Protein tyrosine kinase activation provides an early and obligatory signal in anti-FRP-1/CD98/4F2 monoclonal antibody induced cell fusion mediated by HIV gp160.
The mechanism by which anti-fusion regulatory protein-1 (FRP-1) monoclonal antibody (mAb) induced cell fusion was investigated using U2ME-7 cells that are CD4+U937 cells transfected with the HIV gp160 gene. Protein kinase inhibitors (H-7, H-89, herbimycin A and genistein) suppressed cell fusion of Cd+U2ME-7 cells induced by anti-FRP-1 mAb. H-7 and H-89 also inhibited the cell aggregation, but herbimycin A and genistein did not. Intriguingly, only when herbimycin A was added either before or simultaneously with addition of anti-FRP-1 mAb, was cell fusion suppressed, suggesting that tyrosine kinase is related with the initial step of polykaryocyte formation. Anti-FRP-1 mAb induced the rapid tyrosine phosphorylation of multiple cellular proteins. These effects occurred within 1 min and returned to near baseline by 60 min. The rapid tyrosine phosphorylation was suppressed by herbimycin A and genistein. Although it remains to be determined which protein tyrosine kinase(s) is involved in this response, pp130 tyrosine phosphorylation appears to be a specific and early signal transmitted after the interaction of FRP-1 with a specific antibody. pp130 was present in the cytosol fraction and was distinct from pp125FAK, p130CAS, vinculin, and beta 1-integrin. Thus, our study may present evidence for a novel pathway of protein tyrosine kinases that phosphorylate specific, still unknown protein substrates during polykaryocyte formation.
Tabata
N
N
Department of Microbiology, Mie University School of Medicine, Japan.
Ido
M
M
Suga
S
S
Ohgimoto
S
S
Tsurudome
M
M
Kawano
M
M
Nishio
M
M
Watanabe
N
N
Okamoto
K
K
Komada
H
H
Sakurai
M
M
Ito
Y
Y
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000276:immunology / Q000502:physiology*; D016227:Benzoquinones; D002352:Carrier Proteins / Q000276:immunology / Q000502:physiology*; D002459:Cell Fusion / Q000187:drug effects; D002460:Cell Line; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D027261:Fusion Regulatory Protein-1; D005814:Genes, Viral; D019833:Genistein / Q000494:pharmacology; D019302:HIV Envelope Protein gp160 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D047029:Lactams, Macrocyclic; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011809:Quinones / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D016227:Benzoquinones; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D027261:Fusion Regulatory Protein-1; D019302:HIV Envelope Protein gp160; D047029:Lactams, Macrocyclic; D010750:Phosphoproteins; D011809:Quinones; D017828:Rifabutin; D014443:Tyrosine; C020754:herbimycin; D019833:Genistein; D011505:Protein-Tyrosine Kinases