Abstract
Tumor-promoting phorbol esters have been found to bind and activate phospholipid/Ca2+-dependent or C-kinase, and several of their effects, including proliferative responses in lymphocytes, have been assumed to be related to activity of this enzyme. However, phorbol esters have also recently been found to stimulate tyrosine phosphorylation in certain other cell types, and we therefore studied tyrosine kinase activity in normal and chronic lymphocytic leukemia (CLL) peripheral blood B lymphocytes stimulated with phorbol ester. High levels of tyrosine labeling were observed in unstimulated cells with major endogenous substrates of 75K, 66K, 43K, and 28K in Triton-soluble material, and of 56K to 61K in Triton-insoluble material; this profile was essentially similar in normal and CLL B cells. Treatment with phorbol ester for time periods varying from 20 min to 48 hr led to qualitative increases in tyrosine labeling of these phosphoproteins, as measured both in vitro and in intact cells 'in vivo'. Although the relative abundance of tyrosine phosphorylation as a percentage of total labeling was variable due to concomitant enhancement of serine and threonine phosphorylation, exogenous peptide substrate assays confirmed the increased tyrosine kinase activity quantitatively. Enhanced tyrosine phosphorylation was succeeded or accompanied in both normal and abnormal B cells by cellular activation, as judged by increased [3H]thymidine uptake, and terminal differentiation of CLL cells. These findings provide further evidence implicating tyrosine kinases in B lymphocyte activation.
| Original language | English |
|---|---|
| Pages (from-to) | 3448-3453 |
| Number of pages | 6 |
| Journal | Journal of Immunology |
| Volume | 135 |
| Issue number | 5 |
| State | Published - Dec 1 1985 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Immunology
Cite this
Phorbol ester induces tyrosine phosphorylation in normal and abnormal human B lymphocytes. / Nel, A. E.; Navailles, M.; Rosberger, D. F.; Landreth, G. E.; Goldschmidt-Clermont, Pascal; Baldwin, G. J.; Galbraith, R. M.
In: Journal of Immunology, Vol. 135, No. 5, 01.12.1985, p. 3448-3453.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phorbol ester induces tyrosine phosphorylation in normal and abnormal human B lymphocytes
AU - Nel, A. E.
AU - Navailles, M.
AU - Rosberger, D. F.
AU - Landreth, G. E.
AU - Goldschmidt-Clermont, Pascal
AU - Baldwin, G. J.
AU - Galbraith, R. M.
PY - 1985/12/1
Y1 - 1985/12/1
N2 - Tumor-promoting phorbol esters have been found to bind and activate phospholipid/Ca2+-dependent or C-kinase, and several of their effects, including proliferative responses in lymphocytes, have been assumed to be related to activity of this enzyme. However, phorbol esters have also recently been found to stimulate tyrosine phosphorylation in certain other cell types, and we therefore studied tyrosine kinase activity in normal and chronic lymphocytic leukemia (CLL) peripheral blood B lymphocytes stimulated with phorbol ester. High levels of tyrosine labeling were observed in unstimulated cells with major endogenous substrates of 75K, 66K, 43K, and 28K in Triton-soluble material, and of 56K to 61K in Triton-insoluble material; this profile was essentially similar in normal and CLL B cells. Treatment with phorbol ester for time periods varying from 20 min to 48 hr led to qualitative increases in tyrosine labeling of these phosphoproteins, as measured both in vitro and in intact cells 'in vivo'. Although the relative abundance of tyrosine phosphorylation as a percentage of total labeling was variable due to concomitant enhancement of serine and threonine phosphorylation, exogenous peptide substrate assays confirmed the increased tyrosine kinase activity quantitatively. Enhanced tyrosine phosphorylation was succeeded or accompanied in both normal and abnormal B cells by cellular activation, as judged by increased [3H]thymidine uptake, and terminal differentiation of CLL cells. These findings provide further evidence implicating tyrosine kinases in B lymphocyte activation.
AB - Tumor-promoting phorbol esters have been found to bind and activate phospholipid/Ca2+-dependent or C-kinase, and several of their effects, including proliferative responses in lymphocytes, have been assumed to be related to activity of this enzyme. However, phorbol esters have also recently been found to stimulate tyrosine phosphorylation in certain other cell types, and we therefore studied tyrosine kinase activity in normal and chronic lymphocytic leukemia (CLL) peripheral blood B lymphocytes stimulated with phorbol ester. High levels of tyrosine labeling were observed in unstimulated cells with major endogenous substrates of 75K, 66K, 43K, and 28K in Triton-soluble material, and of 56K to 61K in Triton-insoluble material; this profile was essentially similar in normal and CLL B cells. Treatment with phorbol ester for time periods varying from 20 min to 48 hr led to qualitative increases in tyrosine labeling of these phosphoproteins, as measured both in vitro and in intact cells 'in vivo'. Although the relative abundance of tyrosine phosphorylation as a percentage of total labeling was variable due to concomitant enhancement of serine and threonine phosphorylation, exogenous peptide substrate assays confirmed the increased tyrosine kinase activity quantitatively. Enhanced tyrosine phosphorylation was succeeded or accompanied in both normal and abnormal B cells by cellular activation, as judged by increased [3H]thymidine uptake, and terminal differentiation of CLL cells. These findings provide further evidence implicating tyrosine kinases in B lymphocyte activation.
UR - http://www.scopus.com/inward/record.url?scp=0022181098&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0022181098&partnerID=8YFLogxK
M3 - Article
C2 - 3876385
AN - SCOPUS:0022181098
VL - 135
SP - 3448
EP - 3453
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 5
ER -