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Cellular depletion of p56 lck during thymocyte apoptosis
Author(s) -
GarciaWelsh Adrienne,
Laskin Debra L.,
Shuler Randy L.,
Laskin Jeffrey D.
Publication year - 1994
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.56.4.528
Subject(s) - biology , apoptosis , thymocyte , programmed cell death , dna fragmentation , microbiology and biotechnology , cell culture , cd3 , kinase , tyrosine kinase , t cell , signal transduction , cd8 , antigen , biochemistry , immune system , immunology , genetics
The src‐related protein tyrosine kinase p56 lck is thought to be important in regulating maturation and functional responsiveness of T cells and thymocytes. In the present studies we report that expression of p56 lck is suppressed during apoptosis. Using primary cultures of rat thymocytes, we found that agents that are effective in inducing apoptosis, including okadaic acid, dexamethasone, and antibodies to the CD3 receptor, also deplete cells of p56 lck . This process is rapid, occurring within 24 h, and is not due to cytotoxicity. Inhibition of DNA fragmentation in apoptotic cells with the endonuclease inhibitor ZnCl 2 failed to prevent depletion of p56 lck , suggesting that it was not a consequence of the DNA degradation process. Using the thymic lymphoma cell line LSTRA, apoptosis was also associated with cellular depletion of p56. In contrast to thymocytes, this process required 48–72 h possibly because these cells overexpress p56 lck . Although at this time we are uncertain as to the precise role of p56 lck in the process of apoptosis, our results indicate that changes in the expression of this protein in thymocytes is an important marker of programmed cell death. J. Leukoc. Biol. 56: 528–532; 1994.