Expression of exogenous p59fyn modulates signaling in an immature B cell line, WEHI-231.
The WEHI-231 B lymphoma line is representative of immature B cells, which undergo growth arrest/apoptosis following cross-linking of surface immunoglobulin M (sIgM). In B cells, sIgM engagement has been shown to induce immediate (within seconds) activation of src family protein tyrosine kinases (PTKs) such as p53lyn/56lyn, p55blk, p56lck and p59fyn which are associated with B cell antigen receptor (BCR) complex. However, p59fyn expression is very low in both normal immature B cells and apoptosis-prone B cell lines, including WEHI-231. Such a finding prompted us to investigate the effects of ectopic expression of p59fyn in growth regulation of WEHI-231 cells. We have obtained WEHI-231 transfectants expressing the exogenous p59fyn by retroviral mediated gene transfer method. The transfectants demonstrated increased [Ca2+]i level in both the non-stimulated condition and sIgM cross-linking. The expression of ectopic p59fyn also increased the sensitivity of the transfectants to growth arrest signal by sIgM cross-linking. The results suggest that p59fyn can modulate signal transduction and growth regulation when expressed in the immature B cell line.
Iwabuchi
N
N
Department of Immunology, University of Toronto, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada.
Wu
Y
Y
Nguyen
H P
HP
Ido
E
E
Kang
J
J
Bolen
J B
JB
Burkhardt
A
A
Hozumi
N
N
D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D005822:Genetic Vectors / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000201:enzymology* / Q000276:immunology; D051379:Mice; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D051076:Proto-Oncogene Proteins c-fyn; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D014162:Transfection / Q000276:immunology; D014407:Tumor Cells, Cultured
D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn; D002118:Calcium