Stimulation of protein tyrosine phosphorylation by the B-lymphocyte antigen receptor

Nature ◽  
1990 ◽  
Vol 345 (6278) ◽  
pp. 810-813 ◽  
Author(s):  
Michael R. Gold ◽  
Debbie A. Law ◽  
Anthony L. DeFranco

1992 ◽  
Vol 92 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Masanobu Koide ◽  
Yasuhiro Kawahara ◽  
Terutaka Tsuda ◽  
Yoshihiro Ishida ◽  
Kozui Shii ◽  
...  


1995 ◽  
Vol 181 (3) ◽  
pp. 1005-1014 ◽  
Author(s):  
K M Kim ◽  
M Reth

Most mature B lymphocytes coexpress two classes of antigen receptor, immunoglobulin (Ig)M and IgD. The differences in the signal transduction from the two receptors are still a matter of controversy. We have analyzed B cell lines expressing IgM or IgD antigen receptors with the same antigen specificity. Cross-linking of these receptors with either antigen, or class-specific antibodies, results in the activation of protein tyrosine kinases and the phosphorylation of the same substrate proteins. The kinetic and the intensity of phosphorylation, however, was quite different between the two receptors when they were cross-linked by antigen. In membrane IgM-expressing cells, the substrate phosphorylation reached a maximum after 1 minute and diminished after 60 minutes whereas, in the membrane IgD-expressing cells, the substrate phosphorylation increased further over time, reached its maximum at 60 minutes, and persisted longer than 240 minutes after exposure to antigen. As a result, the intensity of protein tyrosine phosphorylation induced by cross-linking of membrane IgD was stronger than that induced by membrane IgM. Studies of chimeric receptors demonstrate that only the membrane-proximal C domain and/or the transmembrane part of membrane-bound IgD molecule is required for the long-lasting substrate phosphorylation. Together, these data suggest that the signal emission from the two receptors is controlled differently.



1995 ◽  
Vol 108 (1-2) ◽  
pp. 35-42 ◽  
Author(s):  
Michaela Luconi ◽  
Lorella Bonaccorsi ◽  
Csilla Krausz ◽  
Ginetta Gervasi ◽  
Gianni Forti ◽  
...  


1996 ◽  
Vol 271 (4) ◽  
pp. C1085-C1097 ◽  
Author(s):  
T. Ohtsuki ◽  
M. Matsumoto ◽  
K. Kitagawa ◽  
T. Mabuchi ◽  
K. Mandai ◽  
...  

Glutamate triggers neuronal degeneration after ischemia-reperfusion in the brain. However, the details of intracellular signal transduction that propagates cell death remain unknown. The present work investigated whether protein tyrosine phosphorylation mediates neuronal death in the ischemic brain. Transient forebrain ischemia for 5-10 min in Mongolian gerbils or intoxication with the glutamate analogue kainic acid (12 mg/kg) in Sprague-Dawley rats caused neuronal death selectively in the hippocampus 2-4 days or 1 day later, respectively. Under these conditions, 160-, 115-, 105-, 92-, and 85-kDa proteins showed a significant increase in tyrosyl residue phosphorylation selectively in the hippocampus 3-12 h after ischemia or 4-8 h after kainic acid-induced seizures. Tyrosine kinases, including pp60c-src, were activated without a change of tyrosine phosphatases. Administration of radicicol, a selective inhibitor of tyrosine kinases, attenuated stimulation of tyrosine phosphorylation and hippocampal degeneration after ischemia or kainic acid injection. The results suggest that protein tyrosine phosphorylation might propagate delayed neuronal death in the mature hippocampus through glutamate overload after ischemia-reperfusion.





1990 ◽  
Vol 269 (2) ◽  
pp. 431-436 ◽  
Author(s):  
C K Huang ◽  
V Bonak ◽  
G R Laramee ◽  
J E Casnellie

Protein tyrosine phosphorylation in rabbit peritoneal neutrophils was examined by immunoblotting with antibodies specific for phosphotyrosine. Stimulation of the neutrophils with chemotactic factor fMet-Leu-Phe (10 nM) caused rapid increases of tyrosine phosphorylation of several proteins with apparent molecular masses of (Group A) 54-58 kDa and 100-125 kDa and (Group B) 36-41 kDa. Stimulation of Group A proteins was observed by fMet-Leu-Phe (10 nM, maximum at 20 s) and A23187 (1 microM, 1 min). Stimulation of Group B proteins was observed by fMet-Leu-Phe (ED50 0.15 nM, 1 min), leukotriene B4 (ED50 0.15 nM, 1 min), phorbol 12-myristate 13-acetate (PMA) (ED50 25 ng/ml, 10 min) and partially by ionophore A23187 (1 microM, 1 min). Pretreatment of the cell with the protein kinase inhibitor H-7 (25 microM, 5 min) and PMA (0.1 microgram/ml, 3 min) partially inhibited the fMet-Leu-Phe effect. However, pretreatment of the cells with quin 2/AM (20 microM, 10 min) completely inhibited the fMet-Leu-Phe effect. The results indicate that rapid regulation of tyrosine phosphorylation is an early event occurring in stimulated neutrophils. Furthermore the effect of fMet-Leu-Phe on tyrosine phosphorylation may require Ca2+ mobilization and may partially require the activity of H-7-sensitive protein kinases.



1994 ◽  
Vol 72 (11) ◽  
pp. 1434-1439 ◽  
Author(s):  
Joseph Di Salvo ◽  
Gabrielle Pfitzer ◽  
Lori A. Semenchuk

Our studies are guided by the novel hypothesis that protein tyrosine phosphorylation is an important mechanism for regulating contraction of smooth muscle. Several lines of evidence are reviewed which suggest that enhanced tyrosine phosphorylation participates in mechanisms that regulate cytosolic Ca2+ and Ca2+ sensitivity for contraction. First, vanadate-induced contraction of guinea-pig taenia coli is functionally linked to enhanced protein tyrosine phosphorylation of at least three substrates, apparently resulting from vanadate-mediated inhibition of protein tyrosine phosphatase activity. Second, vanadate-induced contraction is dependent on extracellular Ca2+. Third, increases in cytosolic Ca2+ resulting from stimulation of αi-adrenergic receptors in cultured canine vascular smooth muscle cells are associated with enhanced tyrosine phosphorylation and are inhibited by genistein, a potent inhibitor of tyrosine kinase activity. Fourth, genistein markedly and reversibly suppresses Ca2+ sensitivity for contraction in ileal longitudinal smooth muscle permeabilized with staphylococcal α-toxin. Moreover, the same or similar substrates (e.g., 42–45, 70, 80–85, 95, 100, 110, 116, and 205 kDa) are tyrosine phosphorylated in response to Ca2+ or stimulation of muscarinic or αi-adrenergic receptors. Collectively, these data strongly suggest that tyrosine phosphorylation is an important mechanism for regulation of smooth muscle contraction.Key words: actin–myosin interaction, calcium sensitivity, genistein, permeabilized smooth muscle, tyrosine kinase activity, tyrosine phosphatase activity, vascular smooth muscle cells, vanadate.



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