jiang ◽  
Andrew Craxton ◽  
Tomohiro Kurosaki ◽  
Edward A. Clark
Keyword(s):  
B Cell ◽  
P38 Mapk ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinases ◽  
B Cell Antigen Receptor ◽  
Mapk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Erk2 Activation

B cell antigen receptor (BCR) cross-linking activates three distinct families of nonreceptor protein tyrosine kinases (PTKs): src-family kinases, Syk, and Btk; these PTKs are responsible for initiating downstream events. BCR cross-linking in the chicken DT40 B cell line also activates three distinct mitogen-activated protein kinases (MAPKs): extracellular signal–regulated kinase (ERK)2, c-jun NH2-terminal kinase (JNK)1, and p38 MAPK. To dissect the functional roles of these PTKs in MAPK signaling, activation of MAPKs was examined in various PTK-deficient DT40 cells. BCR-mediated activation of ERK2, although maintained in Lyn-deficient cells, was abolished in Syk-deficient cells and partially inhibited in Btk-deficient cells, indicating that BCR-mediated ERK2 activation requires Syk and that sustained ERK2 activation requires Btk. BCR-mediated JNK1 activation was maintained in Lyn-deficient cells but abolished in both Syk- and Btk-deficient cells, suggesting that JNK1 is activated via a Syk- and Btk-dependent pathway. Consistent with this, BCR-mediated JNK1 activation was dependent on intracellular calcium and phorbol myristate acetate–sensitive protein kinase Cs. In contrast, BCR-mediated p38 MAPK activation was detected in all three PTK-deficient cells, suggesting that no single PTK is essential. However, BCR-mediated p38 MAPK activation was abolished in Lyn/Syk double deficient cells, demonstrating that either Lyn or Syk alone may be sufficient to activate p38 MAPK. Our data show that BCR-mediated MAPK activation is regulated at the level of the PTKs.

scholarly journals Two Distinct Phosphorylation Pathways Have Additive Effects on Abl Family Kinase Activation

2003 ◽  
Vol 23 (11) ◽  
pp. 3884-3896 ◽  
Author(s):  
Keith Q. Tanis ◽  
Darren Veach ◽  
Henry S. Duewel ◽  
William G. Bornmann ◽  
Anthony J. Koleske
Keyword(s):  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Intramolecular Interactions ◽  
Activation Loop ◽  
Additive Effects ◽  
Nonreceptor Tyrosine Kinase ◽  
Kinase Activation ◽  
Surface Receptors ◽  
Nonreceptor Tyrosine Kinases ◽  
Stimulation Of

ABSTRACT The activities of the related Abl and Arg nonreceptor tyrosine kinases are kept under tight control in cells, but exposure to several different stimuli results in a two- to fivefold stimulation of kinase activity. Following the breakdown of inhibitory intramolecular interactions, Abl activation requires phosphorylation on several tyrosine residues, including a tyrosine in its activation loop. These activating phosphorylations have been proposed to occur either through autophosphorylation by Abl in trans or through phosphorylation of Abl by the Src nonreceptor tyrosine kinase. We show here that these two pathways mediate phosphorylation at distinct sites in Abl and Arg and have additive effects on Abl and Arg kinase activation. Abl and Arg autophosphorylate at several sites outside the activation loop, leading to 5.2- and 6.2-fold increases in kinase activity, respectively. We also find that the Src family kinase Hck phosphorylates the Abl and Arg activation loops, leading to an additional twofold stimulation of kinase activity. The autoactivation pathway may allow Abl family kinases to integrate or amplify cues relayed by Src family kinases from cell surface receptors.

Cardioprotection involves activation of NF-κB via PKC-dependent tyrosine and serine phosphorylation of IκB-α

2003 ◽  
Vol 285 (4) ◽  
pp. H1753-H1758 ◽  
Author(s):  
Jun Zhang ◽  
Peipei Ping ◽  
Thomas M. Vondriska ◽  
Xian-Liang Tang ◽  
Guang-Wu Wang ◽  
...  
Keyword(s):  
Ischemic Preconditioning ◽  
Tyrosine Kinases ◽  
Molecular Mechanisms ◽  
Coronary Occlusion ◽  
Kinase Inhibitor ◽  
Serine Phosphorylation ◽  
Inhibitory Protein ◽  
Nonreceptor Tyrosine Kinase ◽  
Pkc Inhibitor ◽  
Nonreceptor Tyrosine Kinases

Previous studies indicated that activation of PKC and Src tyrosine kinases by ischemic preconditioning (PC) may participate in the activation of NF-κB. However, the molecular mechanisms underlying activation of NF-κB during ischemic PC remain unknown. In the hearts of conscious rabbits, it was found that ischemic PC (6 cycles of 4-min coronary occlusion and 4-min reperfusion) significantly induced both tyrosine (+226.9 ± 42%) and serine (+137.0 ± 36%) phosphorylation of the NF-κB inhibitory protein IκB-α, concomitant with increased activation of the IκB-α kinases IKKα (+255.0 ± 46%) and IKKβ (+173.1 ± 35%). Furthermore, both tyrosine and serine phosphorylation of IκB-α were blocked by pretreatment with either the nonreceptor tyrosine kinase inhibitor lavendustin-A (LD-A) or the PKC inhibitor chelerythrine (Che) (both given at doses previously shown to block ischemic PC). Interestingly, Che completely abolished PC-induced activation of IKKα/β, whereas LD-A had no effect. In addition, IκB-α protein level did not change during ischemic PC. Together, these data indicate that ischemic PC-induced activation of NF-κB occurs through both tyrosine and serine phosphorylation of IκB-α and is regulated by nonreceptor tyrosine kinases and PKC.

scholarly journals Inhibition of RET tyrosine kinase by SU5416

2006 ◽  
Vol 37 (2) ◽  
pp. 199-212 ◽  
Author(s):  
Luca Mologni ◽  
Elisa Sala ◽  
Sara Cazzaniga ◽  
Roberta Rostagno ◽  
Thomas Kuoni ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Vascular Endothelial Cell ◽  
Growth Factor Receptor ◽  
Selective Inhibition ◽  
Negative Control ◽  
Vascular Endothelial ◽  
Extracellular Signal Regulated Kinase ◽  
Naturally Occurring ◽  
Extracellular Signal ◽  
Thyroid Neoplasia

Thyroid neoplasia is frequently associated with rearranged during transfection (RET) proto-oncogene mutations that cause hyperactivation of RET kinase activity. Selective inhibition of RET-mediated signaling should lead to an efficacious therapy. SU5416 is a potent inhibitor of vascular endothelial cell growth factor receptor, c-Kit, and FLT-3 receptor tyrosine kinases presently used in clinical trials. We found that SU5416 inhibits RET with similar potency, both in cell-free assays and in cells, thus causing proliferation arrest in oncogenic RET-transfected cells and in papillary thyroid carcinoma (PTC) cells expressing the RET/PTC1 oncogene, but not in RET-negative control cells. SU5416 inhibited RET-mediated signaling through the extracellular signal regulated kinase (ERK) and JNK pathways. In addition, we show that a naturally occurring MEN2 mutation at codon 804 confers resistance to SU5416, but not to the related compound SU4984. We provide a possible explanation to these results by using molecular docking. Finally, SU5416 was also assessed against an array of 52 tyrosine and serine/threonine kinases.

Sign in / Sign up

Export Citation Format

Share Document