Tyrosine phosphorylation and activation of focal adhesion kinase (p125FAK) by BCR-ABL oncoprotein.
Focal adhesion kinase (p125FAK; FAK) is a protein tyrosine kinase that is tyrosine-phosphorylated in response to v-src-mediated transformation, cell adhesion, and stimulation with neuropeptides. To elucidate a possible functional relationship between FAK and BCR-ABL oncoprotein detected in Philadelphia chromosome-positive (Ph+) leukemias, we investigated the tyrosine phosphorylation state of FAK in a murine growth factor-dependent cell line and in its stable human bcr-abl cDNA transfectant. In interleukin-3 (IL-3)-dependent NFS/N1.H7 cells, tyrosine phosphorylation of FAK was not detected after stimulation with either IL-3 or Steel factor (SLF), both of which involve Ras-mediated signaling pathways. However, stable gene transfection with p210bcr-abl cDNA into H7 cells made these cells growth factor-independent for proliferation and resulted in constitutive tyrosine phosphorylation and kinase activation of FAK. Constitutive phosphorylation and activation of FAK was also observed in all Ph+ leukemia cell lines examined--that is, K562, TS9;22, and YS9;22, which express p210BCR-ABL, and NALM-21 and OM9;22, which express p185BCR-ABL. Ph-negative (Ph-) cell lines, such as MO7e and JM, did not show any detectable tyrosine phosphorylation of FAK. FAK phosphorylation in BCR-ABL-expressing cells was inhibited in a dose-dependent manner by cytochalasin D, a reagent that disrupts the intracellular network of actin filaments. However, no suppression of kinase activity or protein expression of BCR-ABL was observed after treatment with cytochalasin D. A physical association between BCR-ABL and FAK was not apparent. These data suggest that BCR-ABL may be involved in the activation of FAK. Moreover, FAK may be distinct from components in Ras-mediated signaling cascades that are activated by stimulation of myeloid cells with various cytokines.
Gotoh
A
A
First Department of Internal Medicine, Tokyo Medical College, Japan.
Miyazawa
K
K
Ohyashiki
K
K
Tauchi
T
T
Boswell
H S
HS
Broxmeyer
H E
HE
Toyama
K
K
D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D015638:Cytochalasin D / Q000494:pharmacology; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism*; D051379:Mice; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D016315:Proto-Oncogene Proteins c-abl / Q000096:biosynthesis / Q000302:isolation & purification; D011519:Proto-Oncogenes; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D019089:Stem Cell Factor / Q000494:pharmacology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D015815:Cell Adhesion Molecules; D007377:Interleukin-3; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D019000:Phosphotyrosine; D015638:Cytochalasin D; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; C496050:PTK2 protein, human; D016315:Proto-Oncogene Proteins c-abl; C496051:Ptk2 protein, mouse