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Syk Mutation in Jurkat E6-derived Clones Results in Lack of p72 Expression
The human leukemic Jurkat cell line is commonly used as a model cellular system to study T lymphocyte signal transduction. Various clonal derivatives of Jurkat T cells exist which display different characteristics with regard to responses to external stimuli. Among these, the E6-1 clone of Jurkat T...
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Published in: | The Journal of biological chemistry 1995-11, Vol.270 (44), p.26533 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Online Access: | Get full text |
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Summary: | The human leukemic Jurkat cell line is commonly used as a model cellular system to study T lymphocyte signal transduction.
Various clonal derivatives of Jurkat T cells exist which display different characteristics with regard to responses to external
stimuli. Among these, the E6-1 clone of Jurkat T cells has been used as a parental line from which numerous important somatic
mutant clones have been generated. During the course of experiments examining signals initiated by the T cell antigen receptor
in an E6-1-derived Jurkat cell clone J.CaM1, we observed that the 72-kilodalton Syk protein tyrosine kinase previously found
in other Jurkat cells was not detected. Upon further analysis it was determined that Syk transcripts from the J.CaM1 cells
as well as the parental E6-1 cells contain a single guanine nucleotide insertion at position 92. This nucleotide insertion
results in a shift in the Syk open reading frame leading to alternate codon usage as well as the generation of a termination
codon at position 109. Thus, Syk transcripts in E6-1 cells and E6-1-derived clones are predicted to be capable of encoding
only the first 33 amino acids of the 630-amino acid wild type Syk. These findings are incompatible with a recently proposed
model of T cell antigen receptor signal transduction based, in part, on experiments conducted using E6-1-derived cells, suggesting
that Syk might play a role upstream of Lck and Zap70. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.270.44.26533 |