Modulation of enzymatic activity of Src-family kinases in bovine T cells transformed by Theileria parva.
After infection with sporozoites of the protozoon Theileria parva (Tp) bovine T cells are readily transformed to permanent growth in vivo and in vitro. Their transformed state depends on the constant presence of the parasite but membrane signals remain important. Non-receptor tyrosine kinases play a critical role in the transduction of membrane signals in haematopoietic cells. We have investigated Src-family kinases in bovine T cells transformed by Tp. The T cell receptor-associated tyrosine kinase p60fyn had high activity in all cell lines tested. In addition, weak phosphorylation of 2 novel bands was observed associated with Fyn. In contrast to Fyn, enzymatic activity of p56lck, which in T cells has an essential role in signalling, was low. Furthermore, 1 of 3 Tp transformed cell lines was completely devoid of p56lck indicating that the enzyme is not necessary for the Tp dependent growth of the T cells. In addition to p60fyn and p56lck weak enzymatic activity of 1 splice variant of p53/56lyn was observed after infection of T cells with Tp. These data show that growth transformation by Tp influences kinase activity in bovine T cells. However, they also prove that p56lck does not play an essential role in the transformation mechanism.
Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
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C
Fich
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Klauenberg
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B
Fleischer
B M
BM
Bröker
D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology; D002417:Cattle; D002461:Cell Line, Transformed; D006567:Herpesvirus 2, Saimiriine / Q000502:physiology; D006801:Humans; D019169:Jurkat Cells / Q000201:enzymology / Q000821:virology; D009285:Naphthoquinones / Q000494:pharmacology; D010766:Phosphorylation; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000201:enzymology* / Q000469:parasitology*; D016797:Theileria parva / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
D000981:Antiprotozoal Agents; D009285:Naphthoquinones; D012333:RNA, Messenger; C046326:buparvaquone; D014443:Tyrosine; D019061:src-Family Kinases